MORPHOLOGICAL AND NUTRITIONAL DEVELOPMENT OF THREE SPECIES OF
NURSERY-GROWN HARDWOOD SEEDLINGS IN TENNESSEE
Except where reference is made to the work of others, the work described in this thesis is
my own or was done in collaboration with my advisory committee. This thesis does not
include proprietary or classified information
_______________________________________________________
Humberto Zeraib dos Santos
Certificate of Approval:
_________________________________ _________________________________
B. Graeme Lockaby Kenneth L. McNabb, Chair
Professor Associate Professor
School of Forestry and Wildlife Sciences School of Forestry and Wildlife Sciences
_________________________________ _________________________________
David South Stephen L. McFarland,
Professor Acting Dean
School of Forestry and Wildlife Sciences Graduate School
MORPHOLOGICAL AND NUTRITIONAL DEVELOPMENT OF THREE SPECIES OF
NURSERY-GROWN HARDWOOD SEEDLINGS IN TENNESSEE
Humberto Zeraib dos Santos
A Thesis
Submitted to
the Graduate Faculty of
Auburn University
in Partial Fulfillment of the
Requirements for the
Degree of
Master of Science
Auburn, Alabama
December 15, 2006
iii
MORPHOLOGICAL AND NUTRITIONAL DEVELOPMENT OF THREE SPECIES OF
NURSERY-GROWN HARDWOOD SEEDLINGS IN TENNESSEE
Humberto Zeraib dos Santos
Permission is granted to Auburn University to make copies of this thesis at its discretion,
upon the request of individuals or institutions and at their expenses. The author reserves
all publications rights.
___________________
Signature of Author
___________________
Date of Graduation
iv
VITA
Humberto Zeraib dos Santos, son of Norival dos Santos and Ivone Calixto Zeraib
dos Santos, was born April 11, 1974 in Sao Paulo, Sao Paulo-Brazil. He attended the
Escola Superior de Agricultura ?Luiz de Queiroz? at the University of Sao Paulo and
graduated with a Bachelor of Science degree in Forestry in December, 2003. He served as
Visiting Scientist in the Southern Forest Nursery Management Cooperative at Auburn
University for one year. After working as a Visiting Scientist he entered Graduate
School at Auburn University in January 2004 and accepted a research assistantship under
Kenneth L. McNabb.
v
Style manual for Journal used Auburn University Guide to Preparation and
Submission of Theses and Dissertations 2005 .
Computer software used Microsoft Word 2003
?
, Microsoft Excel 2003
?
, SAS
version 9.1, and SPSS version 11.5 .
vi
THESIS ABSTRACT
MORPHOLOGICAL AND NUTRITIONAL DEVELOPMENT OF THREE SPECIES OF
NURSERY-GROWN HARDWOOD SEEDLINGS IN TENNESSEE
Humberto Zeraib dos Santos
Master of Science, December 15, 2006
(B. S. University of S?o Paulo, 2003)
113 Typed Pages
Directed by Ken McNabb
We followed the morphological and nutritional development of three common
hardwood species growing under typical cultural practices in a southern hardwood
nursery. Yellow poplar was by far the largest seedling at the end of the season, followed
by Nuttall oak and green ash. Seasonal periodicity of morphological development varied
by species, although large increases in lateral root weight occurred in late fall for all three
species. Coefficients of variation for the morphological components over time were high
for all three species and most parameters. All three species had strong correlations
between root collar diameter (RCD) and many other morphological parameters including
number of first order lateral roots.
vii
The seasonal periodicity of nutrient concentrations, translocation and allocation
were documented. No changes in soil carbon and organic matter content were found,
probably as a result of the addition of mulch and leaf litterfall. In spite of similar
fertilization regimes, foliar nutrient concentrations varied by species. Yellow poplar
appeared to be the most efficient at withdrawing nutrients from senescent leaves while
Nuttall oak had higher nutrient translocation efficiencies. Large amounts of fertilizer
elements were removed by harvesting, but overall nitrogen and phosphorous balance
(applied fertilizer minus removed) was positive. Nitrogen use efficiency was relatively
high for all species. Yellow poplar had the highest nitrogen removal efficiency and
biomass productivity, indicating higher use of fertilizer materials.
viii
ACKNOWLEDGMENTS
The author would like to thank his committee members, Dr. Ken McNabb, Dr.
David South, and Dr. Graeme Lockaby for their assistance and direction throughout this
study. Dr. Ken McNabb also deserves special thanks for his priceless assistance, patience
and guidance throughout the research process. Thanks to Tommy Hill for his assistance
in both laboratory and field. The author gratefully acknowledges the Southern Forest
Nursery Management Cooperative for the financial support and personnel assistance and
the East Tennessee Nursery, especially Mr. John Conn and Mr. Tom Strickland for their
constant help and support during field collection. I would like to thank to Dr. Bill Carey
and Dr. Scott Enebak for their support and Patricia Lima for her assistance in the
laboratory. The author also recognizes his family support; particularly his father Norival,
mother Ivone, and sister Simone whose unconditional love and support has always been a
source of strength. Finally, the author also would like to thank Veruska Chiaranda for her
love and endurance during the three years we have been apart.
ix
TABLE OF CONTENTS
LIST OF TABLES??????????????????????.??... xi
LIST OF FIGURES????????????????????????.. xiii
CHAPTER I.
Morphological and Nutritional Development of Three Species
of Nursery-Grown Hardwood Seedlings in Tennessee???......... 1
Introduction????????????????????....... 1
Hardwood Seedling Culture???????????????.. 3
Hardwood Seedling Nutrition?????????????........ 5
Hardwood Seedling Quality???????????????.. 6
References??????????????????????.. 9
CHAPTER II
Morphological Development of Three Species of
Nursery-Grown Hardwood Seedlings in Tennessee??????.. 15
Abstract???????????????????????. 15
Introduction?????????????????????? 16
Materials and Methods?????????????????.. 18
Nursery location and culture??????????? 18
Cultural practices???????????????. 18
Sampling design??????????????....... 19
Measurements???????????????...... 20
Analysis??????????????????? 21
Results???????????????????????? 22
Nuttall oak????????????????....... 22
Yellow poplar???????????????....... 28
Green ash??????????????????. 33
Discussion??????????????????????.. 38
Seedling size?????????????????. 38
Growth periodicity??????????????... 39
Intra-specific variability????????????... 40
x
Correlations of Morphological parameters?????... 42
Implications for seedling production???????? 42
Conclusions?????????????????????? 44
References??????????????????????.. 45
CHAPTER III
Nutritional Development of Three Species of Nursery-Grown
Hardwood Seedlings in Tennessee????????????? 48
Abstract???????????????????????.. 48
Introduction?????????????????????? 49
Materials and Methods?????????????????.. 52
Nursery location and culture??????????? 52
Cultural practices???????????????. 53
Sampling design???????????????... 55
Soil analysis???..?????????????? 56
Measurements????????????????.. 56
Analysis??????????????????... 57
Results???????????????????????? 60
Soil chemical analysis???...?????????... 60
NPK concentrations and contents in the seedling tissues. 68
Translocation efficiencies????????????. 76
Seedling nutrient exports??.?????????? 77
Nutrient use efficiencies...???????????... 79
Discussion??????????????????????... 81
Soil Chemistry??????????.?????? 81
Seedling nutrition??????????.????? 82
Nutrient use efficiencies...???????????... 85
Implication for nursery management???????... 86
Conclusions?????????????????????? 87
References??????????????????????.. 89
APPENDIX???????????????????????????... 95
xi
LIST OF TABLES
II.
1. Elemental fertilizer application for the three hardwood species grown at
the Tennessee Division of Forestry Nursery, East Tennessee
Nursery??????.....................................................................................20
2. Average value for morphological parameters of Nuttall oak seedlings
sampled on specific dates at the Tennessee Division of Forestry Nursery......25
3. R
2
values for regressions between bareroot Nuttall oak seedling
morphological variables sampled from July to November at the East
Tennessee Nursery at Delano, TN?..???????????????.26
4. Average value for morphological parameters of yellow poplar seedlings
sampled on specific dates at the Tennessee Division of Forestry Nursery ?.30
5. R
2
values for regressions between bareroot yellow poplar seedling
morphological variables sampled from July to November at the East
Tennessee Nursery at Delano, TN...????????????????31
6. Average value for morphological parameters of green ash seedlings
sampled on specific dates at the Tennessee Division of Forestry Nursery......35
7. R
2
values for regressions between bareroot green ash seedling
morphological variables sampled from July to November at the East
Tennessee Nursery at Delano, TN?...............................................................36
8. Growth of RCD, height, and root mass for yellow poplar, Nuttall oak, and
green ash during three periods of the nursery growing season expressed as
a percentage of the November sample value???????????.?..40
III.
9. Elemental fertilizer application for the three hardwood species grown at
Tennessee Division of Forestry, East Tennessee Nursery???????...54
10. Nutrient levels applied through a mulch application to green ash and yellow
poplar nursery beds ??????????????????.????55
xii
11. Soil chemical analysis for Nuttall oak at the Tennessee Division of
Forestry nursery during the 2004 crop season????????..???...61
12. Soil chemical analysis for yellow poplar at the Tennessee Division of
Forestry nursery during the 2004 crop season?.????????.??...62
13. Soil chemical analysis for green ash at the Tennessee Division of Forestry
nursery during the 2004 crop season ?.???????????..??...63
14. Macro and micronutrient concentrations and deposition through hardwood
seedling litterfall for the 2004 crop season?????????????..65
15. Average foliar nutrient concentrations of three hardwood species sampled
periodically from May through November at the Tennessee Division of
Forestry Nursery?????...?????????????????...67
16. Seedling resorption efficiency (RE) for the three hardwood species
produced in the Tennessee Division of Forestry Nursery??.??......??.76
17. Seedling translocation efficiency (TE) for the three hardwood species
produced in the Tennessee Division of Forestry Nursery??????........77
18. Macro and micronutrients removed through harvesting three hardwood
seedling species grown at the Tennessee Division of Forestry Nursery.??.78
19. Nitrogen and phosphorous balance for fertilizer application and removal
through the harvest of three hardwood species grown at the Tennessee
Division of Forestry Nursery ?...????????????????...79
20. Nitrogen and phosphorus fertilization and seedling biomass for the three
hardwood species produced at the Tennessee Division of Forestry Nursery.79
21. Seedling nitrogen partial factor of productivity (PFP), nitrogen use
efficiency (NUE), and crop nitrogen removal efficiency (NRE) for the
three hardwood nursery cultures samples in November??.???.....??80
22. Nutrient use efficiencies of some forest trees and conventional agricultural
crops (Calculated for the aboveground material at harvesting)?????...86
xiii
LIST OF FIGURES
II.
1. Nitrogen, phosphorous, and potassium in the leaves of three hardwood
species grown at the Tennessee Division of Forestry Nursery (NO=Nuttall
oak, YP=yellow poplar, GA=green ash) (Bars reported with
standard error).???????????????????..??.....?..70
2. Nitrogen, phosphorous, and potassium in the stems and branches of three
hardwood species grown at the Tennessee Division of Forestry Nursery
(NO=Nuttall oak, YP=yellow poplar, GA=green ash) (Bars reported with
standard error).??????????????????????...?..71
3. Nitrogen, phosphorous, and potassium in taproot component of three
hardwood species grown at the Tennessee Division of Forestry Nursery
(NO=Nuttall oak, YP=yellow poplar, GA=green ash) (Bars reported with
standard error).??????????????????????...?..72
4. Nitrogen, phosphorous, and potassium contents over time in the leaves of
three hardwood species grown at the Tennessee Division of Forestry
Nursery (Data series reported with standard error)??..????????73
5. Nitrogen, phosphorous, and potassium contents over time in the branches
and stems of three hardwood species grown at the Tennessee Division of
Forestry Nursery (Data series reported with standard error)...??????74
6. Nitrogen, phosphorous, and potassium contents over time in the roots of
three hardwood species grown at the Tennessee Division of Forestry
Nursery (Data series reported with standard error)??.????????.75
1
I. MORPHOLOGICAL AND NUTRITIONAL DEVELOPMENT OF THREE
SPECIES OF NURSERY-GROWN HARDWOOD SEEDLINGS IN
TENNESSEE
INTRODUCTION
Hardwood seedlings grown in forest tree nurseries account for only 3.6% of the
total southern seedling production and are grown in less than half of all tree nurseries in
the region (McNabb and Santos, 2004). However, hardwoods are an important source of
nursery revenue as hardwood seedlings cost around five times more than pine and, on an
area basis, are more valuable (South and Carey, 2004). As a result, hardwood seedling
establishment costs more than pine and good seedling survival is critical to protect this
investment (Grebner et al., 2004).
Despite the higher investment required for hardwood planting, the demand for
hardwood seedlings has held steady over the past several years and may have actually
increased (Barnett, 2002). This increase in seedling demand is likely related to federal
cost share programs, particularly those related to wetland restoration (Matherne, 2002;
Smith, 1999). The demand also resulted in hardwood seedling shortages in the central
hardwood region (Jacobs, 2003). It was estimated that demand outpaced supply in 1999
by 25 to 50 million seedlings with demand expected to rise 20% annually (Jacobs et
2
al., 2004). This increasing demand caused some nurseries to begin producing hardwood
planting stock (Jacobs et al., 2004a) which generated concerns regarding seedling quality.
Nursery managers, who devoted their career to the production of pine seedlings, suddenly
needed to produce hardwoods and they faced a totally different world (Davey, 1994).
Concerns were heightened by poor survival and growth observed in reforestation
programs in the Lower Mississippi River Alluvial Valley (LMRAV) region (Lockhart et
al., 2003). The interest in hardwood seedling establishment increased the need for
hardwood seedling production research (Vanderveer, 2004).
Unfortunately, compared to conifers, there is a limited amount of peer-reviewed
scientific literature for hardwood nursery culture. Most forest tree research has focused
primarily on issues related to conifers. Research on hardwoods is further complicated by
the large number of species produced. Conifers grown in southern nurseries are mostly
from the Pinaceae family, while the common hardwood species are from many families
such as: Aceraceae (Acer), Fagaceae (Castanea and Quercus), Hamamelidaceae
(Liquidambar), Juglandaceae (Carya and Juglans), Magnoliaceae (Liriodendron),
Oleaceae (Fraxinus), Platanaceae (Platanus), and Rosaceae (Prunus)., with each species
having individual cultural requirements (Boyer, 2003).
Although there is much debate among nursery managers and scientists as to the
best methods for growing hardwood seedlings, most nurseries follow general practices
for hardwood seedling nursery production (Jacobs, 2003). Guidelines describing typical
hardwood seedling development have not been published (Gardiner et al., 2002). An
understanding about morphological and nutritional characteristics may lead to the
development of management practices based on rate and periodicity of growth, which
3
may conduct to higher quality seedling production (Thompson, 1985; Vanderveer, 2004).
Morphological targets for the individual species to be grown, as well as guidelines for
different stages of seedling development, need to be better defined.
A fundamental step in documenting ?normal? seedling development is the
periodicity of absorption and translocation of each specific nutrient. This characterization
is needed to identify nutrient requirements and deficiencies as well as avoid negative
environmental effects caused by over-fertilization (Stanturf et al., 2002). Soil nutrient
depletion through crop harvesting and the relationship between plant nutrient
concentration and productivity are needed to manage soil fertility more efficiently (Boyer
and South, 1985).
Hardwood Seedling Culture
In 2003, nurseries in 12 southern states (excluding Kentucky) produced around 39
million hardwood seedlings (McNabb and Santos, 2004). Quercus was the most
important genera accounting for 60% of all hardwood production. A commonly produced
oak species is Nuttall oak (Quercus nuttallii Palmer). It was not distinguished as a species
until 1927 and it has been called red oak, Red River oak, and pin oak (Filer, 1990).
Nuttall oak is a commercially important species that produces heavy annual mast. It
grows well on poorly drained, alluvial clay soils in the first bottoms of the Mississippi
Delta region, performing best on soils with a pH of 4.5 to 5.5. It is common on clay
ridges but is not found in permanent swamps or on well-drained loams. Typically, it
grows on clay flats that are normally covered with 8 to 20 cm of water throughout the
winter (Filer, 1990).
4
The second most common genera produced in southern hardwood nurseries was
Fraxinus, particularly F. pennsylvanica (Marsh), which was 4.7% of all regional
hardwood production. It is also called red ash, swamp ash, and water ash, and is the most
widely distributed of all the American ashes. It grows best on fertile, moist, well-drained
soils, but is probably the most adaptable of all the ashes, growing naturally on a range of
sites (Kennedy, 1990).
The third most commonly produced hardwood species in the South is yellow
poplar (Liriodendron tulipifera L.). A commercially valuable species, it grows on a wide
variety of soil types, avoiding only very wet or very dry sites. Although it will grow on
those sites, it does so poorly. "The best growth usually occurs on north and east aspects,
on lower slopes, in sheltered coves, and on gentle, concave slopes" (Beck, 1990).
Nursery production of hardwood seedlings is different than the production of pine
seedlings in several important ways. Most hardwoods are broadleaved and deciduous,
while most conifers have needlelike leaves and are evergreen. Hardwoods tend to show
more branching, have thicker roots, require higher fertility, and are more susceptible to
pests and diseases when compared to conifers (Tinus, 1978). When compared to pine,
hardwood seedlings need approximately twice the water and significantly more essential
elements and should be grown at lower seedbed densities than pines (Davey, 1994). For
instance, recommended nursery bed densities for oaks are 86-107 (high) and 64-85 (low)
per square meter (Formy-Duval, 1976). Stoeckeler, (1967) found that green ash produced
the highest number of good-quality trees at a density of 134 trees per square meter. Each
nursery has its own method for grading, counting, and bundling seedlings, though most
are somewhat similar (Williams and Hanks, 1994). Normally, hardwood nurseries count
5
individual seedlings for grading (Grieve and Barton, 1960). Bareroot seedlings are grown
in a nursery bed, lifted by undercutting at 20 to 25 centimeters below the soil surface
which mechanically loosens the soil around the roots. They are then graded, and packed
into bags at the nursery to keep the roots moist (Pijut, 2003). Top-pruning may reduce the
costs involved with lifting, bundling, packing, storing, shipping, and planting hardwoods
(South, 1996) and is recommended for species like northern red oak (Johnson et al.,
1986), sycamore (Briscoe, 1969), and for some tropical species (Djapilus, 1990).
Hardwood Seedling Nutrition
Very little is known about the nutrient requirements of relatively important
hardwood species, especially information on optimum nutrient levels, critical ranges for
essential elements, and the physiological effects of nutrient deficiencies (Erdmann et al.,
1979). Most hardwoods develop a pattern of nutrient utilization different from conifers.
Conifers have less than half the annual nutrient requirement of most hardwoods (Lassoie
et al., 1985) because they retain numerous foliage age classes and thus have lower
demand for foliage replacement (Elliot and White, 1993). Hardwood seedlings need 50%
more nitrogen (N) than most pines (Davey, 1994). Knowledge about hardwood
micronutrient nutrition (Stone, 1968) is much less than the macronutrients (Davey, 1994).
Average N uptake for mature hardwood trees is approximately 10 times higher
than P and 3 times that of K. Ca uptake may be higher than N for most hardwoods
(Pritchett and Fisher, 1987) and the ability of a species to respond to a resource level
availability should be related somehow to nutrient use efficiency (Elliott and White,
1993) as nutrient use efficiency generally decreases as the amount of cellulose per
6
seedling increases (Gray and Schlesinger, 1983; Shaver and Melillo, 1984; Birk and
Vitousek, 1986; Lajtha and Klein, 1988).
Fertilizer prescriptions are unique to each nursery, and, to continually grow high
quality seedlings on one nursery site, nutrients must be added to replace those lost when
seedlings are harvested (South and Boyer, 1985). A deficiency occurs when plant
concentrations are so low they limit plant development (Landis et al., 2004). Effective
monitoring and nutrient application prevents the ?hidden hunger? that occurs when plant
nutrients are deficient, yet show no symptoms. Fertilizer application should be based on
soil nutrient analysis, tissue analysis, and stock performance (Triebwasser, 2003). Many
factors impact the effectiveness of nutrient application on hardwood seedling growth.
These factors include when and where fertilizer is applied and availability of nutrients to
the seedling. Before maximum growth response to fertilization can be obtained, the
elements that limit productivity in a given species on a given site must be correctly
diagnosed (Brown, 1999). In particular, the quantities of mineral nutrients required for
maximum growth may differ among hardwoods.
Hardwood Seedling Quality
Many studies have shown that field survival and productivity are related to
planting stock quality (Jaenicke, 1999). Defining the characteristics of a high quality
seedling for each species is important. Another important characteristic of seedling
quality is root collar diameter (Davey, 2005). Bareroot hardwood seedlings should have a
minimum shoot height of 46 centimeters with 61 centimeters preferred (Allen et al.,
2001) and a root collar diameter of at least 7 mm. According to Pijut (2003), some
7
seedlings of oak can be considered optimum when height is 25 to 30 centimeters tall, if
they have good diameter. Initial root collar diameters are good indicators of field
performance of northern red oak (Quercus rubra L.) seedlings (Dey and Parker 1997).
Most seedling grading have concentrated on shoot characteristics with little
attention to root systems. Taproots should be healthy looking, well-developed, have
several lateral roots, and have a minimum root length of 20 to 25 centimeters (Pijut,
2003). Shoot to root ratios are usually based on the mass of roots without consideration
for root morphology. Seedlings should have a low shoot to root ratio. A low ratio ? one
which predicts better survival ? is 1:1 to 1:2 shoot to root ratio (Jaenicke, 1999).
Hardwood seedlings with too much shoot to root volume may die back (Pijut, 2003);
therefore, pruning is an important way of restoring the balance between shoots and roots.
South (1998) stated that for hardwood seedlings less than 50 centimeters tall, there was
no relationship between survival of pruned and non-pruned seedlings.
Height and stem diameter provide the best estimate of seedling performance after
outplanting. For example, diameter in conifers is the best predictor of survival, while
height seems to best predict height growth (Mexal and Landis, 1990). Parameters such as
root mass or number of lateral roots are also useful in assessing potential performance
(Aphalo and Rikala, 2003). Typically generic hardwood seedling quality standards are a
problem. Species-specific standards do not exist, yet it is apparent that each species
presents unique morphological characteristics and considerable morphological variability
between individuals (Jacobs, 2003). Even less is known about species-specific nutritional
demand.
8
This research will attempt to characterize the development of three commonly
grown hardwood species. The temporal morphological growth patterns for several plant
parts will be reported. Nutritional analysis will document nutrient concentration. Content
over time for the various seedlings? morphological parameters, litterfall, mulch inputs,
nutrient uptake, periodicity of absorption, allocation, and translocation will be followed
over the season and used to calculate seedling nutrient use efficiency. This research
should help growers to set parameters for both morphological and nutritional crop
development.
9
REFERENCES
Allen, J.A., Keeland, B.D., Stanturf, J.A., A.F. Clewell, and Kennedy, H.E. Jr. 2001. A
guide to bottomland hardwood restoration. U.S. Geological Survey, Biological
Resources Division Information and Technology Report USGS/BRD/ITR-2000-
0011, U.S. Department of Agriculture, Forest Service, Southern Research Station,
General Technical Report SRS-40, 132p.
Aphalo, P. and Rikala, R. 2003. Field performance of silver-birch planting-stock grown
at different spacing and in containers of different volume. New Forests 25(2): 93-
108.
Barnett, J.P. 2002. Trends in nursery research and production. In: Dumroese, R.K., Riley,
L.E. and Landis, T.D., tech. coord.. National Proceedings: Forest and
Conservation Nursery Associations-1999, 2000, and 2001.Proceedings RMRS-P-
24. Ogden, UT: USDA Forest Service, Rocky Mountain Research Station: 97-
100.
Beck, D.E. 1990. "Liriodendron tulipifera." In: Silvics of North America Vol 2.
Hardwoods. Edited by Burns, R.M. and Honkala, B.H. USDA Forest Service
Agriculture Handbook 654. pp. 405-415.
Birk, E. and Vitousek, P.M. 1986. Nitrogen availability and nitrogen use efficiency in
loblolly pine stands. Ecology, 67: 69-79.
Boyer, D. 2003. Soil and water management plans for bareroot nurseries. In: Riley, L. E.,
Dumroese, R. K., and Landis, T. D., tech. coord.. National proceedings: Forest
and Conservation Nursery Associations?2003; 2003 June; Coeur d?Alene, ID
and Springfield, IL. Proc. RMRS-P-33. Fort Collins, CO: U.S. Department of
Agriculture, Forest Service, Rocky Mountain Research Station.
Boyer, J.N. and South, D.B. 1985. Nutrient content of nursery grown loblolly pine
seedlings. Ala. Agr. Exp. Sta. Circular 282, Auburn University, Alabama. 27 p.
Briscoe, C.B. 1969. Establishment and early care of sycamore plantations. Res. Pap. SO-
50. New Orleans: USDA Forest Service, Southern Forest Experiment Station. 18
pp.
Brown, K.R. 1999. Mineral nutrition and fertilization of deciduous broadleaved tree
species in British Columbia. B.C. Min. For. Res. Prog. Work. Pap. n. 42. 52 p.
[Online WWW]. Available URL:
?http://www.for.gov.bc.ca/hfd/pubs/Docs/Wp/Wp42.htm? [Accessed 16
September 2005].
10
Davey, C.B. 1994. Soil fertility and management for culturing hardwood seedlings. Pages
38-49. In: Landis, T.D. and Dumroese, R.K., tech cords. National Proceedings:
Forest and Conservation Nursery Associations. Fort Collins, Colorado: USDA
Forest Service Rocky Mountain Forest and Range Experiment Station General
Technical Report RM-257.
Davey, C.B. 2005. Hardwood seedling nutrition. In: Dumroese, R. K., Riley, L. E., and
Landis, T. D., tech. coords. 2005. National proceedings: Forest and Conservation
Nursery Associations?2004; 2004 July; Charleston, NC; and 2004 July;
Medford, OR. Proc. RMRS-P-35. Fort Collins, CO: U.S. Department of
Agriculture, Forest Service, Rocky Mountain Research Station.
Demirsoy, L. and Demirsoy, H. 2003. Leaf area estimation model for some local cherry
genotypes in Turkey. Pakistan Journal of Biological Sciences. 6(2): 153-156.
Dey, D.C. and Parker, W.C. 1997. Morphological indicators of stock quality and field
performance of red oak (Quercus rubra L.) seedlings underplanted in a central
Ontario shelterwood. New Forests 14(2): 145-156.
Djapilus, A. 1990. Pruned bare rooted seedlings and prospects for their use in industrial
plantation forest management. Duta-Rimba 16:119-120. Indonesia.
Elliott, K.J. and White, A.S. 1993. Effects of competition from young northern
hardwoods on red pine seedling growth, nutrient use efficiency, and leaf
morphology. For. Ecol. Manage., 57: 233-255.
Erdmann, G.G., Frederick T.M., and Robert R. O. 1979. Macronutrient deficiency
symptoms in seedlings of four northern hardwoods. USDA Forest Service,
General Technical Report NC-53. North Central Forest Experiment Station, St.
Paul, MN. 36 p.
Filer, T.H. 1990. ?Quercus nuttallii?. In: Burns, R. M. and Honkala, B. H. Silviculture
of North America: 1. Conifers; 2. Hardwoods. Agriculture Handbook 654. U.S.
Department of Agriculture, Forest Service, Washington, DC. Vol 2. 877 p.
Formy - Duval, J.G. 1976. Tree handling, seedling size, and seeding costs. In
Proceedings, Hardwood Short Course. N. C. State- Industry Cooperative. Tree
Improvement and Hardwood Research Programs, North Carolina State
University, Raleigh, pp. 60-62.
11
Gardiner, E.S., Russell, D.R., Oliver, M., and Dorris, L.C. 2002. Bottomland hardwood
afforestation: state of the art. In: Holland, M.M., Warren, M.L., and Stanturf, J.A.,
editors. Proceedings of a conference on sustainability of wetlands and water
resources: how well can riverine wetlands continue to support society into the
21st century? Asheville (NC): USDA Forest Service, Southern Research Station.
General Technical Report SRS-50. pp. 75-86.
Gray, J.T. and Schlesinger, W.H. 1983. Nutrient use by evergreen and deciduous shrubs
in Southern California. J. Ecol., 71: 43-56.
Grebner, D.L., Ezell, A.W., Gaddis, D.A., and Bullard, S.H. 2004. How are investment
returns affected by competition control and southern oak seedling survival? Gen.
Tech. Rep. SRS?71. Asheville, NC: U.S. Department of Agriculture, Forest
Service, Southern Research Station. pp. 547-550.
Grieve, W.G. and Barton, J.H. 1960. Operations guide for TVA nurseries. Tenn. Val.
Auth., Norris, Tenn. 51p.
Jacobs, D.F. 2003.Nursery production of hardwood seedlings. Purdue University
Cooperative Extension Service, FNR-212, 8 p.
Jacobs, D.F., Gardiner, E.S., Salifu, K.F., Overton, R.P., Hernandez, G., Corbin, B.E.,
Wightman, K.E., and Selig, M.F. 2004a In press. Seedling quality standards for
bottomland hardwood afforestation in the Lower Mississippi River Alluvial
Valley: Preliminary results. In: Dumroese, R. K., Riley, L. E., and Landis, T. D.,
tech. coords. 2005. National proceedings: Forest and Conservation Nursery
Associations?2004. Proc. RMRS-P-35. Fort Collins, CO: U.S. Department of
Agriculture, Forest Service, Rocky Mountain Research Station. 142 p.
Jacobs, D.F., Wilson, B.C., and Davis, A.S. 2004b. Recent trends in hardwood seedling
quality assessment. In: Dumroese, R.K., Riley, L.E., and Landis T.D., tech.
coord.. National Proceedings: Forest and Conservation Nursery Associations-
2003. Ogden, UT: USDA Forest Service, Rocky Mountain Research Station.
Proceedings RMRS-P. 33:140-144.
Jaenicke, H. 1999. Good tree nursery practices. International centre for research in
agroforestry. Research nurseries. CRAF, Nairobi, Kenya. 83 pp. [Online WWW].
Available URL:
?http://www.worldagroforestry.org/NurseryManuals/Research/Title.pdf?
[Accessed 18 September 2005].
Johnson, P.S., Dale, C.D., Davidson, K.R., and Law, J.R. 1986. Planting northern red oak
in the Missouri Ozarks: a prescription. Northern Journal of Applied Forestry 3:66-
68.
12
Kennedy, H.E. 1990 Silviculture of North America: 1. Conifers; 2. Hardwoods. In:
Burns, R.M., and Honkala, B.H. Agriculture Handbook 654. U.S. Department of
Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.
Lajtha, K. and Klein, M. 1988. The effect of varying nitrogen and phosphorus availability
on nutrient use by Larrea tridentata, a desert evergreen shrub. Oecologia, 75:
348-353.
Landis, D.T., Haase, D.L., and Dumroese, R.K. 2004. Plant nutrient testing and analysis
in forest and conservation nurseries. In: Dumroese, R. K., Riley, L. E., and
Landis, T. D., tech. coords. 2005. National proceedings: Forest and Conservation
Nursery Associations?2004; 2004 July; Charleston, NC; and 2004 July;
Medford, OR. Proc. RMRS-P-35. Fort Collins, CO: U.S. Department of
Agriculture, Forest Service, Rocky Mountain Research Station. 142 pp.
Lassoie, J.P., Hinckley, T.M., and Grier, C.C. 1985. Coniferous forest of the pacific
northwest. In: Chabot, B.F. and Mooney, H.A., eds. Physiological Ecology of
North American Plant Communities. New York: Chapman & Hall.
Lockhart, B.R., Keeland, B., Mccoy J., and Dean, T.J. 2003.Comparing regeneration
techniques for afforesting previously farmed bottomland hardwood sites in the
Lower Mississippi Alluvial Valley, USA Forestry, vol. 76, iss. 2, pp. 169-180.
Oxford University Press.
Matherne, C. 2002. Propagating hardwood seedlings in Louisiana. In: National nursery
proceedings - 1999, 2000, and 2001. pp.234-235.
May, J. T. 1984. Seedling, quality, grading, culling and counting. Chapter 9. Southern
Pine Nursery Handbook. USDA Forest Service Southern Region.
McNabb, K. and Santos, H.Z. 2004. A survey of forest tree seedling production in the
south for the 2003-2004 planting season. Southern Forest Nursery Management
Cooperative, Technical Note 04-02. Auburn University. Auburn, AL.
Mexal, J.G. and Landis, T.D. 1990. Target seedling concepts: height and diameter. In:
Rose R, Campbell SJ, Landis TD, eds. Target Seedling Symposium: Proceedings,
Combined Meeting of the Western Forest Nursery Associations. USDA Forest
Service, Rocky Mountain Forest and Range Experiment Station. pp. 17-35.
Noriyuki. O. and Hiroshi T. 2003. Branch architecture, light interception and crown
development in saplings of a plagiotropically branching tropical tree, Polyalthia
jenkinsii (Annonaceae). Annals of Botany. 91:55-63.
Pijut, P.M. 2003 Planting and care of fine hardwood seedlings: Planting hardwood
seedlings in the Central Hardwood Region.FNR-210. Purdue University
Department of Forestry and Natural Resources, West Lafayette, Indiana. 8 p.
13
SAS Institute. 1999-2001. SAS user?s guide: Statistics. Version 9.1. SAS Institute, Inc.,
Cary, NC.
Schultz, R.C. and Thompson, J.R. 1996. Effect of density control and undercutting on
root morphology of 1+0 bare-root hardwood seedlings:five-year field
performance of root-graded stock in the central USA. New Forests 13: 297-310.
Shaver, G.R. and Melillo, J.M. 1984. Nutrient budgets of marsh plants: efficiency
concepts and relation to availability. Ecology, 65: 1491-1510.
Shoulders, E. 1960. Seedbed density influences production and survival of loblolly and
slash pine nursery stock. Tree Planter's Notes 42:19-21.
Smith, D.M. 1999. Hardwood seedlings as an alternative crop for small farms.
agricultural marketing outreach workshop Training Manual. USDA. Memphis,
TN. April 11-13, 2000
Snee, R.D. and Pfeifer, C.G. 1983. Encyclopedia of Statistical Sciences. New York: John
Wiley & Sons, Inc. 3: p. 635
South, D.B. 1996. Top-pruning bareroot hardwoods: a review of the literature. Tree
Planters Notes 47(1):34-40.
South, D.B. 1998. Effects of top-pruning on survival of southern pines and hardwoods..
In Proc., 9th Biennial S. Silv. Res. Conf. USDA For. Serv. Gen. Tech. Rep. SRS-
20. pp. 3-8.
South, D.B. and Carey A.W. 2005. Weed control in bareroot hardwood nurseries. pp. 34-
38. In: Dumroese, R. K., Riley, L. E., and Landis, T. D., tech. coords. 2005.
National proceedings: Forest and Conservation Nursery Associations-2004; 2004
July; Charleston, NC and Medford, OR. Proc. RMRS-P-35. Fort Collins, CO:
U.S. Department of Agriculture, Forest Service, Rocky Mountain Research
Station. 142 p.
Stanturf, J.A., van Oosten, C., Netzer, D.A., Coleman, M.D., and Portwood, C.J. 2001.
Ecology and silviculture of poplar plantations. In: Dickmann, D.I., Isebrands,
J.G., Eckenwalder, J.E., and Richardson, J. (Eds.), Poplar Culture in North
America. National Research Courcil, Ottawa, Canada, pp. 153?206.
Stoeckeler, J.H. 1967. Seedbed density affects size of 3-0 green ash nursery stock.
Research Note NC-25. St. Paul, MN: U.S. Dept. of Agriculture, Forest Service,
North Central Forest Experiment Station
14
Stone, E.L. 1968. Micronutrient nutrition of forest trees: A review. In: Forest fertilization,
theory and practice. Tenn. Valley Authority, Nat. Fert. Dev. Center: Muscle
Shoals, Alabama. pp. 132-75.
Terrell, G.R. and Scott, D.W. 1985, "Oversmoothed nonparametric density estimates."
Journal of the American Statistical Association, 69: 730- 737.
Thompson, B.E. 1985. Seedling morphological evaluation - What you can tell by
looking. In: Duryea, M.L. (Editor) Evaluating Seedling Quality: Principles,
procedures, and predictive abilities of major tests. Forest Research Laboratory,
Oregon State University, Corvallis.
Thompson, J.R. and Schultz R.C. 1995. Root system morphology of Quercus rubra L.
planting stock and 3-year field performance in Iowa. New Forests 9: 225-236.
Tinus, RW. 1978. Production of container-grown hardwoods. Tree Planters? Notes 29:3-
9.
Triebwasser, M.E. 2003. Fertilizer application: balancing precision, efficacy, and cost. In:
Riley, L. E., Dumroese, R. K., and Landis, T. D., tech. coord.. National
proceedings: Forest and Conservation Nursery Associations?2003; 2003 June;
Coeur d?Alene, ID and Springfield, IL. Proc. RMRS-P-33. Fort Collins, CO: U.S.
Department of Agriculture, Forest Service, Rocky Mountain Research Station.
Vanderveer, L. 2004. Survey of root and shoot cultural practices for hardwood seedlings.
Pp. 21-25. Dumroese, R. K., Riley, L. E., and Landis, T. D., tech. coords. 2005.
National proceedings: Forest and Conservation Nursery Associations?2004;
2004 July; Charleston, NC and Medford, OR. Proc. RMRS-P-35. Fort Collins,
CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research
Station. 142 p.
Ward, J.S., Martin, P.N.G., and Stephens, G.R. 2000. Effects of planting stock quality
and browse protection-type on height growth of northern red oak and eastern
white pine. For. Ecol. and Mgt. 127: 205-216.
Williams, R.D. and Hanks, S.H. 1994. Hardwood nursery guide. U.S. Department of
Agriculture, Agriculture Handbook 473. 78p.
15
II. MORPHOLOGICAL DEVELOPMENT OF THREE SPECIES OF NURSERY-
GROWN HARDWOOD SEEDLINGS IN TENNESSEE
ABSTRACT
We followed the morphological development of three common hardwood species
growing under typical cultural practices in a southern hardwood nursery. The seasonal
development of morphological parameters were compared. Yellow poplar was by far the
largest seedling at the end of the season, followed by Nuttall oak and green ash. Seasonal
periodicity of morphological development varied by species, indicating that similar
nursery practices may affect species differently. Several parameters, such as the
development of first order lateral roots, occurred at the same time. Large increases in
lateral root weight occurred in late fall. Coefficients of variations for the morphological
components over time were high for all three species and most parameters. All three
hardwood species had strong correlations between root collar diameter (RCD) and many
other morphological parameters, including number of first order lateral roots.
16
INTRODUCTION
Hardwood seedlings grown in southern tree nurseries correspond to 3.6% of the
total seedling production and are grown in less than half of tree nurseries in the region
(McNabb and Santos, 2004). However, hardwood crops are an important source of
nursery revenue since on an area basis they are more valuable than a pine crop (South and
Carey, 2004). In fact, the demand for nursery production of hardwood species has held
steady over the past several years and may have actually increased (Barnett, 2002) due to
federal cost share programs, particularly those related to wetland restoration (Smith,
1999; Matherne, 2002).
Morphological measurements are commonly used as a predictor for the field
performance of hardwood seedlings (Wilson and Jacobs, 2004). Parameters such as shoot
height, root collar diameter (RCD), root volume, and number of first order lateral roots
have been used with moderate success (Thompson and Schultz, 1995; Ward et al., 2000;
Jacobs and Seifert, 2004). For example, hardwood seedlings with a greater quantity of
first order lateral roots (>1mm) were found to survive better (Jacobs and Seifert, 2004)
and seedlings with large root collar diameters and tall shoots exhibited improved field
performance (Dey and Parker, 1997). Unfortunately, compared to conifers, there is a
limited amount of peer-reviewed scientific literature for hardwood nursery culture
(Gardiner et al., 2002) and the literature is generally deficient in hardwood seedling
quality research (Wilson and Jacobs, 2004).
Each hardwood species possess unique morphological characteristics. Several
quality assessment approaches are likely needed to understand variability in hardwood
17
seedling morphology. For example, a poor quality black walnut (Juglans nigra L.)
seedling may have more large lateral roots than a good quality white oak (Quercus alba
L.) seedling. In addition, nursery related morphological variability may persist in the field
many years after planting (Wightman, 1999). Thus, it is helpful to understand the general
morphological character of each species of interest (Jacobs, 2003).
This study was conducted at the Tennessee Division of Forestry (TDF), East
Tennessee Nursery in Delano, Tennessee. The TDF produces approximately ten million
seedlings annually, with hardwood production close to two million seedlings. Currently,
28 hardwood species are grown at this nursery with yellow poplar, green ash, and various
oaks produced in the largest numbers. Winter-sown Nuttall oak (Quercus nuttallii
Palmer), spring-sown green ash (Fraxinus pennsylvanica Marsh), and yellow poplar
(Liriodendron tulipifera L.) were selected for this study as they are routinely grown by
the TDF and are commonly produced in southern hardwood nurseries (McNabb &
Santos, 2004). The objective of this research was to describe the morphological
development of three common hardwood species when grown under typical cultural
practices in a southern hardwood nursery. There are three hypotheses to test:
1: Seedling morphology and development are distinct and unique for the three
species measured
2: Morphological variability is affected by species
3: RCD is the best single morphological parameter to predict overall seedling
morphology for the three species
18
MATERIALS AND METHODS
Nursery location and Culture
This study was conducted at the Tennessee Division of Forestry (TDF), nursery in
Delano, Tennessee. A mixed lot of Nuttall oak (209 seeds/kg, 100% germination, 60%
expected seed efficiency) was sown on March 1
st
using a NB-2 sower and a 107 seeds/m
2
sowing density. A total of 3,316 linear bed meters was sown. A mixed lot of yellow
poplar (43% germination, 100% purity, 80% expected seed efficiency) was sown on
April 18
th
using a NB-2 sower at a target spacing of 247 seeds/m
2
. Seeds were stratified
for 90 days prior to sowing. A total of 3,332 linear bed meters were sown. A mixed lot of
green ash (76% germination, 100% purity, 60% expected feed efficiency) was sown on
April 18
th
using a NB-2 sower at a target sowing density of 141 seeds/m
2
. Seeds were
stratified for 90 days prior to sowing. A total of 2,182 linear bed meters was sown.
Cultural practices
A total of 287 kg/ha elemental nitrogen (N) was applied as top dressing for
Nuttall oak between May 6 and September 23 in eight applications (Table 1). Elemental
phosphorus was applied at 50 kg/ha in two applications. A directed spray of 2 ml/L
glyphosate was applied on May 11 to control weeds. Oxyfluorfen (Goal 4F
?
) was applied
at 280 grams/ha on July 29. The insecticide diazinon was applied at 2.3 kg/ha as a
directed spray on August 19.
A total of 234 kg/ha elemental N was applied as top dressing for yellow poplar
between May 6 and August 4 in seven applications (Table 1). Elemental phosphorus was
19
applied at 87 kg/ha in three applications. A directed spray of 20 ml/L glyphosate was
applied on May 5 and June 28 to control weeds. The selective herbicide napropamide
(Devrinol
?
) was applied at 2.25 kg/ha as a directed spray on August 16.
A total of 217 kg/ha elemental N was applied as top dressing to green ash
between May 6 and August 4 in six applications (Table 1). Elemental phosphorus was
applied at 25 kg/ha in a single application. A directed spray of 20 ml/L glyphosate was
applied on May 11 and June 29 to control weeds. The herbicide sethoxydim (Poast
?
) was
applied at 413 g/ha on May 25.The insecticide diazinon was applied at 2.3 kg/ha as a
directed spray on August 19.
Sampling Design
All three species were periodically sampled from 6 blocks in three separate beds.
Each block was one bed wide and 4.87 m long, for a total length of 29.2 m. Seedlings
were sampled within blocks in the months of May, July, September, and November using
a 0.3 m x 1.22 m counting frame. Sample plots were randomly distributed within the
block, with 0.91 m buffers between them. To carefully harvest as much of the root system
as possible, seedlings were sampled using a shovel except on the last sampling time when
a tractor drawn undercutting blade lowered to around 33 cm deep lifted the seedlings and
then loosened the soil from around the roots. All seedlings were taken to laboratory
facilities in Auburn for analysis.
20
Table 1. Elemental fertilizer application for three hardwood species grown at the
Tennessee Division of Forestry, East Tennessee Nursery.
Species Date N kg/ha P kg/ha Product
Nuttall oak May6
39 -
Ammonium nitrate
June 2
39 -
Ammonium nitrate
June 21
22 25
Diammonium phosphate
July 20
39 -
Ammonium nitrate
July 29
39 -
Ammonium nitrate
August 4
22 25
Diammonium phosphate
August
39 -
Ammonium nitrate
September 23
48 -
Ammonium nitrate
Total
287 50
Yellow poplar May 6
39 -
Ammonium nitrate
June 2
39 -
Ammonium nitrate
June 21
22 25
Diammonium phosphate
July 20
34 37
Ammonium nitrate
July 29
39 -
Ammonium nitrate
August 4
22 25
Diammonium phosphate
August
39 -
Ammonium nitrate
Total
234 87
Green ash May 6
39 -
Ammonium nitrate
June 2
39 -
Ammonium nitrate
June 21
22 25
Diammonium phosphate
July 20
39 -
Ammonium nitrate
July 29
39 -
Ammonium nitrate
August 4
39 -
Ammonium nitrate
Total
217 25
Measurements
Seedling height, root collar diameter (RCD), number of first order branches
(FOB), number of first order lateral roots (FOLR) (>1 mm) and number of leaves were
tallied. Fresh and dry weights were obtained for stem, taproot, FOLR, FOB, and leaves
on a plot basis. Average seedling values for these variables were calculated by dividing
21
plot values by the number of seedlings sampled. The root/shoot ratio was based on
average seedling dry weights.
Average seedling foliar area was estimated by first measuring approximately 30
randomly selected leaves from each plot using a LICOR 3100C Leaf Area Meter. The
average area per leaf was multiplied by the average number of leaves per seedling to
calculate an average seedling leaf area by plot.
Analysis
Statistical analyses were performed using SAS version 9.1 (SAS Institute, Cary,
NC). Individual seedling values were used to calculate averages for height, RCD, number
of FOB and FOLR, and number of leaves. Average values were obtained for each
seedling component at each sampling time. Linear regressions were employed to explore
the relationship between the morphological parameters from July, September, and
November data. Analyses involving dry weight data were based on average plot values
per seedling.
22
RESULTS
Nuttall Oak
Nuttall oak grew to an average RCD of 9.9 mm and 57.7 cm height, with 9.3 first
order lateral roots, and 6.8 first order branches by November, eight months after sowing
(Table 2). Seedlings sampled in September, prior to the beginning of autumn leaf fall,
averaged 64 leaves and 1,385 cm
2
leaf surface area. The periodicity of morphological
development was not uniform across all components. The largest increases in RCD and
FOLR occurred from September to November with 36% and 71%, of total RCD and
FOLR growth occurring in this period, respectively. Interestingly, RCD showed its
lowest growth from July to September, at a time when many seedling parameters are
growing fastest. Leaf area and height, for example, grew 65% and 34%, respectively, of
their total growth from July to September. From July to September the average number of
leaves per seedling increased from 41.5 to 64, an increase of 54%. At the same time
average leaf area per seedling increased from 494 to 1,385 cm
2
, an increase of 192%.
Interestingly, average Nuttall oak height increased 17% from September to November.
Average seedling dry weight increased throughout the season, including 101%
and 112% increases in stem and tap root dry weights, respectively, from September to
November. The dry weight of FOLR increased nearly 400% from September to
November. This increase in root mass impacted the root/shoot ratio which increased from
0.07 to 0.82 during this period. Extended and unexpected warm temperatures in October
and November may have delayed leaf fall, resulting in a drop of only 34% of leaf dry
weight in the November sample.
23
Seedling Morphological Variability
Variability between seedlings was high for all parameters, with Coefficients of
Variation (CV) ranging from 21% to 46% for RCD and 29% to 44% for shoot height.
The number of first order lateral roots was particularly highly variable. Seedling
variability may have increased, decreased or remained the same over the sample period.
It appeared there was little change for several variables such as RCD, height, first order
branch weight, and root/shoot ratio. The number of leaves, however, was the only
variable showing a strong tendency to increase in variability over time. The CV?s for
NFOLR, leaf area, and the variables related to the dry weights all decreased through the
fall. On the other hand, CV?s were highest for these variables in July, then declined
through the rest of the growing season.
Correlations between Seedling Morphological Parameters
RCD is one of the easiest morphological parameters to measure and is widely
used as an indicator of morphological development. The RCD of Nuttall oak is highly
correlated (R
2
>0.70) with 3 out of 13 other morphological variables (Table 3). RCD was
a good predictor of height, NFOLR, and leaf area. Interestingly, height appears to
correlate better than RCD with weight variables. Height is highly correlated (R
2
>0.70)
with 11 out of 13 other morphological variables with a very good prediction for stem
weight and total shoot weight. The number of leaves correlated well with height but not
(0.47) with RCD. Leaf area correlated strongly with RCD and with all weight variables
except lateral root weight. One of the highest R
2
values (0.78) for morphological
24
variables was found between the number of first order lateral roots and RCD, however,
that was the only strongly correlated variable for lateral roots. All weight variables
related well to height but very poorly with number of first order branches which appears
to be the variable with the smaller potential for correlation. The total stem weight of
Nuttall oak is strongly correlated (R
2
>0.70) with 8 out of 13 other morphological
variables. STEM was a good predictor of RCD, NL, and NFOB.
25
Table 2. Average value for morphological parameters of Nuttall oak seedlings
sampled on specific dates at the Tennessee Division of Forestry Nursery (Coefficient
of variation in parenthesis).
May July September November
N 67 162 226 176
RCD (mm) 2.8 4.9 6.3 9.9
(21%) (35%) (46%) (40%)
Shoot Height (cm) 13.4 27.8 47.4 57.7
(29%) (34%) (42%) (44%)
N
o
of Leaves 7.9 41.5 64 0
(37%) (73%) (84%) -
N
o
of First Order Lateral Roots 0 1.2 2.7 9.33
- (175%) (148%) (86%)
N
o
of First Order Branches 4.8 5.1 6.7 6.8
(48%) (80%) (99%) (75%)
Leaf Area (cm
2
) 94.5 473.7 1385.0 -
(28%) (32%) (17%) -
Dry Weight (g/seedling)
Leaves 0.275 1.67 4.22 2.76
(32%) (34%) (14%) (14%)
First Order Branches 0.0033 0.3 0.96 1.72
(158%) (51%) (23%) (22%)
Stem 0.175 1.12 5.28 10.62
(16%) (44) (35%) (17%)
Tap Root 0.3383 1.41 5.14 10.92
(14%) (30%) (22%) (20%)
First Order Lateral Roots 0 0.05 0.31 1.55
- (102%) (51%) (18%)
Total Shoot 0.4517 3.08 10.46 15.09
(24%) (39%) (23%) (13%)
Total root 0.3383 1.46 5.45 12.47
(14%) (30%) (20%) (19%)
Total dry mass 0.7933 4.54 15.91 27.55
(15%) (34%) (21%) (14%)
Root/Shoot ratio 0.7 0.49 0.52 0.82
(37%) (22%) (13%) (16%)
26
T
a
bl
e 3.
R
2
va
l
u
e
s
f
o
r
r
e
g
r
e
s
s
i
o
n
s
be
t
w
e
e
n ba
r
e
r
o
o
t
N
u
t
t
a
l
l
O
a
k
s
e
e
d
l
in
g
m
o
r
p
ho
l
o
g
i
c
a
l
va
r
i
a
b
l
e
s
s
a
mp
l
e
d
f
r
o
m
J
u
ly
t
o
E
a
s
t
T
e
nne
s
s
e
e
N
u
r
s
e
r
y
a
t
D
e
l
a
no
,
T
N
(n
=
5
6
4
).
(
C
o
d
e)
H
T
RCD
NL
NL
R
L
A
N
F
OB
L
V
F
O
B
S
T
T
A
P
F
OL
R
ST
No
ve
mb
e
r
a
t
t
h
e
E
M
ROOT
T
OT
H
e
i
g
h
t
0
.
7
1
0.70
0.61
0
.
8
4
0.57
0.93
0
.
8
3
0
.
8
8
0.80
0.71
0
.
9
4
0.82
0.91
Pr >
F
HT
?
<
.
0
1
<.01
<.01
<.0
1
<.01
<.01
<
.
0
1
<
.
0
1
<.01
<.01
R
C
D
0.71
0.47
0.78
0
.
6
2
0.69
0.70
0
.
6
4
0
.
5
5
0.60
0.64
Pr >
F
RC
D
<.01
?
<
.
0
1
<.01
<.0
1
<.01
<.01
<
.
0
1
<
.
0
1
<.01
<.01
N
o
.
o
f
L
e
a
v
e
s
0.70
0
.
4
7
0.39
0
.
6
5
0.65
0.
80
0
.
8
2
0
.
4
8
0.57
0.23
Pr >
F
NL
<.01
<.
01
?
<.01
<.0
1
<.01
<.01
<
.
0
1
<
.
0
1
<.01
<.01
No
.
o
f
F
O
LR
1
0.61
0
.
7
8
0.39
0
.
5
4
0.41
0.64
0
.
5
8
0
.
4
8
0.58
0.67
Pr >
F
NL
R
<.01
<.
01
<.01
?
<.0
1
<.01
<.01
<
.
0
1
<
.
0
1
<.
01
<.01
L
e
a
f
A
r
e
a
0.84
0
.
6
2
0.65
0.54
0.48
0.91
0
.
8
9
0
.
8
3
0.91
0.50
Pr >
F
LA
<.01
<.
0
1
<.01
<.01
?
<.01
<.01
<.
01
<.
01
<.01
<.01
No
.
o
f
F
OB
2
0.57
0
.
6
9
0.65
0.41
0
.
4
8
0.61
0
.
6
6
0
.
4
0
0.40
0.24
Pr >
F
NF
O
B
<.01
<
.
0
1
<.01
<.01
<.0
1
?
<.01
<
.
0
1
<
.
0
1
<.01
<.01
Dr
y
Weig
h
t
(n
=
9
0
)
L
e
a
v
e
s
0.93
0
.
7
0
0.80
0.64
0
.
9
1
0.61
0
.
9
5
0
.
8
3
0.90
0.56
<
.
0
1
<.01
<.01
0
.
6
4
0.62
0.64
<
.
0
1
<.01
<.01
0
.
6
4
0.57
0.62
<
.
0
1
<.01
<.01
0
.
5
7
0.61
0.59
0
.
0
5
<.01
0.03
0
.
9
1
0.92
0.92
<.
01
<.01
<.01
0
.
5
2
0.41
0.48
<
.
0
1
<.01
<.01
0
.
9
5
0.91
0.95
Pr >
F
LV
<.
01
<
.
0
1
<.01
<.01
<.0
1
<.01
?
<
.
0
1
<
.
0
1
<.01
<.01
FO
B
<
.
0
1
<.01
<.01
F
O
B
0.83
0
.
6
4
0.82
0.58
0
.
8
9
0.66
0.
95
0
.
7
3
0.87
0.40
0
.
8
7
0.86
0.88
Pr >
F
<.
01
<
.
0
1
<.01
<.01
<.0
1
<.01
<.
0
1
?
<.
0
1
<.01
0.02
<.
0
1
<.01
<.01
St
em
0.88
0
.
5
5
0.48
0.48
0
.
8
3
0.40
0.
83
0
.
7
3
0.86
0.71
0
.
9
6
0.88
0.95
Pr >
F
ST
<.
01
<
.
0
1
<.01
<.01
<.0
1
<.01
<.
0
1
<
.
0
1
?
<.01
<.01
<
.
0
1
<.01
<.01
Tap
r
o
o
t
0.80
0
.
6
0
0.57
0.58
0
.
9
1
0.40
0.90
0
.
8
7
0
.
8
6
0.53
0
.
9
2
0.99
0.96
Pr >
F
TA
P
<.01
<
.
0
1
<.01
<.01
<.0
1
<.01
<.
0
1
<
.
0
1
<
.
0
1
?
<.01
<
.
0
1
<.01
<.01
F
O
L
R
0.71
0
.
6
4
0.23
0.67
0
.
5
0
0.24
0.
56
0
.
4
0
0
.
7
1
0.53
0
.
7
1
0.53
0.66
Pr >
F
FO
L
R
<.01
<
.
0
1
<.01
<.01
<.0
1
<.01
<.
0
1
0
.
0
2
<
.
0
1
<.01
?
<
.
0
1
<.01
<.01
27
TA
B
L
E
3
. C
o
ntinue
d
.
To
t
a
l
(
C
o
d
e)
H
T
RCD
NL
NLR
L
A
N
F
OB
L
V
F
O
B
ST
T
A
P
F
O
L
R
ST
E
M
ROOT
T
O
T
St
em
0.94
0
.
6
4
0
.
6
4
0.57
0.91
0.52
0.
95
0
.
8
7
0
.
9
6
0.92
0.71
0
.
9
3
0.99
Pr
>
F
STEM
<.01
<.
0
1
<.
0
1
0.05
<.01
<.01
<.01
<
.
0
1
<
.
0
1
<.01
<.01
?
<.
0
1
<.01
R
o
ot
0.82
0
.
6
2
0
.
5
7
0.61
0.92
0.41
0.
91
0
.
8
6
0
.
8
8
0.99
0.53
0
.
9
3
0.93
Pr
>
F
ROOT
<.01
<
.
0
1
<
.
0
1
<.01
<.01
<.01
<.01
<
.
0
1
<
.
0
1
<.01
<.01
<
.
0
1
?
<.01
Se
e
d
l
i
n
g
TO
T
0.91
0
.
6
4
0
.
6
2
0.59
0.92
0.48
0.95
0
.
88
0.
95
0
.
9
6
0
.
6
6
0.
99
0.
93
?
Pr
>
F
<.01
<.
0
1
<.
0
1
0.03
<.01
<.01
<.01
<.
01
<.
01
<
.
0
1
<
.
0
1
<.
01
<
.
01
?
A
l
l
v
a
r
i
ab
le
s
w
e
r
e
po
s
itiv
e
l
y
co
r
r
e
l
a
te
d
1
F
i
r
s
t O
r
d
e
r
L
a
te
r
a
l R
o
o
t
s
2
F
i
r
s
t
O
r
d
e
r
B
r
an
ch
es
28
Yellow Poplar
Yellow poplar seedlings grew to an average of 12.0 mm RCD and 97.2 cm height
by November, seven months after sowing in April (Table 4). While most RCD and Shoot
height (63% of final growth) development occurred from July through September, the
highest production of leaves occurred from May through July. Fewer leaves were
produced after July yet foliar area increased by a large amount, indicating that leaf
expansion was occurring as opposed to the addition of new leaves. The highest
accumulation of leaf biomass occurred during the months of July and September when
93% of total leaf dry weight was added. During the same period FOB weight also added
93% of its maximum dry weight. Stem dry weight and tap root dry weight increased
similarly with significant increases during the growing season with little or no gain from
September to November. Interestingly, FOLR dry weight increased by nearly 400%
during September to November. This increase in root mass impacted the root/shoot ratio
which increased from 0.2 to 1.0 during this period.
Seedling Morphological Variability
As indicated by the coefficient of variation, seedling morphological variability
may have increased, decreased or remained the same over the nursery season. It appeared
there was little change for several variables such as RCD, height, first order branch
weight, first order lateral root weight, total shoot weight, and root/shoot ratio. Variables
related to leaves, however, showed a strong tendency to increase in variability over time.
The CV for the number of leaves, leaf area, and leaf weight all increased during the
29
growing season. On the other hand, the CV?s for variables, such as the number of first
order lateral roots, dropped over the growing season.
Correlations between Morphological Parameters
All variables seem to correlate strongly between each other with few exceptions.
The RCD of yellow poplar is strongly correlated (R
2
>0.70) with 12 out of 13 other
morphological variables (Table 5). RCD was a good predictor for all variables including
total seedling weights. RCD was very strongly correlated to FOLR (R
2
= 0.90 prob.
F<0.01). The only variable not well correlated with RCD was leaf area which correlated
poorly with all variables. Height followed the same pattern and correlated well with 12
out of 13 morphological variables.
30
Table 4. Average value for morphological parameters of yellow poplar seedlings
sampled on specific dates at the Tennessee Division of Forestry Nursery
(Coefficient of variation in parenthesis).
May July September November
N 196 158 152 147
RCD (mm) 1.1 4.1 9 12
(18%) (39%) (41%) (37%)
Shoot Height (cm) 1.8 33.1 89.3 92.2
(28%) (37%) (35%) (32%)
N
o
of Leaves 3.3 10.3 16.2 0
(21%) (43%) (75%) -
N
o
of First Order Lateral Roots 0 2.4 9.6 23.1
- (129%) (71%) (52%)
N
o
of First Order Branches 0 7.1 11.5 2.8
- (37%) (57%) (96%)
Leaf Area (cm
2
) 2.4 597.3 2794 0
(20%) (21%) (29%) -
Dry Weight (g/seedling)
Leaves 0.0098 1.44 20.36 0
(16%) (21%) (24%) -
First Order Branches
0 0.15 2.24 1.13
- (35%) (27%) (30%)
Stem
0.0017 0.99 19.96 18.98
(29%) (38%) (24%) (20%)
Tap Root
0.0042 0.44 8.14 8.72
(52%) (23%) (35%) (26%)
First Order Lateral Roots
0 0.12 2.4 11.55
- (30%) (38%) (30%)
Total Shoot
0.0112 2.59 42.55 20.11
(17%) (27%) (20%) (18%)
Total root
0.0042 0.56 10.54 20.27
(52%) (23%) (32%) (21%)
Total dry mass
0.0153 3.14 53.09 40.38
(25%) (25%) (21%) (18%)
Root/Shoot ratio
0.33 0.22 0.24 1.01
(52%) (14%) (21%) (17%)
31
T
a
bl
e 5.
R
2
va
l
u
e
s
f
o
r
r
e
g
r
e
s
s
i
o
n
s
be
t
w
e
e
n
ba
r
e
r
o
o
t
ye
ll
o
w
p
o
p
l
a
r
s
e
e
d
l
i
n
g
m
o
r
p
ho
l
o
g
i
c
a
l
va
r
i
a
b
l
e
s
s
a
m
p
le
d
f
r
o
m
J
u
l
y
E
a
s
t
T
e
nne
s
s
e
e
N
u
r
s
e
r
y
a
t
D
e
l
a
no
,
T
N
(n
=
4
5
7
).
(
C
o
d
e)
HT
RCD N
L
NLR
L
A
NF
OB
LV
F
O
B
S
T
T
A
P
F
O
L
R
He
i
g
h
t
0
.
9
4 0.
85
0.
78
0
.
3
9
0.88
0
.
8
8
0.96
0.90
0.85
0
.
6
5
t
o
No
ve
mbe
r
a
t
t
h
e
S
T
E
M
ROO
T
T
O
T
0
.
9
2
0.83
0
.
9
1
Pr >
F
HT
?
<
.
0
1
<.01
<.01
0
.
0
2
<.01
<.
0
1
<.01
<.01
<.01
<
.
0
1
RCD
0
.
9
4
0.
88
0.
90
0
.
5
0
0.96
0
.
8
9
0.94
0.98
0.94
0
.
7
5
Pr >
F
RC
D
<.
01
?
<.01
<.01
<.0
1
<.01
<.
0
1
<.01
<.01
<.01
<
.
0
1
N
o
.
o
f
L
e
a
v
e
s
0
.
85
0.88
0.
73
0
.
3
1
0.89
0
.
7
7
0.85
0.82
0.82
0
.
5
7
Pr >
F
NL
<.
01
<.
01
?
<.01
<.0
1
<.01
<.
0
1
<.01
<.01
<.01
<
.
0
1
No
.
o
f
F
O
LR
1
0.
7
8
0
.
9
0
0.
73
0.
60
0
.
8
7
0.
82
0
.
82
0.93
0.88
0
.
8
4
Pr >
F
NLR
<.
01
<.
01
<.01
?
<.0
1
<.01
<.
0
1
<.01
<.01
<.01
<
.
0
1
L
e
a
f
A
r
ea
0.
3
9
0
.
5
0
0.
31
0.
60
0
.
4
7
0.
3
2
0.39
0.54
0.51
0
.
2
9
Pr >
F
LA
0.02
<.
0
1
<.01
<.01
?
0.01
0
.
0
5
0.02
<.01
<.01
0
.
0
7
No
.
o
f
F
OB
2
0.
8
8
0
.
9
6
0.
89
0.
87
0.
47
0.
87
0
.
9
0
0
.
9
4
0
.
9
3
0.
74
Pr >
F
NF
OB
<.
01
<.
01
<
.
0
1
<
.
0
1
0.
01
?
<.
0
1
<.01
<.01
<.01
<
.
0
1
Dr
y
Weig
h
t
(n
=
8
4
)
L
e
a
v
e
s
0.
8
8
0
.
8
9
0.
77
0.
82
0.
32
0
.
87
0.87
0.88
0.81
0
.
8
0
<
.
0
1
<.01
<
.
0
1
0
.
9
7
0.93
0
.
9
7
<
.
0
1
<.01
<
.
0
1
0
.
8
3
0.79
0
.
8
3
<
.
0
1
<.01
<
.
0
1
0
.
9
0
0.90
0
.
9
1
<
.
0
1
<.01
<
.
0
1
0
.
4
3
0.47
0
.
4
4
0
.
1
0
<.01
<.
0
1
0.
93
0
.
9
2
0.
94
<
.
0
1
<.01
<
.
0
1
0
.
9
6
0.84
0
.
9
5
Pr >
F
LV
<.
01
<
.
0
1
<
.
01
<.
01
0.
05
<
.
0
1
?
<.
01
<
.
0
1
<
.
0
1
<.
01
<.
01
<
.
0
1
<.
01
F
O
B
0.
9
6
0
.
9
4
0.
85
0.
82
0.
39
0
.
9
0
0.
87
0
.
9
3
0
.
9
1
0.
73
0.
94
0
.
9
0
0.
94
Pr >
F
FO
B
<.01
<
.
0
1
<
.
01
<.
01
0.
02
<
.
0
1
<
.
01
?
<.01
<.01
<
.
0
1
<
.
0
1
<.01
<
.
0
1
St
em
0.
9
0
0
.
9
8
0.
82
0.
93
0.
54
0
.
9
4
0.
88
0
.
9
3
0
.
9
7
0.
82
0.
97
0
.
9
7
0.
98
Pr >
F
ST
<.01
<.01
<.0
1
<
.
0
1
<.0
1
<.01
<.
0
1
<.01
?
0.01
<.
01
<.
01
<
.
0
1
<.
01
T
a
pr
oo
t
0.
8
5
0
.
9
4
0.
82
0.
88
0.
51
0
.
9
3
0.
81
0
.
9
1
0
.
9
7
0.
79
0.
92
0
.
9
8
0.
94
Pr >
F
TA
P
<.
0
1
<.01
<.0
1
<
.
0
1
<.0
1
<.01
<.
0
1
<.01
0.01
?
<.
01
<.
01
<
.
0
1
<.
01
F
O
L
R
0.
6
5
0
.
7
5
0.
57
0.
84
0.
29
0
.
7
4
0
.
8
0
0.73
0.82
0.79
0
.
8
2
0.79
0
.
8
3
Pr >
F
FO
L
R
<.
0
1
<.01
<.0
1
<
.
0
1
0
.
0
7
<.01
<.
0
1
<.01
<.01
<.01
?
<.
01
<
.
0
1
<.
01
32
TA
B
L
E
5
. C
o
nti
n
u
e
d
.
To
t
a
l
(
C
o
d
e) HT
RCD
N
L
NLR
L
A
NF
OB
LV
F
O
B
S
T
T
A
P
F
O
L
R
S
T
E
M
ROO
T
T
O
T
S
t
em
0.
9
2
0
.
9
7
0.
83
0.
90
0.
43
0
.
9
3
0
.
9
6
0.94
0.97
0.92
0
.
8
2
0.94
0
.
9
9
Pr
>
F
STEM
<.
0
1
<.01
<.0
1
<
.
0
1
0
.
1
0
<.01
<.
0
1
<.01
<.01
<.01
<
.
0
1
?
<.01
<
.
0
1
Roo
t
0.
8
3
0
.
9
3 0.
79
0.
90
0.
47
0
.
9
2 0.
84
0
.
9
0
0
.
9
7
0
.
9
8
0.
79
0.
94
0.
96
Pr
>
F
RO
OT
<.
0
1
<.01
<.0
1
<
.
0
1
<.0
1
<.01
<.
0
1
<.01
<.01
<.01
<
.
0
1
<
.
0
1
?
<.
01
Se
e
d
l
i
n
g
TO
T
0.
9
1
0
.
9
7 0.
83
0.
91
0.
44
0
.
9
4 0.
95
0.94
0.98
0.94
0
.
8
3
0
.
9
9
0.96
?
Pr
>
F
<.
0
1
<.01
<.0
1
<
.
0
1
<.0
1
<.01
<.
0
1
<.01
<.01
<.01
<
.
0
1
<
.
0
1
<.01
?
A
l
l
v
a
r
i
ab
le
s
w
e
r
e
po
s
itiv
e
l
y
co
r
r
e
l
a
te
d
1
F
i
rs
t
O
rd
e
r
L
a
t
e
ra
l
R
o
o
t
s
2
F
i
r
s
t
O
r
d
e
r
Br
a
n
ch
es
33
Green Ash
Green ash averaged 7.4 mm RCD and 40.7 cm height at the November sampling,
seven months after sowing in April. The largest increases in root collar diameter (RCD)
and leaf area occurred from July to September with 38% and 65% respectively, of
seedling growth occurring in this period. First order lateral roots (FOLR), on the other
hand, had its largest development (58%) from September to November. Interestingly, the
largest increases in first order branches (FOB), number of leaves, and shoot height
occurred from May to July with around 55% of their maximum development. FOB
actually declined 97% from September to November, yet the remaining branches
accounted for 20% of maximum FOB weight.
Fewer leaves and branches were produced after July and shoot height growth
slowed, yet there was an increase in foliar area by 100%. Sixty six percent of total leaf
dry weight was added from July to September. Stem dry weight and tap root dry weight
increased similarly during the period with 70% and 57%, respectively, of its maximum
dry weight. Interestingly, stem dry weight, tap root weight, and FOLR weight increased
significantly from September to November with FOLR dry weight increasing by nearly
300% from September to November. This increase in root mass impacted the root/shoot
ratio which increased from 0.5 to 1.3 during this period.
34
Seedling Morphological Variability
Dependent upon the morphological parameter measured, seedling variability may
have increased, decreased or remained the same over the season. Apparent patterns are
difficult to determine although the CV for average number of leaves greatly increased
from May through September while the CV first order lateral roots decreased from July
through September (Table 6).
Correlations between Seedlings Morphological Parameters
Correlations between either height or RCD and other morphological variables
were generally strong (>0.70). RCD was strongly correlated to first order lateral roots (R
2
= 0.92, prob. F<0 .01). Leaf area correlated well with only 4 out of 13 variables (Table
7). The number of first order branches showed weak correlation with all parameters
tested. Total stem and root weight correlated well with most of the variables except to the
number of first order lateral roots; however, FOLR does correlate with the total seedling
weight.
35
Table 6. Average value for morphological parameters of green ash seedlings sampled
on specific dates at the Tennessee Division of Forestry Nursery (Coefficient of
variation in parenthesis).
May July September November
N 187 195 261 190
RCD (mm)
1.2 3.6 6.4 7.4
(33%) (36%) (38%) (36%)
Shoot Height (cm)
4.2 28.2 43.1 40.7
(38%) (38%) (39%) (41%)
N
o
of Leaves
5.7 24.6 38.6 0
(23%) (50%) (96%) -
N
o
of First Order Lateral Roots
0 1.2 5.3 12.7
- (133%) (91%) (65%)
N
o
of First Order Branches
2 8.5 12.3 0.3
(80%) (79%) (63%) (233%)
Leaf Area (cm
2
)
5.9 243.9 702.9 0
(20%) (42%) (35%) -
Dry Weight (g/seedling)
Leaves
0.0257 0.68 2.01 0
(23%) (42%) (46%) -
First Order Branches
0.0005 0.05 0.3 0.06
(100%) (59%) (31%) (44%)
Stem
0.0107 0.67 4.58 5.6
(19%) (45%) (31%) (44%)
Tap Root
0.0125 0.33 2.57 3.92
(13%) (38%) (20%) (48%)
First Order Lateral Roots
0 0.06 1.01 3.53
- (75%) (32%) (52%)
Total Shoot
0.0367 1.41 6.83 5.65
(20%) (44%) (35%) (44%)
Total root
0.0125 0.39 3.58 7.45
(13%) (42%) (20%) (50%)
Total dry mass
0.049 1.79 10.41 13.1
(16%) (44%) (28%) (47%)
Root/Shoot ratio
0.35 0.27 0.55 1.29
(26%) (7%) (18%) (7%)
36
T
a
bl
e 7.
R
2
va
l
u
e
s
f
o
r
r
e
g
r
e
s
s
i
o
n
s
be
t
w
e
e
n
ba
r
e
r
o
o
t
g
r
e
e
n A
s
h s
e
e
d
l
i
n
g
m
o
r
p
h
o
l
o
g
i
c
a
l
va
r
i
a
b
le
s
s
a
m
p
l
e
d
f
r
o
m
J
u
l
y
t
o
N
E
a
s
t
T
e
nne
s
s
e
e
N
u
r
s
e
r
y
a
t
D
e
l
a
no
,
T
N
(n
=
6
4
6
).
(
C
o
d
e)
HT
RCD
NL
NL
R
L
A
NF
OB
L
V
F
OB
S
T
T
A
P
F
OL
R
ST
E
M
H
e
i
g
h
t
0.88
0.83
0
.
8
4
0
.
7
2
0
.
4
5
0.68
0
.
7
9
0.75
0.87
0.70
0.76
o
ve
mbe
r
a
t
t
he
ROOT
T
OT
0
.
8
3
0
.
8
1
Pr >
F
HT
?
<
.
0
1
<.
01
<.
01
<
.
0
1
0.
02
<
.
0
1
<.
01
<
.
0
1
<
.
0
1
<
.
0
1
<
.
01
R
C
D
0.
88
0
.
6
9
0.
92
0.
73
0.
42
0
.
5
3
0.
77
0
.
7
6 0
.
9
0
0
.
8
2
0
.
7
1
Pr >
F
RC
D
<.01
?
<.
01
<.
01
<.01
0.
02
0
.
0
1
<.
01
<
.
0
1
<
.
0
1
<
.
0
1
<
.
01
No
.
o
f
Lea
v
e
s
0.
83
0
.
6
9
0.
77
0.
65
0.
50
0
.
8
3
0.
85
0
.
8
1 0
.
8
0
0
.
6
9
0
.
8
4
Pr >
F
NL
<.01
<.
01
?
<.
01
<
.
0
1
0.
01
<
.
0
1
<.
01
<
.
0
1
<
.
0
1
<
.
0
1
<
.
01
No
.
o
f
F
O
LR
1
0.
84
0
.
9
2
0
.
7
7
0.
67
0.
32
0
.
5
8
0.
8
4
0.82
0.98
0.92
0.78
Pr >
F
NL
R
<.01
<.
01
<.
01
?
<.01
0
.
0
6
<.01 <
.
0
1
<.01
<.01
<.01
<.0
1
L
e
a
f
A
r
ea
0.
72
0
.
7
3
0
.
6
5
0.
67
0.
27
0
.
60 0
.
6
1
0.67
0.73
0.51
0.67
Pr >
F
LA
<.01
<.01
<
.
0
1
<
.
0
1
?
0.
19
<
.
0
1
<.
01
<
.
0
1
<
.
0
1
<
.
0
1
<
.
01
No
.
o
f
F
OB
2
0.
45
0
.
4
2 0
.
5
0
0.
32
0.
27
0
.
2
9
0.
3
3
0.24
0.28
0.24
0.27
Pr >
F
NF
O
B
0.
02
0
.
0
2 0
.
0
1
0.
06
0.
19
?
0.08 0
.
6
3
0.11
0.09
0.12
0.09
Dr
y
Weig
h
t
(n
=
8
4
)
L
e
a
v
e
s
0.
68
0
.
5
3 0
.
8
3
0.
58
0.
60
0.
29
0
.
8
6
0.84
0.67
0.55
0.91
<.
01
<.
01
0.
90
0.
80
<.
01
<.
01
0.
78
0.
85
<.
01
<.
01
0
.
9
8
0
.
8
7
<
.
0
1
<
.
0
1
0
.
6
7
0
.
7
0
<.
01
<.
01
0
.
2
7
0
.
2
8
0
.
0
9
0
.
0
9
0
.
6
5
0
.
8
5
Pr >
F
LV
<.
01
0
.
0
1
<.
01
<.
01
<
.
0
1
0.
08
?
<
.
0
1
<.01
<.01
<.01
<.0
1
FO
B
<
.
0
1
<
.
0
1
F
O
B
0.
79
0
.
7
7 0
.
8
5
0.
84
0.
61
0.
33
0.86 0.93
0.89
0.83
0.94
0
.
8
9
0
.
9
6
Pr >
F
<.
01
<
.
0
1
<.
01
<.
01
<
.
0
1
0.
63
<
.
0
1
?
<.01
<.01
<.01
<.0
1
<
.
0
1
<
.
0
1
St
em
0.
75
0
.
7
6 0
.
8
1
0.
82
0.
67
0.
24
0
.
8
4
0.
93
0
.
8
8
0
.
8
7
0
.
9
8
0.
90
0.
98
Pr >
F
ST
<.
01
<
.
0
1
<.
01
<.
01
<
.
0
1
0.
11
<
.
0
1
<.
01
?
<.01
<.01
<.0
1
<
.
0
1
<
.
0
1
T
a
pr
oo
t
0.
87
0
.
9
0 0
.
8
0
0.
98
0.
73
0.
28
0
.
6
7
0.
89
0
.
8
8
0
.
9
0
0
.
8
5
0.
99
0.
93
Pr >
F
TA
P
<.01
<
.
0
1
<.
01
<.
01
<
.
0
1
0.
09
<
.
0
1
<.
01
<
.
0
1
?
<
.
0
1
<
.
01
<.
01
<.
01
F
O
L
R
0.
70
0
.
8
2 0
.
6
9
0.
92
0.
51
0.
24
0
.
5
5
0.
83
0
.
8
7 0
.
9
0
0
.
8
0
0.
95
0.
88
Pr >
F
FO
L
R
<.01
<.01
<
.
0
1
<
.
0
1
<.01
0
.
1
2
<.01 <.
0
1
<.01
<.01
?
<
.
01
<.
01
<.
01
37
TA
B
L
E
7
. C
o
nti
n
u
e
d
.
To
t
a
l
(
C
o
d
e) HT
RCD
N
L
NLR
L
A
NF
OB
LV
F
O
B
S
T
T
A
P
F
O
L
R
S
T
E
M
ROO
T
T
O
T
S
t
em
0.
7
6
0
.
7
1
0.
84
0.
78
0.
67
0
.
2
7
0
.
9
1
0.94
0.98
0.85
0
.
8
0
0.85
0
.
9
8
Pr
>
F
STEM
<.
0
1
<.01
<.0
1
<
.
0
1
<.0
1
0.09
<.
0
1
<.01
<.01
<.01
<
.
0
1
?
<.01
<
.
0
1
Roo
t
0.
8
3
0
.
9
0 0.
78
0.
98
0.
67
0
.
2
7 0.
65
0
.
8
9
0
.
9
0
0
.
9
9
0.
95
0.
85
0.
93
Pr
>
F
RO
OT
<.
0
1
<.01
<.0
1
<
.
0
1
<.0
1
0.09
<.
0
1
<.01
<.01
<.01
<
.
0
1
<
.
0
1
?
<.
01
Se
e
d
l
i
n
g
TO
T
0.
8
1
0
.
8
0 0.
85
0.
87
0.
70
0
.
2
8 0.
8
5
0.96
0.98
0.93
0
.
8
8
0
.
9
8
0.93
Pr
>
F
<.
0
1
<.01
<.0
1
<
.
0
1
<.0
1
0.09
<.
0
1
<.01
<.01
<.01
<
.
0
1
<
.
0
1
<.01
?
?
A
l
l
v
a
r
i
ab
le
s
w
e
r
e
po
s
itiv
e
l
y
co
r
r
e
l
a
te
d
1
F
i
rs
t
O
rd
e
r
L
a
t
e
ra
l
R
o
o
t
s
2
F
i
r
s
t
O
r
d
e
r
Br
a
n
ch
es
38
DISCUSSION
Seedling Size
A minimum RCD of 9.5 mm and 45 cm height for hardwood seedlings is
recommended by the Alabama Forestry Commission (AFC, 1997). Wann and Rakestraw
(1998) recommended a minimum of 10 mm RCD for hardwood planting stock. Of the
three species produced in this study, only yellow poplar can be said to meet this criteria.
Green ash was the smallest species observed with an average height of only 42 cm. This
is difficult to explain as site, fertilization, and sowing times are comparable with the other
two species, and others (Kennedy, 1990) have found green ash capable of growing 0.8 ?
1.0 m in height during the nursery season. The influence of seed source cannot be
discounted in this case. Typical of most hardwood sources, this seed was part of a mixed
lot and the exact origin is unknown. Shorter green ash height may be advantageous for
nursery managers as the species is not top pruned as it typically results in severe forking
(South, 1996). Although pruning has not been performed during the season, all species
had root/shoot weight ratio <1.4, which is considered well balanced (Miller, 1996).
Yellow poplar was the tallest species and was much taller than a typically
marketable seedling. The seedlings were 20% taller than yellow poplar seedling grown
under standard nursery cultural practices at the Indiana Department of Natural Resources
(Jacobs et al., 2005). With an average height of 92 cm, yellow poplar was more than
twice as tall as green ash and 60% taller than Nuttall oak. With 57 cm of height Nuttall
oak was 40% taller than the average Nuttall oak seedlings commonly planted in the lower
Mississippi Alluvial Valley (Schweitzer et al., 1997). Yellow poplar was consistently the
39
largest species but did not have the highest November root/shoot ratio which was highest
for green ash, followed by yellow poplar and Nuttall oak. Even tough Nuttall oak
seedlings were generally larger than green ash seedlings, and the latter had more than
twice as much mass in first order lateral roots. First order lateral roots were only 12% of
the total root mass of Nuttall oak at the November sample date, yet 47% of the root mass
of green ash and 57% of the root mass of yellow poplar. It appears that Nuttall oak may
tend to put root development primarily into the taproot.
Another factor that can greatly impact seedling development is bed spacing. The
average bed spacing for Nuttall oak, yellow poplar, and green ash was 52.1, 43.5, and
56.2 per m
2
of bed surface. While the largest species also had the widest spacing (yellow
poplar), there was still a very large difference in seedling size between Nuttall oak and
green ash, and only a small change in spacing. Obviously the difference in size between
species cannot be safely attributed to bed spacing.
Growth Periodicity
The three species demonstrated distinct and unique periodicity of major plant
organ development over the nursery season. In terms of aboveground development,
yellow poplar increased height 61% from July to September while the larger share of
height growth for green ash occurred from May to July (Table 8). Little, if any,
aboveground growth of these two species occurred in September to November, yet the
aboveground component of Nuttall oak increased by 18% during this period. Nuttall oak
was the last to drop its leaves in the fall. There was significant root growth of Nuttall oak
from September through November when this species produced 56% of its final root
40
mass. Harris et al. (1995) observed a similar pattern with root growth beginning after
shoot growth in green ash and in some oak species. Green ash and yellow poplar also
increased root mass by large amounts during the fall period. The development of first
order lateral roots in yellow poplar and green ash from September to November was
substantial. FOLR increased by 140% in number and 381% in mass in the case of yellow
poplar. An increase of 139% in number and 249% in mass of green ash occurred during
the same two month period. It is not known how much root mass increased before leaf
fall as opposed to after.
Table 8. Growth of RCD, height, and root mass for yellow poplar, Nuttall oak, and green
ash during three periods of the nursery growing season expressed as of percentage of the
November sample value
May? July July?
Septmeber
September?
November
RCD ? ? ? ? ? ? ? ? ? ? % ? ? ? ? ? ? ? ? ? ? ? ?
N. oak 21 14 36
Y. poplar 25 41 25
G. ash 32 38 14
Height
N. oak 25 41 18
Y. poplar 34 61 3
G. ash 59 37 0
Root
N. oak 9 32 56
Y. poplar 3 49 48
G. ash 5 43 52
Intra-Specific variability
It is generally accepted that hardwood seedlings are highly variable in terms of
morphological development (Wilson and Jacobs, 2004). All three species in this study
41
showed this characteristic with high coefficients of variation in the November sample for
virtually all morphological parameters measured. The CVs for November RCD, for
example, ranged from 36% to 40% and those for height ranged from 32% to 44%.
Comparatively, smaller variation has been observed in four southern nurseries for
loblolly pine with average CVs ranging from 17% to 22% for RCD and from 7% to 21%
for heights (unpublished data, 2006). In a study with english oak (Quercus robur L.) and
white oak (Quercus alba L.), Clausen (1983) reported seedlings graded as medium with
slightly higher CVs of 49% and 46%, respectively. The variability of first order lateral
roots and branches was very high, ranging from 52% to 86% for the former, and 75% to
233% for the latter. One cause for this variability may be spacing irregularities since
target densities are rarely attained uniformly across a nursery, resulting in a large
variation in seedling size (Jacobs, 2003). Average spacing for Nuttall oak, for example,
varied from 101 seedlings/m
2
in the September sample to 73 seedlings/m
2
for the July
samples. These averages were comparable with typical growing densities on different
species of hardwood seedlings in the Central Hardwood Region ranging from 43 to 129
seedlings/m
2
(Jacobs, 2003). Sowing irregularities, variable germination, or even mulch
depth might influence seedling size variability. Particular attention to sowing and mulch
techniques may improve germination uniformity. Karrfalt (2005) found that small
differences in acorn size can result in substantial seedling size differences. Seedling
variability is important from a practical standpoint, as uniformity can attract and retain
customers, especially if there is a regional seedling surplus (South, 1998). Seedling
morphological variability is still visible in the field many years after planting (Jaenicke,
1999).
42
Correlations of Morphological Parameters
There were a large number of strong correlations between morphological
parameters for all three hardwood species of this study. Of particular importance are the
strong correlations between RCD and other parameters. The number of first order lateral
roots has been linked to outplanting performance by Kormanik (1986) and Schultz and
Thompson (1997). The three species studied here have strong correlations between RCD
and the number of first order lateral roots and to a slightly lesser extent their mass. These
data indicate that RCD may be used as a surrogate for first order lateral roots as an
indicator of seedling quality. Similar RCD correlations were reported for sweetgum by
McNabb (2001) with accurate prediction for both the number and biomass of first order
lateral roots as well as for other several parameters with R
2
above 0.90. In the current
study, height also had reasonably good correlations with the number of first order
laterals, but not as strong as with RCD.
Implications for seedling production
Hardwood seedling culture may involve a number of different cultural practices,
including weed control, fertilization, top pruning, and mechanical lifting. It seems
apparent there are distinct characteristics of morphological development of yellow
poplar, Nuttall oak and green ash. Whether there might be an interaction between
morphological development and the timing and nature of cultural treatments is difficult to
interpret. It is possible, for example, that earlier and larger applications of nitrogen
fertilizer may have changed the timing of seedling morphological development. In the
case of green ash, most of the foliar expansion occurred from May to July. Latter
43
applications of nitrogen may not have been as effective in promoting growth as would
have been earlier applications in May and June.
It?s apparent that all three species showed considerable intra-specific variability in
morphological development. Because uniformity is a desired seedling crop characteristic,
development of strategies to increase uniformity should be a high priority to hardwood
nursery managers. The relatively high variability in seedling spacing undoubtedly
contributes to morphological variability. A high priority should be given to the
development of management techniques that improve uniform germination. These might
include improved seed quality, better matching of seed source to nursery location, more
uniform stratification techniques, more uniform sowing and mulching depth, and better
sowing equipment. Shoot pruning can be used to improve uniformity and facilitate
handling (Sterling and Lane, 1975).
.
44
CONCLUSION
Yellow poplar, Nuttall oak, and green ash produce seedlings of different size even
when grown under similar soil fertility and climatic conditions. Yellow poplar grew the
fastest over the nursery season, followed by Nuttall oak, and green ash. The size
difference between species was substantial with yellow poplar having 46% more total
seedling dry mass in November than did Nuttall oak and 208% more than Green ash.
There were distinct periodicities to the morphological development of each
species. Yellow poplar increased aboveground dry weight most significantly in the July
to September period, whereas green ash added more dry weight in May through July
period. Nuttall oak continued to add aboveground dry weight through the September to
November period, increasing aboveground dry weight by 30%. All three species showed
considerable root dry weight gains from September to November.
All three species showed extensive intra-specific variability in seedling
morphology with high coefficients of variation for virtually all parameters. Because
environmental conditions, soil type, and cultural treatments were similar between all
three species, this high degree of variability is probably due to factors related to seed
vigor, seed source, and other as yet undefined factors.
All three species showed strong correlations between numbers of seedling
morphological parameters. Both height and RCD correlated well with several parameters
including first order lateral roots. The strength of these correlations indicated that both,
particularly RCD, might be used as an accurate determinant of overall morphological
development, and therefore seedling quality.
45
REFERENCES
Barnett, J.P. 2002. Trends in nursery research and production. In: Dumroese, R.K., Riley,
L.E., and Landis, T.D., tech. coord.. National Proceedings: Forest and
Conservation Nursery Associations-1999, 2000, and 2001.Proceedings RMRS-P-
24. Ogden, UT: USDA Forest Service, Rocky Mountain Research Station: 97-
100.
Clausen, K.E. 1983. English oak grows better than white oak of comparable seedling
size. Tree Planter?s Note. 34(4): 17-19.
Dey, D.C. and Parker, W.C. 1997. Morphological indicators of stock quality and field
performance of red oak (Quercus rubra L.) seedlings underplanted in a central
Ontario shelterwood.New Forests 14(2): 145-156.
Gardiner, E.S., Russell, D.R., Oliver, M., and Dorris, L.C. 2002. Bottomland hardwood
afforestation: state of the art. In: Holland MM, Warren ML, Stanturf JA, editors.
Proceedings of a conference on sustainability of wetlands and water resources:
how well can riverine wetlands continue to support society into the 21st century?
Asheville (NC): USDA Forest Service, Southern Research Station. General
Technical Report SRS-50. p 75-86.
Harris, J.R., Bassuk, N. L., Zobel, R. W., and Whitlow, T. H. 1995. Root and shoot
growth periodicity of green ash, scarlet oak, Turkish hazelnut, and tree lilac.
Journal of American Society of Horticultural Science 120: 211-216
Jacobs, D.F. 2003.Nursery production of hardwood seedlings. Purdue University
Cooperative Extension Service, FNR-212, 8 pp.
Jacobs, D.F. and Seifert, J.R. 2004. Re-evaluating the significance of the first-order
lateral root grading criterion for hardwood seedlings. In: Proceedings of the
Fourteenth Central Hardwood Forest Conference. Wooster, OH, 16-19 March
2004. USDA For. Serv. North Central Exp. Sta. Gen. Tech. Rep. NE-316, pp.
382-388.
Jacobs, D.F, Salifu, K.F., and Seifert, J.R. 2005. Growth and nutritional response of
hardwood seedlings to controlled-release fertilization at outplanting.Forest
Ecology and Management. 214:28-31
Jaenicke, H. 1999. Good tree nursery practices. International centre for research in
agroforestry. Research nurseries. ICRAF, Nairobi, Kenya. 83 pp. [Online WWW].
Available URL:
?http://www.worldagroforestry.org/NurseryManuals/Research/Title.pdf?
[Accessed 18 September 2005].
46
Karrfalt, R.P. 2005. Acorn size effects seedling size at the Penn Nursery. In: Dumroese,
R. K., Riley, L. E.,and Landis, T. D., tech. coords. 2005. National proceedings:
Forest and Conservation Nursery Associations?2004; 2004 July; Charleston, NC
and Medford, OR. Proc. RMRS-P-35. Fort Collins, CO: U.S. Department of
Agriculture, Forest Service, Rocky Mountain Research Station. p. 65-68.
Kennedy, H.E. 1990. In: Burns, R. M. and Honkala, B. H., tech. coords. 1990. Silvics of
North America: 1. Conifers; 2. Hardwoods. Agriculture Handbook 654. U.S.
Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 p.
Kormanik, P.P. 1986. Lateral root morphology as an expression of sweetgum seedling
quality. Forest Science. 32:595-604.
Lockhart, B.R., Keeland, B., McCoy J., and Dean T.J. 2003. Comparing regeneration
techniques for afforesting previously farmed bottomland hardwood sites in the
Lower Mississippi Alluvial Valley, USA. Forestry 76: 169-180.
Matherne, C. 2002. Propagating hardwood seedlings in Louisiana. In: National
proceedings: forest and conservation nursery associations - 1999, 2000, and 2001.
Dumroese, R.K., Riley, L.E., and Landis, T.D., tech. coords. USDA Forest
Service, Rocky Mountain Research Station, Proceedings RMRS-P-24, p.234-235.
McNabb, K., 2001. The morphology of sweetgum seedlings. Auburn University Southern
Forest Nursery Management Cooperative. Research Report 01-12. Auburn
University. Auburn, AL.
McNabb, K. and Santos, H.Z. 2004. A survey of forest tree seedling production in the
south for the 2003-2004 planting season. Southern Forest Nursery Management
Cooperative, Technical Note 04-02. Auburn University. Auburn, AL.
Miller, S. 1996. Successful tree planting techniques for drastically disturbed lands: a case
study of the propagation and planting of container-grown oak and nut trees in
missouri. Presented at the 18
th
annual Meeting of Association of the Abandoned
Mine Land Programs, Kalispell, Montana, 1996. United States Fish and Wildlife
Service, 1997. Region 3 Endangered Species Home Page. Fort Snelling,
Minnesota.
Schultz, R.C. and Thompson, J.R. 1997. Effect of density control and undercutting on
root morphology of 1+0 bareroot hardwood seedlings: five-year field performance
of root-graded stock in the central USA, New Forests 13: 301- 314
47
Schweitzer, C.J., Stanturf, J.A., Shepard, J.P., Wilkins, T.M., Portwood, C.J., and Dorris,
L.C. 1997. Large-scale Comparison of Reforestation Techniques Commonly Used
in the Lower Mississippi Alluvial Valley: First Year Results. Department Of
Agriculture. Forest Service. General Technical Report NC. 188: 313-320
Smith, D.M. 1999 Hardwood seedlings as an alternative crop for small farms.
Agricultural Marketing Outreach Workshop Training Manual. USDA. Memphis,
TN. April 11-13, 2000. [Online WWW]. Available URL:
?http://marketingoutreach.usda.gov/info/99Manual/hardwood.htm? [Accessed 11
July 2006].
South, D.B. 1996. Top-Pruning bareroot hardwoods: A review of the literature. Tree
Planters Notes 47(1):34-40.
South, D.B. 1998. Effects of top-pruning on survival of southern pines and hardwoods. In
Proc., 9th Biennial S. Silv. Res. Conf. USDA For. Serv. Gen. Tech. Rep. SRS-20.
pp. 3-8.
South, D.B. and Carey, A.W. 2005. Weed control in bareroot hardwood nurseries. pp. 34-
38. In: Dumroese, R. K., Riley, L. E., and Landis, T. D., tech. coords. 2005.
National proceedings: Forest and Conservation Nursery Associations?2004;
2004 July; Charleston, NC and 2004 Medford, OR. Proc. RMRS-P-35. Fort
Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain
Research Station. 142 p.
Sterling, K.A. and Lane, C.L. 1975. Growth and development of shoot and root pruned
yellow-poplar seedings on two sites. Tree Planters? Notes 26(3): 1-2, 25.
Thompson J.R. and Schultz R.C. 1995. Root system morphology of Quercus rubra L.
planting stock and 3-year field performance in Iowa. New For. 9: 225-236.
Wann, S. R. and Rakestraw, J. L. 1998. Maximizing hardwood plantation productivity in
the Southeastern United States -Lessons learned from loblolly pine. In:
Conference Proceedings. A Key to Sustainability, Duluth, Minnesota.
Ward, J.S., Gent, M.P.N., and Stephens, G.R. 2000. Effects of planting stock quality and
browse protection-type on height growth of northern red oak and eastern white
pine. Forest Ecology and Management 127: 205-216.
Wightman, K.E. 1999. Good tree nursery practices. Practical guidelines for community
nurseries. International Centre for Research in Agroforestry. 95 pp.
Wilson, B.C. and Jacobs, D.F. 2004.Quality assessment of hardwood seedlings.
Hardwood tree improvement and regeneration Center. Poster. Purdue University
Department of Forestry and Natural Resources. West Lafayette, Indiana.
48
III. NUTRITIONAL DEVELOPMENT OF THREE SPECIES OF NURSERY-
GROWN HARDWOOD SEEDLINGS IN TENNESSEE
ABSTRACT
The nutritional development of three hardwood species grown under southern
hardwood nursery cultural practices were compared and their seasonal periodicity of
nutrient concentrations, translocation, and allocation were documented. Yellow poplar
(Liriodendron tulipifera L), Nuttall oak (Quercus nuttallii Palmer), and green ash
(Fraxinus pennsylvanica Marsh) production resulted in small shifts in soil nutrient levels
from May to November. However, there were no changes in soil carbon and organic
matter content, probably as a result of the addition of mulch and leaf litterfall. In spite of
similar fertilization regimes, foliar nutrient concentrations varied by species (when
averaged across the growing season). Yellow poplar appeared to be the most efficient at
withdrawing nutrients from senescent leaves while Nuttall oak had higher nutrient
translocation efficiencies. Significant amounts of fertilizer elements were removed by
harvesting, but overall removal of nitrogen and phosphorous was lower than the total
fertilizer application. Nitrogen use efficiency was relatively high for all species. Yellow
poplar had highest nitrogen removal efficiency and biomass productivity, followed by
Nuttall oak and green ash.
49
INTRODUCTION
The demand for hardwood planting stock has held steady over the past several
years and may have increased (Barnett, 2002) due to federal cost share programs
including wetland restoration programs (Smith, 1999; Matherne, 2002). Hardwood
seedlings are 3.6% of the total southern nursery production and are grown in less than
half of all southern tree nurseries (McNabb and Santos, 2004). Nevertheless, the
hardwood crop is an important source of nursery revenue since on an area basis it is more
valuable than a pine crop (South and Carey, 2004).
Most nursery research has focused on issues related to conifers due to their larger
production numbers. As a result there is relatively little literature for hardwood seedling
culture (Wilson and Jacobs, 2004). Very little is known about the nutrient requirements
of relatively important hardwood species. Information on optimum nutrient levels, critical
ranges for essential elements, and physiological effects of nutrient deficiencies is limited
(Erdmann et al., 1979). Conifers have less than half the annual nutrient requirement of
most hardwoods (Lassoie et al., 1985). Pines retain numerous age classes of foliage and
thus have lower demand for foliage replacement (Elliot and White, 1993). Nutrient
requirements are generally higher for hardwood seedlings, especially nitrogen (N), with
hardwood seedlings requiring 50% more N than pines (Davey, 1994) as well as higher
amounts of phosphorus (P), calcium (Ca), and magnesium (Mg). Available literature
about hardwood micronutrient nutrition (Stone, 1968) is more limited than for
macronutrients (Davey, 1994).
50
Fertilization recommendations are based on soil analysis (Triebwasser, 2003).
Most hardwood nursery standards were set nearly 30 years ago with little input from
hardwood fertility research (McNabb, 2004). The main concern of nursery managers is
with nitrogen (Dumroese, 2003). It is the most commonly deficient nutrient, especially
when high carbon-nitrogen ratio mulch is applied on the seedbed (Williams and Hanks,
1976). Fertility standards described by Davey (1973) as cited by Stone (1980)
recommend available phosphorous at 56-168 kg/ha, potassium at 168-336 kg/ha, calcium
at 672-1,344 kg/ha, and organic matter greater than 10 g/kg. Nitrogen fertilizer top
dressings are usually applied every two weeks beginning in late spring and extending
through the summer; a typical operational nitrogen application for hardwoods is reported
to be around 204 kg/ha (McNabb, 2004).
Fertilizer prescriptions are unique to each nursery, and to continually grow high
quality seedlings on a nursery site, nutrients must be added to replace those that are lost
when seedlings are harvested (South and Boyer, 1985). Nutrient content can be
determined for a whole seedling or even particular seedling parts although foliar N
concentration is the most commonly used value for nursery stock (Dumroese, 2003). The
elements that limit productivity (for a given species on a given site) must be correctly
diagnosed before maximum growth responses to fertilization can be obtained (Brown,
1999). The quantities and application timing of nutrients required for maximum growth
may differ among hardwood species.
The objective of this research was to describe the nutritional development of three
commonly produced hardwood species under nursery conditions. This study was
conducted at the Tennessee Division of Forestry (TDF), East Tennessee Nursery in
51
Delano, Tennessee. The TDF produces approximately ten million seedlings annually,
with hardwood production close to two million seedlings. Currently, 28 hardwood
species are grown at this nursery with yellow poplar, green ash, and various oaks
produced in the largest numbers. Winter-sown Nuttall oak (Quercus nuttallii Palmer),
spring-sown green ash (Fraxinus pennsylvanica Marsh), and yellow poplar (Liriodendron
tulipifera L.) were selected for this study as they are routinely grown by the TDF and are
commonly produced in southern hardwood nurseries (McNabb & Santos, 2004).
These results should help determine seedling development parameters for the
three species and may be useful in the determination of grade criterion based on nutrient
content. Two hypotheses will be tested:
1: Hardwood seedling species from different botanical families, grown with
similar nursery practices do not affect nutrient concentrations in the soil.
2: Nutrient cycling through litterfall does not vary by month.
52
MATERIALS AND METHODS
Nursery location and Culture
This study was conducted at the Tennessee Division of Forestry (TDF), East
Tennessee Nursery in Delano, Tennessee. Soil in the study area was a sandy loam of the
Toccoa series. They are typic udifluvent soils, commonly fine-textured with stratified
layers of mineral and organic matter throughout (USDA, 1996).
A mixed lot of Nuttall oak (Quercus nuttallii Palmer) (209 seeds/kg, 100%
germination, 60% expected seed efficiency) was sown on March 1
st
using a NB-2 sower
and a 107 seeds/m
2
sowing density. A total of 3,316 linear bed meters was sown. A
mixed lot of yellow poplar (Liriodendron tulipifera L.) (43% germination, 100% purity,
80% expected seed efficiency) was sown on April 18
th
using a NB-2 sower at a target
spacing of 247 seeds/m
2
. Seeds were stratified for 90 days prior to sowing. A total of
3,332 linear bed meters were sown. A mixed lot of green ash (Fraxinus pennsylvanica
Marsh) (76% germination, 100% purity, 60% expected feed efficiency) was sown on
April 18
th
using a NB-2 sower at a target density of 141 seeds/m
2
. Seeds were stratified
for 90 days prior to sowing. A total of 2,182 linear bed meters was sown.
53
Cultural practices
A total of 287 kg/ha elemental nitrogen (N) was applied as top dressing for
Nuttall oak between May 6 and September 23 in eight applications (Table 9). Elemental
phosphorus was applied at 50 kg/ha in two applications. A directed spray of 2 ml/L
glyphosate was applied on May 11 to control weeds. Oxyfluorfen (Goal 4F
?
) was applied
at 280 grams/ha on July 29. The insecticide diazinon was applied at 2.3 kg/ha as a
directed spray on August 19.
A total of 234 kg/ha elemental N was applied as top dressing for yellow poplar
between May 6 and August 4 in seven applications (Table 9). Elemental phosphorus was
applied at 87 kg/ha in three applications. A directed spray of 20 ml/L glyphosate was
applied on May 5 and June 28 to control weeds. The selective herbicide napropamide
(Devrinol
?
) was applied at 2.25 kg/ha as a directed spray on August 16.
A total of 217 kg/ha elemental N was applied as top dressing to green ash
between May 6 and August 4 in six applications (Table 9). Elemental phosphorus was
applied at 25 kg/ha in a single application. A directed spray of 20 ml/L glyphosate was
applied on May 11 and June 29 to control weeds. The herbicide sethoxydim (Poast
?
) was
applied at 413 grams/ha on May 25.The insecticide diazinon was applied at 2.3 kg/ha as a
directed spray on August 19.
54
Table 9. Elemental fertilizer application for three hardwood species grown at the
Tennessee Division of Forestry, East Tennessee Nursery.
Species Date N kg/ha P kg/ha Product
Nuttall oak May6
39 -
Ammonium nitrate
June 2
39 -
Ammonium nitrate
June 21
22 25
Diammonium phosphate
July 20
39 -
Ammonium nitrate
July 29
39 -
Ammonium nitrate
August 4
22 25
Diammonium phosphate
August
39 -
Ammonium nitrate
September 23
48 -
Ammonium nitrate
Total
287 50
Yellow poplar May 6
39 -
Ammonium nitrate
June 2
39 -
Ammonium nitrate
June 21
22 25
Diammonium phosphate
July 20
34 37
Ammonium nitrate
July 29
39 -
Ammonium nitrate
August 4
22 25
Diammonium phosphate
August
39 -
Ammonium nitrate
Total
234 87
Green ash May 6
39 -
Ammonium nitrate
June 2
39 -
Ammonium nitrate
June 21
22 25
Diammonium phosphate
July 20
39 -
Ammonium nitrate
July 29
39 -
Ammonium nitrate
August 4
39 -
Ammonium nitrate
Total
217 25
After sowing in April, yellow poplar and green ash beds were covered with
hardwood planer mill waste (Table 10). No mulch was added to beds used to grow
Nuttall oak.
55
Table 10. Nutrient levels applied through a mulch application to
green ash and yellow poplar nursery beds
Species
Green ash Yellow poplar
Element
- - - - - - - - - - - - - - -kg/ha- - - - - - - - - --- - -
N 22.42 16.90
P 1.30 1.30
K 4.87 5.85
Ca 16.57 15.60
Mg 4.87 6.50
Al 27.46 42.60
B 0.07 0.08
Cu 0.17 0.16
Fe 17.91 29.76
Mn 1.16 1.68
Na 1.55 1.19
Zn 0.09 0.10
C 3,715.37 3,596.44
Sampling Design
All three species were sampled from 6 blocks in three separate beds. Each block
is one bed wide and 4.87 m long, for a total length of 29.2 m. Seedlings were sampled
within blocks in the months of May, July, September, and November using a 0.3 m x
1.22 m counting frame. Sample plots were randomly distributed within the block, with
0.91 m buffers between them. To carefully harvest as much of the root system as
possible, seedlings were sampled using a shovel except during the last sampling
procedure when a tractor drawn undercutting blade lowered to 33 cm deep lifted the
seedlings and then loosened the soil from around the roots. Litterfall was collected in 0.1
m
2
traps (20 cm x 50 cm) placed in each sample plot two months prior to sampling in
July, September, and November. To determine the amount of nutrients being added to the
site through mulching, sample plots of 17 cm x 16 cm were randomly established within
56
each block in May. All seedlings and mulch material were taken to laboratory facilities in
Auburn for analysis.
Soil analysis
Composite soil samples were taken to a depth of 25 cm from each block for
each species in May, prior to N fertilization and in subsequent sampling times in July,
September and November. Soil samples were analyzed by the AU Soil Testing and Plant
Analysis Laboratory. Routine elemental analyses were applied to determine phosphorus,
potassium, calcium, and magnesium using the Mehlich I solution. Phenoldisulfonic acid
method was used to determine nitrates. Micro-nutrients were determined with Inductively
Coupled Plasma (ICP) Emission Spectroscopy and organic matter determined by dry
combustion method with a LECO carbon analyzer.
Measurements
Seedling height, root collar diameter (RCD), number of first order branches
(FOB), number of first order lateral roots (FOLR) (>1mm) and number of leaves were
tallied. Fresh and dry weights were obtained for stem, taproot, FOLR, FOB, and leaves
on a plot basis. The root/shoot ratio was based on root and shoot dry weights.
Dried samples of at least 5 grams were sent to the Auburn diagnostics laboratory
for grinding and nutrient analysis. Total nitrogen and carbon were determined by
combustion. The P, K, Ca, Mg, Mn, Fe, Al, B, Cu, and Zn were determined by ICP.
Samples were taken for taproot, FOLR, FOB, and leaves by first combining each into a
57
single block and then randomly selecting sufficient material for analysis. Stem tissue
sections were taken from the lower, middle, and upper part of the stem and used for the
block combination and random selection. Litterfall collections from traps were bagged,
weighed (dry) and analyzed for nutrient content. The total number of seedling tissue
samples to be chemically analyzed was 165. Blocks 1 and 2, 3 and 4, and 5 and 6 were
combined for all nutrients? analysis.
Analysis
Total plot (block) dry weight was divided by the number of seedlings in the plot
to obtain an average seedling value for each component (at each sampling time). Nutrient
concentration and content were reported over time by species for the various seedling
morphological components. The following seedling nutrient utilization factors were
calculated:
1) Nitrogen removal efficiency (Bruulsema, 2005).
The crop nitrogen removal efficiency (NRE) was calculated at the November
sample date for (belowground, aboveground, and litterfall) seedling components of each
species.
Nitrogen harvested (kg.ha
-1
)
Nitrogen Removal Efficiency (%) =
Nitrogen applied(kg.ha
-1
)
x 100
2) Partial Factor of Productivity (Cassman et al., 2002).
Partial Factor of Productivity (PFP), the ratio of crop biomass per unit of applied
N fertilizer, was calculated for each species for (belowground, aboveground, litterfall)
seedling components at the November sample.
Biomass produced (kg.ha
-1
)
Partial Factor of Productivity =
Nitrogen applied (kg.ha
-1
)
3) Nutrient translocation efficiency (Ntanos and Koutroubas, 2002).
Nutrient translocation efficiency for N and P was calculated using foliage nutrient
content at the July sample date against nutrient content in litterfall sampled at November.
58
nutrient foliage (g.m
-2
)-nutrient litterfall (g.m
-2
)
x100Translocation efficiency =
nutrient foliage (g.m
-2
)
4) Resorption efficiency (Van Heerwarden et al., 2003).
This parameter describes the relative amount of nutrient pool translocated back
into the seedling before leaf abscission. It was calculated for each species using the
foliage in September and litterfall sampled from September to November for N and P as
denoted:
( )
Litterfall Nutrient concentration (g.g
-1
)
x100 Resorption efficiency= 1 ?
Foliage Nutrient concentration (g.g
-1
)
59
5) Nutrient use efficiency (U.S. EPA, 2002).
Seedling nutrient use efficiency (NUE) of each species was estimated for
(belowground, aboveground, litterfall) seedling components using 8 to 9 month old
seedlings to estimate the efficiency of biomass production per unit of absorbed nitrogen.
Net Primary Productivity (g.m
-2
)
NUE=
Total Nitrogen Uptake (g.m
-2
)
For purposes of this study, net primary productivity (NPP) is considered seedling
dry weight plus litterfall. Total nitrogen uptake includes nutrients accumulated in
aboveground and belowground biomass, and litterfall. An analysis of variance with
orthogonal contrasts was used to compare soil nutrient concentrations between sample
dates for each species with SAS
?
9.1. To compare litterfall differences between sampling
times within species, t-tests were performed with Bonferroni correction with SPSS
?
11.5.
60
RESULTS
Soil Chemical Analysis
The results of periodic soil sampling found there were some shifts in soil nutrient
levels from May to November (Tables 11 to 13). It was expected that the addition of
nitrogen fertilizers and organic matter would decrease pH and this may, in fact, have
occurred as average pH fell from 5.3 to 4.9 from May to the July sample for the three
species. An average pH of 4.9 to 5.3 is generally considered acidic for hardwood seedling
culture (Pritchett and Fisher, 1987). In spite of 246 to 289 kg N/ha added in the form of
mineral nitrogen fertilizer, soil nitrogen content remained constant. On the other hand,
inorganic fertilizer additions of 44 kg of P per hectare in the cultivation of Nuttall oak
and yellow poplar and 22 kg/ha in the cultivation of green ash significantly increased soil
P levels for all species. Average soil P content across the three species increased from
23.2 kg/ha in May to 28.5 kg/ha in September and November, an increase of 23%. With
one exception (Mg), soil K, Ca and Mg significantly decreased from May to November
for all three species. For example, soil Ca levels in May across all three species averaged
632 mg/kg, but had decreased to 417 mg/kg in November.
61
T
a
bl
e 11
.
S
o
i
l
c
h
e
m
i
c
a
l
a
n
a
l
y
s
i
s
f
o
r N
utt
a
l
l
o
a
k s
e
ed
l
i
ng
s
at
t
h
e T
e
nn
e
s
s
e
e
D
i
v
i
s
i
o
n
o
f
F
o
re
s
t
ry
dur
i
n
g
t
h
e 200
4 cr
o
p
s
e
a
s
o
n
M
o
nth S
p
ec
ies
p
H
O
.
M.
C
N
P
K
Mg
C
a
A
l
B
Cu
F
e
Mn
N
a
Z
n
Nu
t
t
al
l
o
a
k
Ma
y
5
.
2
17.
0
9.
7
0.
7
22
.
8
9
0.
5
54
.
3
60
2.
1
30
3.
7
0.
1
3.
5
47.
5
41.
1
2
7.
4
1.
6
July
4
.
7
17.
0
1
0.
0
0.
8
24
.
9
9
8.
6
45
.
8
49
9.
0
32
1.
6
0.
2
1.
9
59.
6
50.
5
2
5.
2
1.
6
Se
ptem
be
r
4
.
7
16.
5
9.
7
0.
8
32
.
3
8
7.
9
53
.
4
48
3.
4
34
2.
6
0.
2
3.
1
50.
1
56.
1
3
0.
8
1.
6
No
v
e
m
b
er
4
.
9
19.
0
1
1.
0
0.
8
27
.
7
7
1.
4
26
.
8
37
2.
2
33
4.
8
0.
2
1.
9
62.
3
50.
5
2
5.
0
1.
9
AN
O
V
A
Lin
e
ar
0.
03
0.
83
0
.
85
0.
91
<.
0
1
0
.
0
3
0.
86
0
.
08
<
.
0
1 0.
13 0
.
55
0.
33
0.
01
0
.
5
0
0.
64
Q
uadr
atic
<.
01
0.
71
0
.
22
0.
80
0.
0
3
0
.
0
2
0.
15
0
.
90
0
.
0
4 0.
46 0
.
79
<.
01
0.
00
0
.
7
0
0.
31
Lac
k
of
f
it
<.
01
0.
04
0
.
04
0.
24
0.
2
2
0
.
0
4
0.
01
<.
01
0
.
0
1
0.
13 0
.
11
<.
01
0.
02
0
.
6
0
0.
19
? ? ?
? g/k
g? ?
? ?
? ? ?
?
? ?
? ?
? ?
? ?
?
?
? ?
? ?
mg/kg? ? ?
? ?
?
? ?
?
?
? ?
? ?
? ?
?
?
62
T
a
bl
e 12
.
S
o
i
l
c
h
e
m
i
c
a
l
a
n
a
l
y
s
i
s
f
o
r
y
e
ll
o
w po
pl
ar s
e
ed
li
ngs
a
t
t
h
e T
e
n
n
es
s
e
e D
i
vi
s
i
o
n
o
f
F
o
res
t
r
y
du
r
i
n
g
t
h
e 2
004 cr
o
p
s
e
a
s
o
n
M
o
nth S
p
ec
ies
p
H
O
.
M.
C
N
P
K
Mg
Ca
Al
B
C
u
F
e
Mn
N
a
Z
n
Y
e
l
l
o
w
p
o
p
l
a
r
? ? ?
? g/k
g? ?
? ?
? ? ?
?
? ?
? ?
? ?
?
?
? ?
? ?
? ?
mg/k
g? ? ?
? ?
?
?
?
? ?
? ?
? ?
? ?
?
?
Ma
y
5
.
4
17.
0
1
0.
0
0.
7 28
.
4
111.
5
72.
8
627
.
4
349.
3
0.
1
4
.
3
35.
4
39
.
9
29.
7
1.
8
July
5
.
1
19.
4
1
1.
4
0.
8 32
.
5
117.
3
72.
9
509
.
3
342.
4
0.
1
3
.
5
40.
1
48
.
1
27.
9
1.
7
Se
ptem
be
r
5
.
0
18.
2
1
0.
7
0.
8 29
.
7
86.
5
43.
4
412
.
3
337.
2
0.
2
1
.
7
53.
3
52
.
8
24.
3
1.
8
No
v
e
m
b
er
5
.
1
18.
0
1
0.
6
0.
8 33
.
7
96.
5
66.
7
424
.
7
339.
0
0.
6
2
.
0
48.
6
57
.
4
27.
0
1.
6
A
N
OV
A
Lin
e
ar
0.
27
0.
49
0
.
48
0.
79 0.
7
2
<.
01
0.
01
0.
02
0.
37
0
.
0
2
0.
02
0.
05
<.
01
<.
01
0.
79
Q
uadr
atic
0.
06
0.
16
0
.
17
0.
31 0.
9
9
0.
60
0.
11
0.
13
0.
48
0
.
0
2
0.
39
0.
38
0.
12
<.
01
0.
34
Lac
k
of
f
it
0.
06
0.
32
0
.
32
0.
23 0.
0
6
0.
44
0.
70
0.
02
0.
37
<.
0
1
0.
08
0.
29
<.
01
0.
05
0.
03
63
T
a
bl
e 13
.
S
o
i
l
c
h
e
m
i
c
a
l
a
n
a
l
y
s
i
s
f
o
r gre
e
n
as
h
s
e
ed
li
ngs
a
t
t
h
e T
e
nn
es
s
e
e D
i
vi
s
i
o
n
o
f
F
o
res
t
ry
d
ur
i
n
g
t
h
e
2
004 c
r
o
p s
e
as
o
n
M
o
nth S
p
ec
ies
p
H
O
.
M.
C
N
P
K
Mg
Ca
Al
B
C
u
F
e
Mn
N
a
Z
n
G
r
e
e
n
a
s
h
? ? ?
? g/kg
? ?
?
? ? ?
?
? ?
? ?
? ?
?
?
? ?
? ?
? ?
mg/k
g? ? ?
? ?
?
?
?
? ?
? ?
? ?
? ?
?
?
Ma
y
5
.
4
17.
0
1
0.
0
0.
7 18
.
5
90.
7
66.
1
667
.
2
307.
4
0.
1
3
.
1
46.
6
54
.
0
28.
9
1.
5
July
5
.
1
18.
0
1
0.
6
0.
7 23
.
8
99.
4
54.
7
485
.
2
307.
6
0.
2
1
.
6
72.
9
85
.
6
24.
2
1.
3
Se
pte
m
be
r
5
.
1
18.
7
1
1.
1
0.
8 24
.
2
83.
7
47.
6
444
.
2
301.
4
0.
3
1
.
8
63.
8
59
.
4
25.
4
1.
1
No
v
e
m
b
er
5
.
1
19.
0
1
0.
8
0.
8 24
.
2
84.
3
48.
8
455
.
6
311.
7
0.
2
3
.
2
60.
8
55
.
5
25.
8
1.
9
A
N
OV
A
Lin
e
ar
0.
25
0.
29 0
.
28
0.
24
0.
0
7
<.
01
<.
01
<.
01
0.
29
<.
0
1
0.
81
0.
48
<.
01
0.
90
0.
80
Q
uadr
atic
0.
03
0.
36 0
.
36
0.
44
0.
0
1
0.
06
<.
01
<.
01
0.
12
<.
0
1
0.
10
0.
01
<.
01
0.
07
0.
02
Lac
k
of
f
it
0.
01
0.
45
0
.
45
0.
58
<.
0
1
0.
67
<.
01
<.
01
0.
17 0
.
0
2 0.
96
0.
02
0.
01
0.
09
0.
06
64
There were no significant trends in soil carbon and organic matter content (Tables
11 to 13) over the growing season (Table 10). Around 3.5 tons of carbon per hectare were
added to the soil through mulch application to green ash and yellow poplar growing
areas. What soil carbon content might have been without these additions is difficult to
ascertain. What is apparent, however, is that soil organic matter did not decline from May
to November. This may indicate the importance of litterfall and mulch in the maintenance
of soil organic matter in hardwood nurseries. From September to November, Nuttall oak,
yellow poplar, and green ash deposited 828, 3270, and 810 kg/ha, respectively, of dry
matter to the soil surface through litterfall (Table 20). Current seedling cultural practices
at the Tennessee Division of Forestry Nursery appears to be maintaining soil chemical
components, including soil organic matter levels, with the exception of soil Ca, Mg, and
K.
Litterfall is an important source of nutrients (Table 14). From July, when the
litterfall traps were first collected, to lifting time, the amount of nitrogen deposited by
litterfall was 21.9, 73.2, and 29.8 kg/ha for Nuttall oak, yellow poplar, and green ash,
respectively. This was equivalent to 8, 31, and 14 percent of the nitrogen applied as
fertilizer to Nuttall oak, yellow poplar, and green ash, respectively. Considering that
Nuttall oak had dropped only 34% of its leaves at the sample time in November, the
expected amount of nitrogen deposited on the nursery soil could be as much as 64 kg/ha.
Nitrogen and magnesium concentrations in the litterfall significantly decreased from
September to November for Nuttall oak and yellow poplar. Phosphorous concentration
decreased for yellow poplar while potassium increased for Nuttall oak. No macro-nutrient
changed from September to November for green ash.
65
T
a
bl
e 14.
M
acr
o an
d
m
i
cro
n
ut
r
i
e
n
t
co
n
cen
t
r
at
i
o
n
s
an
d depo
s
i
t
i
o
n
t
h
r
o
ug
h
h
a
r
d
woo
d
s
eed
l
i
ng
l
i
t
t
e
r
f
a
l
l
f
o
r
t
h
e 2004 cr
o
p
s
eas
o
n
N P
K
Ca
M
g
A
l
B
Cu
F
e
M
n
N
a
Z
n
Species
M
onth
? ? ?
? ?
? ?g/kg ?
? ?
? ?
?
?
? ? ?
? ?
? ?
? ?
? ?
? ?
?
mg/kg? ?
? ?
? ?
? ?
? ?
?
? ?
?
N
uttall oak
September
24.
6
*
0.
6
4.
2
9.
6
2.
0
*
1320.
6
*
27.
8
*
35.
7
*
775.
6
*
459.
1 220.
4
69.
5
(
1
.
2
) (
0
.
0
)
(
0
.
2
)
(
1
.
6
)
(
0
.
1
)
(
474.
6)
(
1
.
2
)
(
5
.
0
)
(
267.
2) (
148.
4)
(
54.
8)
(
1
.
7
)
November
12.
7
0.
6
4.
8
*
8.
4
1.
5
390.
0 18.
0
19.
5
234.
9
332.
1 199.
5
76.
0
(
2
.
0
) (
0
.
1
)
(
0
.
3
)
(
1
.
2
)
(
0
.
1
)
(
35.
9)
(
0
.
9
)
(
1
.
1
)
(
43.
8) (
141.
7)
(
34.
2)
(
16.
3)
Y
e
llo
w
poplar
September
17.
2
*
0.
6
*
8.
5 18.
5
3.
6
*
505.
1 19.
8
30.
0
297.
4
336.
4
217.
7
15.
8
(
0
.
8
) (
0
.
0
)
(
1
.
9
)
(
1
.
3
)
(
0
.
5
)
(
139.
2)
(
0
.
4
)
(
14.
2)
(
47.
4)
(
38.
1)
(
23.
1)
(
5
.
5
)
November
10.
2 0.
4
5.
1 15.
1
2.
6
426.
9 16.
0
21.
5
222.
9
302.
4
195.
0
12.
3
(
0
.
9
) (
0
.
1
)
(
1
.
6
)
(
1
.
8
)
0.
2
(
136.
5)
(
0
.
8
)
(
0
.
7
)
(
81.
5)
(
11.
6)
(
29.
6)
(
1
.
1
)
Gr
een as
h
September
26.
4 0.
7
3.
2 8.
6 1.
9
3637.
3
*
23.
5
99.
5
2428.
2
*
357.
7
*
316.
2
29.
7
*
(
5
.
3
) (
0
.
1
)
(
0
.
9
)
(
1
.
4
)
(
0
.
2
)
(
868.
6)
(
5
.
0
) (
46.
2)
(
539.
6)
(
87.
0)
(
142.
8)
(
8
.
0
)
November
17.
8 0.
8
3.
0
10.
1 1.
9
441.
3 23.
6
*
46.
7
427.
0 215.
2
147.
6
12.
1
(
1
.
9
) (
0
.
1
)
(
0
.
3
)
(
0
.
4
)
(
0
.
2
)
(
274.
3)
(
3
.
8
)
(
23.
3)
(
120.
9)
(
13.
9)
(
23.
9)
(
4
.
6
)
?
? ?
?
?
? ?
? ?
? ?
? ?
? ?
? ?
? ?
?
?
? ?
?kg/ha?
? ?
? ?
? ?
? ?
? ?
? ?
? ?
?
?
? ?
?
N
uttall oak
September
5.
5 0.
1
0.
9 2.
2 0.
5
0.
3
<.
1
<.
1
0.
2
0.
1
0.
1
<
.
1
November
16.
4 0.
8
6.
2
10.
9
2
0.
5
<.
1
<.
1
0.
3
0.
4
0.
3
0.
1
Y
e
llo
w
poplar
September
15.
6 0.
5
7.
7
16.
9 3.
2
0.
5
<.
1
<.
1
0.
3
0.
3
0.
2
<
.
1
November
57.
6
2.
3
28.
7 84.
8 14.
5
2.
4
0.
1
0.
1
1.
3
1.
7
1.
1
0.
1
Gr
een as
h
September
5.
9 0.
2
0.
7 1.
9 0.
4
0.
8
<.
1
<.
1
0.
5
0.
1
0.
1
<
.
1
November
23.
9 1.
1
4.
1
13.
6 2.
6
0.
6
<.
1
0.
1
0.
6
0.
3
0.
2
<
.
1
*
C
o
l
u
m
n
m
ean
s
ar
e s
i
gn
i
f
i
can
t
l
y
d
i
f
f
e
r
en
t
w
i
th
in
s
p
ec
i
es
a
t
th
e
0
.
0
5
l
e
v
e
l
u
s
in
g t
-
t
e
st
s
w
i
th
B
o
n
f
er
r
o
n
i
co
r
r
ec
t
i
o
n
.
1
S
t
a
n
d
a
r
d
e
r
ro
r
o
f
m
e
a
n
i
n
p
a
re
nt
he
s
i
s
66
Foliar nutrient concentrations averaged across the nursery growing season are
presented in Table 15. Values are similar across species, but not identical. There was a
strong trend for yellow poplar to have higher nutrient concentrations. In fact, average
yellow poplar nutrient concentrations were higher than both Nuttall oak and green ash for
N, P, K, Ca, and Mg. Average green ash nutrient concentrations were higher than Nuttall
oak for N, P, K, and Mg.
67
T
a
bl
e
15
.
A
v
e
r
ag
e
f
o
l
i
ar
se
ed
l
i
n
g
n
u
t
r
i
e
n
t
c
o
n
c
en
t
r
a
t
i
o
n
s
o
f
t
h
r
e
e h
a
r
d
wo
o
d
sp
ec
i
e
s
sa
m
p
l
e
d p
e
r
i
o
d
i
c
a
l
l
y
f
r
o
m
Ma
y
t
h
r
o
u
g
h
N
o
v
e
m
b
e
r
at
t
h
e T
en
n
ess
ee
D
i
vi
s
i
o
n
o
f
F
o
r
est
r
y
Nu
r
s
e
r
y
.
C N
P
K
Ca
M
g
AL
B
C
u
F
e
M
n
Na
Z
n
S
p
eci
e
s
?
?
?
? ?
?
?
?
?
?
?
g/
k
g ?
?
?
?
?
?
?
?
?
?
?
? ?
?
?
?
?
?
?
?
? ?
?
?
?
?mg/
kg
?
?
?
? ?
?
?
?
?
?
??
?
? ?
N.
O
ak
4
4
9.
2
1
8
.
8 1
.
5
8
.
4
6
.
8
1
.
7
41
7.
0
2
3.
0
20
.
2
28
2.
2
36
1.
8
21
9.
2
5
3
.
9
(
8
.
3)
(
1.
4
)
(
0.
2
)
(
2.
2
)
(
1.
3
)
(
0.
4
)
(
1
33
.
3
)
(
5
.
2)
(
1
2.
1)
(
1
05
.
2)
(
1
08.
6
)
(
86
.
7
)
(
1
9.
5
)
Y.
p
o
pl
a
r
4
2
9.
3
3
0
.
4 2
.
4
14
.
4
1
2
.
2
3
.
5
55
4.
7
2
0.
3
21
.
7
39
6.
3
26
4.
4
28
4.
9
2
5
.
0
(
7
.0
)
(
4
.
1
)
(
0
.5
)
(
3
.5
)
(
2
.
6
)
(
0
.5
)
(
5
4
1
.
9
)
(
6
.1
)
(
4
.0
)
(
3
6
0
.9
)
(
5
9
.
7
)
(
1
3
7
.
8
)
(
1
1
.8
)
G.
a
s
h
4
4
4.
9
2
6
.
4 2
.
1
14
.
7
6
.
0
1
.
9
33
0.
1
2
1.
8
24
.
2
32
3.
6
14
7.
6
19
3.
1
2
1
.
6
(
1
3
.
3
)
(
3
.3
) (
0
.4
)
(
3
.9
)
(
0
.
3
)
(
0
.2
)
(
3
9
0
.
6
)
(
3
.4
)
(
6
.8
)
(
2
2
7
.4
)
(
3
2
.
9
)
(
4
8
.
1
)
(
6
.3
)
?
St
a
n
d
a
rd
e
rro
r
o
f
t
h
e
m
e
a
n
i
n
p
a
re
n
t
h
e
si
s
68
NPK concentrations and contents in the seedling tissues
Average nitrogen, phosphorous, and potassium contents increased in the leaves
for the three species, primarily as a consequence of morphological growth (Figure 4).
However, nutrient concentration in the leaves of yellow poplar and green ash decreased
from May to September (Figure 1). This was probably due to translocation of nitrogen
and phosphorous from the leaves during the process of senescence in the fall, indicated
also by the decrease in nitrogen concentrations from September to November litterfall
samples (Table 14). The decrease in potassium for all species was evident but it may not
be completely linked to translocations since it is easily confounded with leaching.
Leaching of potassium greatly increases when the leaves turn yellow and cell turgor
decreases, resulting in considerable leaching before leaf fall (Witkamp, 1971). Nuttall
oak did not follow the same trend, possibly related to the warmer temperatures at the end
of the season, delaying leaf fall.
Average nitrogen concentrations in both stem and branches decreased from July
to September, probably due to tissue maturation during seedling development. There
were large increases in average stem nitrogen concentrations in the November sample
(Figure 2). This was probably due to translocation of nitrogen from the leaves during the
process of senescence in the fall. Seasonal variation in stem phosphorous concentrations
appeared to change by species. Potassium, on the other hand, showed declining stem
concentrations over the nursery season, which appeared to affect greatly yellow poplar
with a sharp decrease in the potassium content in the stems and branches (Figure 5).
Although roots had major biomass increases from September to November,
average root nitrogen increased for all three species (Figure 6), indicating no dilution
69
effect regarding their concentrations (Figure 3). In similar fashion to the aboveground
components, root phosphorous concentration seasonal changes varied by species. On the
other hand, root potassium concentrations did not seem to follow the same seasonal
changes as the aboveground components.
70
Figure1. Nitrogen, phosphorous, and pot
assium in the leaves of three hardwood sp
ecies grown at the Te
nnessee Division of
Forestry Nursery (NO=Nuttall oak, YP=yello
w poplar, GA=green ash) (Bars reported with
stand
ard error).
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
NO
Y
P
G
A
Sp
e
c
i
e
s
P h o s pho r o us ( g / kg )
05
10152025303540
NO
Y
P
G
A
Sp
e
c
i
e
s
N i t r oge n ( g/ k g )
Ma
y
Se
p
t
Ju
l
y
05
1015202530
NO
Y
P
G
A
Sp
e
c
i
e
s
P o t a s s iu m ( g /k g )
Se
p
t
No
v
Ju
l
y
Figure2. Nitrogen, phosphorous, and pot
assium in the stems and branches of thr
ee hardwood species grown at the Tennessee
Division of Forestry Nursery (
NO=Nuttall oak, YP=yellow poplar, GA=
green ash) (Bars reported with
stand
ard error).
02468
1012141618
NO
Y
P
G
A
Sp
e
c
i
e
s
P o ta s s iu m ( g /k g )
71
02468
10121416
NO
Y
P
G
A
Sp
e
c
i
e
s
Ni t r o g e n ( g / k g )
0
0.
51
1.
52
2.
5
NO
Y
P
G
A
Sp
e
c
i
e
s
P h os p h or o u s ( g / k g )
Se
p
t
No
v
Ju
l
y
Figure3. Nitrogen, phosphorous, and pot
assium in the taproot component of thre
e hardwood species grown at the Tennessee
Division of Forestry Nursery (
NO=Nuttall oak, YP=yellow poplar, GA=
green ash) (Bars reported with
stand
ard error).
02468
1012141618
NO
Y
P
G
A
Sp
e
c
i
e
s
P o ta ss i u m (g / k g )
0
0.
51
1.
52
2.
53
NO
Y
P
G
A
Spe
c
i
e
s
P ho s pho r o us ( g / kg )
02468
101214161820
NO
Y
P
G
A
Sp
e
c
i
e
s
N i t r oge n ( g/ k g)
72
Nuttall oak
0
20
40
60
80
100
120
May July Sept
Month
m
g
/s
e
e
d
lin
g
N
P
K
Yellow poplar
0
200
400
600
800
1,000
May July Sept
Month
m
g
/s
e
e
d
lin
g
N
P
K
Green ash
0
10
20
30
40
50
60
70
May July Sept
Month
m
g
/s
e
e
d
lin
g
N
P
K
Figure 4. Nitrogen, phosphorous, and potassium contents over time in the leaves of three
hardwood species grown at the Tennessee Division of Forestry Nursery (Data series
reported with standard error).
73
Nuttall oak
0
50
100
150
200
July Sept Nov
Month
m
g
/s
e
e
d
lin
g
N
P
K
Ye llow poplar
0
50
100
150
200
250
300
July Sept Nov
Month
m
g
/
s
e
e
d
lin
g
N
P
K
Green ash
0
20
40
60
80
July Sept Nov
Month
m
g
/s
e
e
d
lin
g
N
P
K
Figure 5. Nitrogen, phosphorous, and potassium contents over time in the branches and
stems of three hardwood species grown at the Tennessee Division of Forestry Nursery)
(Data series reported with standard error).
74
Nuttall oak
0
50
100
150
200
July Sept Nov
Month
m
g
/s
e
e
d
lin
g
N
P
K
Ye llow poplar
0
100
200
300
400
500
July Sept Nov
Month
m
g
/
s
e
e
d
lin
g
N
P
K
Green ash
0
20
40
60
80
100
July Sept Nov
Month
m
g
/s
e
e
d
lin
g
N
P
K
Figure 6. Nitrogen, phosphorous, and potassium contents over time in the roots of three
hardwood species grown at the Tennessee Division of Forestry Nursery (Data series
reported with standard error).
75
76
Translocation Efficiencies
The ability of a species to move nutrients from aging leaves so they can be used in
growing tissues is estimated by the resorption efficiency (RE). Calculations indicated that
yellow poplar had higher RE values for nitrogen and potassium when compared to both
green ash and Nuttall oak (Table 16). Yellow poplar appeared, therefore, to be the most
efficient at withdrawing nutrients from senescent leaves before abscission. Nutrients
withdrawn will normally be used for new growth or storage in the vegetative tissue until
the next growing season.
Table 16. Seedling resorption efficiency (RE) for three hardwood species produced in
the Tennessee Division of Forestry Nursery.
Species NP
? ? ? ? ? ? ? ? % ? ? ? ? ? ? ? ?
Nuttall oak 36.2 62.5
Yellow poplar 64.8 80.8
Green ash 23.1 53.0
Seedling translocation efficiency (TE) differs from RE in that it calculates the
amount of nutrient moved from senescent leaves in July into other plant organs. Nutrient
translocation in forest trees is an efficient strategy which makes the plants less dependent
on soil nutrient reserves, by optimizing the consumption of available nutrients within the
biogeochemical cycle (Colin-Belgrand, 1996). Yellow poplar, in this case, averaged
lower efficiencies when compared to the other two species. Nuttall oak had very high TE
values of 69 and 77 for nitrogen and phosphorous. Green ash translocation for both N and
P was relatively high.
77
Table 17. Seedling translocation efficiency (TE) for three hardwood species produced in
the Tennessee Division of Forestry Nursery.
Species NP
? ? ? ? ? ? ? ?% ? ? ? ? ? ? ? ?
Nuttall oak 69.3 77.5
Yellow poplar 22.9 61.8
Green ash 43.4 69.3
Seedling Nutrient Exports
Nutrient export occurs when seedlings are harvested during the lifting season and
their nutrient content removed from the nursery. The amount of nutrient export is a
function of both nutrient concentration and seedling size. Yellow poplar showed the
greatest level of export, primarily a function of its large size (Table 18), removing 233.6,
14.8, and 136.1 kg/ha of N, P, and K, respectively. Nuttall oak was second in the amount
of nutrients exported and green ash the third. The amount of nitrogen carried from the site
in green ash seedlings is only 36% of that removed by yellow poplar.
Even though there are significant amounts of fertilizer elements removed by
harvesting, the overall nitrogen and phosphorous balance is positive for all three species
(Table 19). There were 107, 18, and 153 kg/ha more nitrogen applied to Nuttall oak,
yellow poplar, and green ash, respectively, than removed through harvesting. Around
62% of all nitrogen applied to green ash was not exported from the nursery, indicating an
inefficient use of fertilizer materials when compared to the other two species. On the
other hand, yellow poplar nitrogen balance was slightly positive and phosphorous was
much higher than the other two species. Around 93% of all nitrogen applied to the
species was removed through harvesting while phosphorous removed was only 17%.
78
Ta
b
l
e
1
8
. M
a
c
ro
a
n
d
m
i
c
ro
n
u
t
ri
e
n
t
s
re
m
o
v
e
d
t
h
ro
u
g
h
h
a
rv
e
s
t
i
n
g
t
h
re
e
h
a
rd
w
o
o
d
s
e
e
d
l
i
n
g
c
ro
p
g
r
o
w
n
a
t
t
h
e
Te
n
n
e
s
se
e
D
i
v
i
s
i
o
n
o
f
F
o
re
s
t
ry
N
u
rs
e
r
y
.
C
N
P
K
Ca Mg
A
l
B
Cu
F
e
Mn
Na
Z
n
Sp
eci
e
s
?
?
? ?
? ?
? ? ?
? ?
? ?
? ?
? ?
? ?
? ?
? ?
?
k
g
/
h
a
?
?
? ?
? ?
? ?
? ?
? ?
? ?
? ?
? ?
? ?
?
?
? ?
N.
o
a
k
M
e
a
n
64
29
.
5
18
0.
1
17
.
1
9
3.
8
88
.
5
1
7.
1
6.
6
0
.
2
0
.
2
3.
7
3
.
3
3.
1
0.
6
M
i
n
60
25
.
9
12
6.
9
7
.
3
5
7.
2
36
.
8
1
1.
1
0.
5
0
.
1
0
.
1
0.
7
1
.
5
2.
3
0.
1
M
a
x
67
05
.
1
28
8.
7
28
.
7
15
6.
6
1
42
.
3 2
8.
2
2
4.
3
0
.
4
0
.
5 1
1.
3
6
.
9
5.
4
1.
3
Y
.
p
oplar
M
e
a
n
74
52
.
8
23
3.
6
14
.
8
13
6.
1
1
15
.
0
3
2.
8
8.
0
0
.
2
0
.
3
4.
9
2
.
5
3.
7
0.
2
M
i
n
69
15
.
2
15
9.
8
7
.
0
6
9.
7
54
.
7
2
1.
3
1.
0
0
.
1
0
.
2
0.
9
0
.
8
2.
8
<.
1
M
a
x
77
87
.
0
32
0.
0
23
.
4
28
0.
8
2
85
.
0 4
6.
5
2
8.
2
0
.
3
0
.
7 1
6.
8
5
.
4
5.
7
0.
5
G
.
as
h
M
e
a
n
32
41
.
6
8
6.
2
11
.
0
5
5.
3
40
.
1
1
0.
5
4.
1
0
.
1
0
.
2
4.
3
1
.
2
1.
5
0.
1
M
i
n
31
37
.
1
6
3.
7
5
.
0
1
9.
8
16
.
2 8.
1
0.
5
0
.
1
0
.
1 0.
6
0
.
4
0.
9
<.
1
M
a
x
33
75
.
1
14
6.
2
15
.
6
11
2.
8
77
.
6 1
5.
3
9.
5
0
.
2
0
.
5 1
2.
5
2
.
2
2.
6
0.
2
79
Table 19. Nitrogen and phosphorous balance for fertilizer application and removal
through the harvest of three hardwood species grown at the Tennessee Division of
Forestry Nursery
Nuttall oak Yellow poplar Green ash
------kg/ha-----
------kg/ha-----
------kg/ha-----
N P N P N P
Additions
Fertilizer
287 50 234 87 217 25
Mulch
0 0 17 1 22 1
Removal by harvesting
180 29 233 15 86 11
Balance
+107 +21 +18 +73 +153 +15
Nutrient Use Efficiencies
Yellow poplar had the lowest seedling density, and the highest aboveground and
belowground biomass, followed by Nuttall oak and green ash. Green ash produced only
39% of the biomass that Nuttall oak produced (Table 20). Phosphorous application
amounts varied by species, following the same pattern as that of biomass production.
Interestingly, species receiving higher phosphorous applications appeared to have more
growth.
Table 20. Nitrogen and phosphorus fertilization and seedling above and below ground
biomass for the three hardwood species produced at the Tennessee Division of Forestry
Nursery.
Species Seedlings N P Biomass Produced
N
o
/ha
1
kg/ha
2
? ? ? ? ? ? ? ? ? ? kg/ha ? ? ? ? ? ? ? ? ? ?
Above Below Litterfall Total
N. oak 520,968 287 50 7,952.6 6,560.6 828.9 15,342.1
Y. poplar 435,127 251 88 8,598.6 8,663.7 3269.3 20,531.6
G. ash 562,409 239 26 3,177.6 4,189.9 810.8 8,178.3
1
Considering 66% in seedling bed area;
2
Includes mulch application
Yellow poplar had the highest amount of biomass produced per unit of fertilizer
and organic nitrogen added to the soil (Table 21). For each kilogram of nitrogen added
per hectare in the form of fertilizer and mulch, yellow poplar produced 82 kg of biomass
per hectare (i.e. Partial Factor of Productivity), which included aboveground and
belowground seedling components as well as total seasonal litterfall. Nuttall oak
produced 53.5 kg of biomass for every kilogram of additional nitrogen, but green ash
only 34.5 kg (40 % of what yellow poplar produced). Interestingly, the NUE of Nuttall
oak was higher than that of yellow poplar. The crop NRE followed the same order as
PFP; however, with yellow poplar removal efficiency was very high. Green ash had the
lowest efficiencies ratings for PFP and NRE but relative high NUE.
Table 21. Seedling nitrogen partial factor of productivity (PFP), nitrogen use efficiency
(NUE), and crop nitrogen removal efficiency (NRE) for the three hardwood nursery
cultures samples in November
Species PFP NUE NRE (%)
Nuttall oak 53.5 75.9 62.8
Yellow poplar 81.8 66.9 93.0
80
Green ash 34.2 70.5 36.0
81
DISCUSSION
Soil Chemistry
There is little evidence to indicate that hardwood seedling culture modified the
nursery soil in any significant fashion over the course of the growing season. In fact,
organic matter, nitrogen, and carbon levels remained unchanged, indicating that
fertilization, litterfall, and the use of mulch all contribute to maintaining soil health.
Inorganic fertilization appeared to have maintained nutrient concentrations at satisfactory
levels throughout the season. However, soil Ca and Mg levels decreased and may be
related to inadequate fertilization. Nuttall oak and green ash exported 4 to 6 times more
Ca than 8 month old slash pine seedlings (Pritchett and Fisher, 1987). Litterfall is a major
component of hardwood nursery soil management. This study found an average litterfall
of 1,636 kg/ha (163.6 g/m
2
), returning 42, 2, and 16 kg of N, P, and K to the soil,
respectively, over the nursery season. A typical temperate deciduous forest will average
5400 kg/ha/yr of litterfall and return 61 and 42 kg of N and P, respectively (Cole and
Rapp, 1981). The annual litterfall rate for the fertilized nursery was around 30% that of a
mature deciduous forest and deposited around 70% as much as nitrogen.
The right amount of soil O.M. depends upon soil texture, drainage and climatic
factors. Generally, it should be 15 to 20 g/kg for sandy soils and 20 to 30 g/kg for heavier
soils (May, 1964). Maintenance of 40 g/kg to 50 g/kg organic matter in Oregon nursery
soils may be less difficult than maintaining 10 g/kg to 20 g/kg in southern Coastal Plain
soils (Pritchett and Fisher, 1987). There is a necessity of O.M. replacement on a regular
schedule for hardwood nurseries (Davey, 1984) and in this study may have been fulfilled
82
through litterfall deposition, which may have contributed to maintain O.M. levels at the
end of the season. Litterfall was an important source of soil carbon and organic matter,
and may have helped retain fertilizer elements from leaching, and buffered the soil
against rapid changes in acidity (Pritchett and Fisher, 1987). Without the nitrogen
deposited by litterfall, the total nitrogen removed by yellow poplar would be higher than
total fertilization.
Seedling Nutrition
All species were grown with similar nursery soil fertility protocols and nitrogen
application levels ranging close to the operational fertilization procedures described by
Stone (1980) with 280 kg/ha of N. The seedling bed density between 65-85/m
2
(Table 20)
was close to the density reported by Kormanick et al. (1997) for oaks but far behind that
recommended for yellow poplar by Williams and Hanks (1976), with bed densities of 110
seedlings/m
2
. Green ash bed density was slightly above the target of 57 seedling/m
2
reported by Kormanick et al. (1999). The apparent differences between the growth of
green ash and the other two species may be related to several factors. There is the
potential for an improper seed source, given the unknown origin of most hardwood seed
(Bonner, 1987). Relative low P levels in the soil for green ash (24 mg/kg P) may be
another reason for the lower growth. Lamar and Davey (1988) described that green ash,
isolated from low-P soils (5-7 mg/kg), grown in high fertility (148 mg/kg P) nursery soil
with VAM fungi significantly increased seedling height, RCD, and dry matter
accumulation. Moreover, phosphorus applied as a fertilizer for green ash was much lower
than the other two species and the lower translocation efficiency showed that this species
83
is more dependent on soil nutrients than the other two. Sometimes there are no symptoms
of P deficiency besides severe reduction in growth (Edwards, 1985). P levels increased in
the soil from May to November for all species, but its availability depends on pH. Acid
soil may result in fixation or precipitation of P as insoluble phosphates. Soil pH of 6.0 -
7.0 is preferable for hardwoods regarding P availability (Edwards, 1985). Some authors
consider the optimum range for many hardwood seedlings between 5.2 and 6.2 (Pritchett
and Fisher, 1987) and the pH of around 5 in this study might be considered low for most
hardwoods (Miller, 1999). However, given the adequate levels of available soil nutrients,
it is likely that pH did not have much affect on seedling growth.
Average foliar nitrogen concentrations in yellow poplar seedlings and green ash
seedlings decreased around 50% from May to late November. The reduction of N
applications after July while the seedlings were still growing may have resulted in a
?dilution? of N within the plant. Xue (2003) described that from the time of full leaf
expansion to the end of the growing season there is a decrease in N and P contents in the
leaves of most deciduous tree species. The N translocation efficiency for several species
ranged from 43-75% (Xue, 2003), which was slightly higher than the results of this study,
whereas their P translocation efficiency ranged from 62-84%, which was close for all
species in this study.
Kennedy (1988) found that one year old Nuttall oak and green ash seedlings had
N concentrations of 9.5 g/kg for shoots and 14.0 g/kg for roots, similar to the average of
12.0 g/kg found in this study for both species. Average green ash leaf nitrogen
concentration levels were similar to Villarrubia (1980), where foliar N varied from 24.0
g/kg to 29.0 g/kg.
84
This study indicates that hardwood seedlings export a much larger amount of
nutrients from the nursery than pine. Typical loblolly pine seedlings export 32 mg N per
seedling (South and Boyer, 1985), which at a typical spacing of 200 seedlings/m
2
is 6.4
g/m
2
of bed space. The current study found a nitrogen removal rate of 18, 23, and 9 g
N/m
2
for Nuttall oak, yellow poplar, and green ash, respectively. According to Pritchett
and Fisher (1987), slash pine seedlings from a Florida nursery, harvested at eight months
of age removed 5.3 g N/m
2
. This amount is half of that removed from the nursery by
green ash seedlings but four times less than yellow poplar. The high variability between
hardwood species nutrient requirements was noted by Davey (2005), who stated that
generally hardwoods require more nutrient that pine ? but not all hardwoods.
Resorption of nitrogen and phosphorous from senesced leaves were not highly
proficient in this study according to Killingbeck (1996), which considered resorption in
non-fertilized sites as highly proficient in plants when N and P in senescing leaves fell to
concentrations below 7.0 g/kg and 0.5 g/kg respectively. In this study, N concentration in
the senescing leaves was much higher for all species, especially for green ash, suggesting
that resorption may be a function of soil fertility with higher efficiency in infertile sites.
Green ash seems to be more dependent on current nutrient uptake from the soil than the
other two species. According to Singh (2004), fertilization decreases N and P resorption
efficiencies in all tree species.
It is notable that green ash may have a different nutrient use strategy than the
other two species of this study. The nutrient translocation efficiency value for green ash
fell between both Nuttall oak and yellow poplar, indicating this species utilized
considerable amounts of fertilizer elements without the need of higher resorption from
85
the leaves. Whether typical or a result of the growing conditions, the green ash sampled
in this study tended to recycle the major fertilizer elements within the seedling. Nuttall
oak growth strategies appeared to be based less on internal recycling than on soil uptake.
The translocation of nutrients in this study, in effect, combines the ideas that growth
potential and nutrient supply determine nutrient translocation (Munson et al., 1995).
Nutrient Use Efficiencies
Nutrient use efficiency values were comparable to the forest and agronomic crop
values gathered by J?rgensen and Schelde (2001) (Table 22). The NUE for Nuttall oak,
yellow poplar and green ash fell within the typical range for other species grown in
fertilized systems. Yellow poplar indicated lower nitrogen use efficiency under the
conditions of this study when compared to the other two species.
As the availability of a limiting nutrient increases, the mechanisms used by plants
to conserve that nutrient may become less efficient, resulting in lower NUE (Gray and
Schlesinger, 1983; Singh et al., 2005). Nutrient use efficiency calculations indicated a
higher utilization of the absorbed nitrogen for Nuttall oak, followed by green ash and
yellow poplar. The nitrogen concentration for yellow poplar was at normal levels
according to Villarrubia (1980). Thus, the higher yellow poplar nitrogen removal
efficiency and NUE may indicate the species has been adequately fertilized. The NUE for
Nuttall oak was quite high at 75.9%, yet the NRE of 62.8% and a PFP of 53.5, would
indicate that perhaps this species is being over-fertilized relative to its nitrogen use
efficiency and PFP. Yellow poplar had the highest NRE and smallest NUE. Although the
effects of nitrogen fertilization on nitrogen use strategies is not completely understood
86
(Aerts and Chapin, 2000), over fertilization may result in an increase in the growth of the
aboveground plant components relative to belowground.
Table 22. Nutrient use efficiencies for nitrogen of some forest trees and conventional
agricultural crops (Calculated for the aboveground material at harvest).
NUE Source
Poplar (Populus) 143-1000 (Jug et al., 1999)
Pine (Pinus) 100y 129 (Lodhiyal and Lodhiyal, 1997)
Wheat (Triticum) whole crop 83-87 (Jorgensen, 2000)
Potatoes (spp) 73 (Beale and Long, 1997)
Ryegrass (Lolium) 63 (Beale and Long, 1997)
Maize (Zea) 66-111 (Beale and Long, 1997)
Reed Canary grass (Phalaris) 43-78 (Geber, 2000)
NUE = Dry matter production/nitrogen content (g/g)
Source: adapted from J?rgensen and Schelde (2001)
Implications for Nursery Management
The results of this study indicate the high degree of complexity required of
hardwood seedling nutrition management. Hardwood species evolved under highly
variable environment and edaphic conditions. Nursery production systems may or may
not optimally address the needs of each species (or genera). This study found apparent
differences between species regarding fertilizer use efficiencies as well as strong
indications that the timing and amounts of fertilizers applications may need to vary by
species. How these nutritional characteristics may interact with other nursery cultural
practices such as seed source, sowing date, mulching, top-pruning, and undercutting,
needs to be further evaluated.
87
CONCLUSIONS
Yellow poplar, Nuttall oak and green ash cultivation resulted in small shifts in soil
nutrient levels from May to November. However, there were no changes in nitrogen, soil
carbon and organic matter content, probably as a result of mulch and leaf litterfall which
appeared to be very important in the maintenance of soil organic matter. In spite of
similar fertilization, some foliar nutrient concentrations averaged across the nursery
growing season varied by species.
Resorption of nitrogen and phosphorous from senesced leaves was not highly
efficient for all three species. Yellow poplar had higher resorption efficiency values for
nitrogen and phosphorous when compared to both green ash and Nuttall oak. On the
other hand, yellow poplar had much lower translocation efficiencies when compared to
the other two species, while green ash showed very high TE values. It?s notable that
green ash may have a different use strategy than the other two species, indicating this
species inefficiently removed nitrogen from the soil but efficiently utilized absorbed
fertilizer nitrogen; however, green ash seems to be the least efficient at withdrawing
nutrients from senescent leaves before abscission.
Yellow poplar showed the greatest level of nutrient export, primarily a function of
its large size. Nuttall oak was second in the amount of nutrients exported and green ash
third. Significant amounts of fertilizer elements were removed by harvesting. Nitrogen
and phosphorous balance (applied minus removed) was positive for all three species.
Yellow poplar had lowest amount of N left in the soil after harvesting, however, the
species had highest PFP and NRE.
88
Most Nuttall oak growth occurs in the fall, and fertilizer applications during this
period may improve its productivity. Green ash removed less nitrogen, and had relatively
high nitrogen use efficiency, but produced less biomass.
89
REFERENCES
Aerts, R. and Chapin, F.S. III. 2000. The mineral nutrition of wild plants revisited: A re-
evaluation of processes and patterns. Adv. Ecol. Res. 30: 1- 67.
AFC - Alabama Forestry Commission, 1997. Seedling care and reforestation standards.
November. [Online WWW]. Available URL:
?http://www.forestry.state.al.us/publication/pdfs/seedling%20care%20&%20refor
estation%20standards.pdf? [Accessed 15 Mach 2005].
Barnett, J.P. 2002. Trends in nursery research and production. In: Dumroese, R.K., Riley,
L.E. and Landis, T.D., tech. coords. National Proceedings: Forest and
Conservation Nursery Associations-1999, 2000, and 2001.Proceedings RMRS-P-
24. Ogden, UT: USDA Forest Service, Rocky Mountain Research Station: 97-
100.
Beale, C.V. and Long, S.P. 1997. Seasonal dynamics of nutrient accumulation and
partitioning in the perennial C4-grasses Miscanthus x giganteus and Spartina
Cynosuroides. Biomass and Bioenergy 12: 419-428.
Bonner, F.T. 1987. Collection and care of sweetgum seed, New Forests. 1(3): 207 - 214
Brown, K.R. 1999. Mineral nutrition and fertilization of deciduous broadleaved tree
species in British Columbia. B.C. Min. For. Res. Prog. Work. Pap. 42p.
Bruulsema, T.W. 2005. Enhancing fertilizer efficiency. Agri-Briefs Agronomic News
Items. Potash & Phosphate Institute N
o
1. Summer. [Online WWW]. Available
URL: ?http://72.14.203.104/search?q=cache:5youSTOiM8AJ:www.back-to-
basics.net/assets/agribriefs/Agri-BriefsSummer2005-
1.pdf+%22Enhancing+fertilizer+efficiency%22+bruulsema&hl=en&gl=us&ct=cl
nk&cd=1? [Accessed 11 July 2006].
Cassman, K.G., Dobermann, A., and Walters, D.T.2002. Agroecosystems, nitrogen-use
efficiency, and nitrogen management. Ambio. 31:132 - 140.
Cole, D. W. and Rapp, M. 1981. Elemental cycling in forest ecosystems. In D.E. Reichle
(ed.) Dynamic properties of forest ecosystems. Cambridge Univ. Press, Enagland.
pp. 341-409
Colin-Belgrand, M., Ranger, J., and Bouchon, J. 1996. Internal nutrient translocation in
chestnut tree stemwood. III. Dynamics across an age series of Castanea sativa
(Miller). Ann. Bot. 78: 729 - 740.
90
Davey, C.B. 1973. Artificial regeneration - bed treatment, fertilization, irrigation. In:
Hardwood Short Course. School of Forest Resources, North Carolina State
University, Industry Cooperative Program. pp. 53-59.
Davey, C.B. 1984. Nursery soil organic matter: management and importance. In: Duryea,
M.L. and T. D. Landis (eds.) Forest Nursery Manual. Martinus Nijhoff/ DrW.
Jung, The Hague, The Netherlands. pp. 81-86.
Davey, C.B. 1994. Soil fertility and management for culturing hardwood seedlings. Pp
38-49 in T.D. Landis and R.K. Dumroese (tech. coords.), National Proceedings:
Forest and Conservation Nursery Associations. Fort Collins, Colorado: USDA
Forest Service Rocky Mountain Forest and Range Experiment Station General
Technical Report RM-257.
Davey, C.B. 2005. Hardwood seedling nutrition. In: Dumroese, R. K., Riley, L. E., and
Landis, T. D., tech. coords. 2005. National proceedings: Forest and Conservation
Nursery Associations?2004; 2004 July; Charleston, NC and Medford, OR. Proc.
RMRS-P-35. Fort Collins, CO: U.S. Department of Agriculture, Forest Service,
Rocky Mountain Research Station.
Dumroese, R.K. 2003. Hardening fertilization and nutrient loading of conifer seedlings.
In: Riley, L.E., Dumroese, R.K., and Landis T.D., tech. coords. National
Proceedings: Forest and Conservation Nursery Associations?2002. Ogden, UT:
USDA Forest Service, Rocky Mountain Research Station. Proceedings RMRS-P-
28: 31?36.
Edwards, I.1985. How to maximize efficiency of fertilizers in a forest tree nursery. Forest
Nursery Proceedings. In: Intermountain Nurseryman's Association Meeting; 1985
August; Fort Collins, CO. Gen. Tech. Rep. RM-125. Fort Collins, CO; U.S.
Department of Agriculture, Forest Service, Rocky Mountain Forest and Range
Experiment Station; 1986. 111 pp.
Elliott, K.J. and White, A.S. 1993. Effects of competition from young northern
hardwoods on red pine seedling growth, nutrient use efficiency, and leaf
morphology. For. Ecol. Manage., 57:233-255.
Erdmann, G.G., Frederick, T.M., and Robert, R. O. 1979. Macronutrient deficiency
symptoms in seedlings of four northern hardwoods. USDA Forest Service,
General Technical Report NC-53. North Central Forest Experiment Station, St.
Paul, MN. 36 pp.
Geber, U. 2000. Nutrient removal by grasses irrigated with wastewater and nitrogen
balance for reed canarygrass. Journal of Environmental quality 29: 398-406.
Gray, J.T. and Schlesinger, W.H. 1983. Nutrient use by evergreen and deciduous shrubs
in southern California. J. Ecol., 71: 43-56.
91
Huggins, D.R. and Pan, W.L. 2003. Key indicators for assessing nitrogen use efficiency
in cereal-based agroecosystems. Journal of Crop Production. 8: 157-186.
J?rgensen, J.R. 2000. Wheat rye and triticale for energy ? input, yield and quality. In: Do
energy crops have a future in Denmark? (J?rgensen, U. ed.) DJF rapport
Markbrug nr. 29, 6-11. Denamark.
J?rgensen, U. and Schelde, K. 2001. Energy crop water and nutrient use efficiency.
Report for International Energy Agency, Paris, Bioenergy, Task 17
Jug, A., Hofmann-Schielle, C., Makeschin, F., and Rehfuess, K.E. 1999. Short-rotation
plantations of balsam poplars, aspen and willows on former arable land in the
Federal Republic of Germany. II Nutritional status and bioelement export by
harvested shoot axes. Forest Ecology and Management 121: 67-83.
Kennedy, H.E., Jr. 1988. Effects of seedbed density and row spacing on growth and
nutrient concentrations of nuttall oak and green ash seedlings. USDA Forest
Service Res. Note SO-349. 5 pp.
Killingbeck, K.T. 1996. Nutrients in senesced leaves: keys to the search for potential
resorption and resorption proficiency. Ecology 77: 1716?1727
Kormanik, P.P., Sung, S.S., and Kormanik, T.L. 1997. Genetics of Quercus. Proceedings
of the second meeting of working party 2.08.05 of the International Union of
Forest Research Organizations; 1997 October; University Park (State College).
pp. 194-200.
Kormanik, P.P., Kormanik, T.L., Sung, S.S., Zarnoch, S.J., and Possee, C. 1999.
Artificial regeneration of multiple hardwood species to develop specific forest
communities. In: Haywood, James D., ed. Proceedings of the tenth biennial
southern silvicultural research conference; 1999 February; Shreveport, LA. Gen.
Tech. Rep. SRS?30. Asheville, NC: U.S. Department of Agriculture, Forest
Service, Southern Research Station: 132?135.
Lamar, R.T. and Davey, C. B. 1988. Comparative effectivity of three Fraxinus
pennsylvanica Marsh. vesicular-arbuscular mycorrhizal fungi in a high
phosphorus nursery soil. New Phytol. 109:171 -181.
Lassoie, J.P., Hinckley, T.M., and Grier, C.C. 1985. Coniferous forest of the acific
northwest. In Chabot, B.F. & Mooney, H.A., eds. Physiological Ecology of North
American Plant Communities. New York: Chapman & Hall.
92
Lodhiyal, L.S. and Lodhiyal, N. 1997. Nutrient cycling and nutrient use efficiency in
short rotation, high density Central Himalayan Tarai poplar plantations. Annals
of Botany 79: 517-527.
Matherne, C. 2002. Propagating hardwood seedlings in Louisiana. In: National
proceedings: forest and conservation nursery associations - 1999, 2000, and 2001.
Dumroese, R.K., Riley, L.E., and Landis, T.D., tech. coords. USDA Forest
Service, Rocky Mountain Research Station, Proceedings RMRS-P-24, pp.234-
235.
May, J. T. 1984. Seedling, quality, grading, culling and counting. Chapter 9. Southern
Pine Nursery Handbook. USDA Forest Service Southern Region.
McNabb, K. 2004. Hardwood seedling production techniques in the southern United
States. In: Nursery production and stand establishment of broadleaves to promote
sustainable forest management, L. Cicarese, Ed. APAT, 2004. IUFRO S3.02.00.
Held May 7-10, 2001, Rome, Italy. pp. 83-88.
McNabb, K., Santos, H.Z. 2004. A survey of forest tree seedling production in the south
for the 2003-2004 planting season. Southern Forest Nursery Management
Cooperative, Technical Note 04-02. Auburn University. Auburn, AL.
Miller, S. 1999. Successful tree planting techniques for drastically disturbed lands: a case
study of the propagation and planting of container-grown oak and nut trees in
Missouri. Pages 157-171. IN: K. C. Vories and D. Throgmorton (eds), USDI, Off.
Surface Mining, and Coal Res. Center, Southern Illinois University (Sponsors),
Proc. Enhancement of Reforestation at Surface Coal Mines: Technical Interactive
Forum. Tree Physiol. 15: 141-149
Ntanos, D. A.and Koutroubas, S. D. 2002. Dry matter and N accumulation and
translocation for Indica and Japonica rice Mediterranean conditions. Field Crops
Res. 74: 93 - 101.
Pritchett, W. L. and Fisher, R.F. 1987. Properties and Management of Forest Soils. 2nd
ed. John Wiley and Sons, NY. 494 pp.
Singh, A. 2004. Effect of fertilization on N and P resorption efficiency of selected
leguminous and nonleguminous tropical trees planted on coal mine spoil. J. Indian
Inst. Sci., 84(5): 173-82.
Singh, S.P., Kiran B., Asha J., and Smita, C. 2005. Nitrogen resorption in leaves of tree
and shrub seedlings in response to increasing soil fertility research
communications. Department Of Botany, Kumaun University, Nainital 263 002,
Current Science. 89(2):25.
93
Smith, D.M. 1999 Hardwood seedlings as an alternative crop for small farms.
Agricultural Marketing Outreach Workshop Training Manual. USDA. Memphis,
TN. April 11-13, 2000
South, D.B. and Davey, C.B. 1983. The southern forest nursery soil testing program. Ala.
Agr. Esp. St. Cir. 265, 38 pp. Auburn University, Auburn, AL.
South, D.B. and Boyer, J.N. 1985. Nutrient content of nursery grown loblolly pine
seedlings. Ala. Agr. Exp. Sta. Circular 282, Auburn University, Alabama. 27 p.
South, D.B. and Donald, D.G.M. 2002. Effect of nursery conditioning treatments and fall
fertilization on survival and early growth of Pinus taeda seedlings in Alabama,
U.S.A. Canadian Journal of Forest Research. 32:1171-1179
South, D.B. and Carey, A.W. 2005. Weed control in bareroot hardwood nurseries. pp. 34-
38. In: Dumroese, R. K.; Riley, L. E.; Landis, T. D., tech. coords. 2005. National
proceedings: Forest and Conservation Nursery Associations?2004; 2004 July;
Charleston, NC and Medford, OR. Proc. RMRS-P-35. Fort Collins, CO: U.S.
Department of Agriculture, Forest Service, Rocky Mountain Research Station.
142 p.
Stone, E. L. 1968. Micronutrient nutrition of forest trees: A review. In: Forest
fertilization,theory and practice. pp. 132-75. Tenn. Valley Authority, Nat. Fert.
Dev. Center: Muscle Shoals, Alabama.
Stone, J.M. 1980. Hardwood seedling production: What are the fertility requirements? In:
Proceedings, North American forest tree nursery soils workshop. 1980. July 28-
August 1; Syracuse, NY. Washington, DC: U.S. Department of Agriculture,
Forest Service: 44-51.
Triebwasser, M.E. 2003. Fertilizer application: balancing precision, efficacy, and cost. In:
Riley, L. E., Dumroese, R. K. and Landis, T. D., tech. coords. National
proceedings: Forest and Conservation Nursery Associations?2003; 2003 June;
Coeur d?Alene, ID and Springfield, IL. Proc. RMRS-P-33. Fort Collins, CO: U.S.
Department of Agriculture, Forest Service, Rocky Mountain Research Station.
U.S.D.A. 1996. Soil survey of vermilion parish, Louisiana. Soil Conservation Service
Publication No. 1996-405-693/20014/SCS. Washington, D.C.: U.S. Government
Printing Office. 183 pp, 98 maps.
U.S. EPA. 2002. Methods for evaluating wetland condition: vegetation-based indicators
of wetland nutrient enrichment. Office of Water, U.S. Environmental Protection
Agency, Washington, DC. EPA-822-R-02-024.
94
Van Heerwarden, L. M., Toet, S., and Aerts, R. 2003. Current measures of nutrient
resorption efficiency lead to a substantial underestimation of real resorption
efficiency: facts and solutions. Oikos 664-669.
Villarrubia, J. M. 1980. Effect of nitrogen rate and source on growth and performance of
Liquidambar styraciflua (sweetgum) and Fraxinus pennsylvanica (green ash) in
aVirginia nursery [PhD dissertation]. Raleigh (NC): North Carolina State
University.
Williams, R.D. and Hanks, S.H. 1976 (slightly revised 1994). Hardwood nursery guide.
USDA Forest Service, Agriculture Handbook 473, 78 p.
Wilson, B.C. and Jacobs, D.F. 2004. Quality assessment of hardwood seedlings.
Hardwood Tree Improvement and Regeneration Center. Purdue University
Department of Forestry and Natural Resources. West Lafayette, Indiana. [Online
WWW]. Available URL:
?http://www.agriculture.purdue.edu/fnr/HTIRC/documents/BWilson2004.pdf?
[Accessed 11 July 2006].
Witkamp, M. 1971. Soils as components of ecosystems. Annual Review of Ecology and
Systematics. 2: 85 -110
Xue L., Luo, S., and Tan, T. 2003. Seasonal changes of nitrogen and phosphorus and
their translocation from leaves of ten tree species in central Japan. The Journal of
Applied Ecology. 14 (6):875-8.
95
AP
P
E
NDIX
T
a
bl
e
A
.
A
v
er
ag
e
ab
o
v
eg
r
o
un
d
n
u
t
r
i
e
n
t
co
n
c
en
t
r
at
i
o
n
s
o
f
N
u
t
t
a
l
l
o
a
k
see
d
l
i
n
g
c
o
m
p
o
n
e
n
t
s
gr
o
w
n
a
t
t
h
e
T
e
nn
es
see
D
i
v
i
si
o
n
o
f
F
o
r
e
s
t
ry
N
u
rs
e
r
y
.
N
C
C
a
K
M
g
P
Al
B
Cu
Fe
M
n
Na
Z
n
L
e
av
es
M
a
y
1.
9
0 4
3.
9
9
0
.
83
1.
18
0
.
23
0.
16
5
30
.
4
0
27
.
5
1
31
.
61
4
09
.
7
1
45
7
.
49
3
20
.
8
6
29
.
8
6
J
u
l
y
1.
8
0 4
4.
4
8
0
.
66
0.
75
0
.
18
0.
12
4
58
.
2
0
25
.
5
4
15
.
03
2
36
.
2
7
24
4
.
98
1
69
.
0
8
56
.
9
9
S
e
p
t
1.
9
8 4
5.
4
0
0
.
56
0.
78
0
.
16
0.
16
2
83
.
8
1
17
.
3
0
15
.
16
2
02
.
5
8
39
3
.
17
2
00
.
8
3
50
.
4
6
No
v
1.
8
1 4
5.
8
2
0
.
69
0.
64
0
.
12
0.
15
3
95
.
7
7 21
.
5
1
19
.
06
2
80
.
1
0
35
1
.
55
1
86
.
0
0 78
.
4
0
FO
B
1
Ma
y
2
1.
0
4 4
2.
2
1
0
.
71
1.
17
0
.
17
0.
13
2
11
.
8
0
16
.
6
1
19
.
00
1
62
.
5
4
16
1
.
66
3
00
.
3
2
14
.
9
2
J
u
l
y
1.
1
6 4
4.
1
3
0
.
55
1.
03
0
.
14
0.
11
94
.
1
1
16
.
7
9
14
.
13
1
04
.
7
4
16
2
.
73
1
99
.
5
3
45
.
5
6
S
e
p
t
0.
8
1 4
4.
3
2
0
.
58
0.
77
0
.
09
0.
10
1
65
.
6
9
14
.
8
9
18
.
43
1
20
.
7
8
35
3
.
46
1
91
.
5
7
25
.
7
2
No
v
1.
2
1 4
3.
3
5
0
.
29
0.
89
0
.
15
0.
14
1
,
4
92
.
73
24
.
4
3
20
.
93
7
24
.
0
2
16
2
.
40
2
91
.
7
1 26
.
8
1
St
e
m
Ma
y
2
1.
0
4 4
2.
2
1
0
.
71
1.
17
0
.
17
0.
13
2
11
.
8
0 16
.
6
1
19
.
00
1
62
.
5
4
16
1
.
66
3
00
.
3
2 14
.
9
2
J
u
l
y
0.
6
6 4
4.
1
9
0
.
79
0.
65
0
.
10
0.
06
95
.
7
2 12
.
1
7
16
.
53
1
03
.
9
8
13
5
.
15
1
93
.
3
3 26
.
5
4
S
e
p
t
0.
9
0 4
3.
9
6
0
.
79
0.
77
0
.
09
0.
11
11
9.
82
1
2.
78
1
4.
5
9
8
7.
93
2
99.
5
4
22
5.
95
1
8.
69
No
v
0.
9
0 4
4.
1
9
0
.
74
0.
44
0
.
09
0.
10
66
.
3
4 10
.
8
5
11
.
86
64
.
9
8
29
2
.
13
1
85
.
6
9 25
.
7
1
1
F
i
r
s
t
or
d
e
r
br
an
c
h
e
s
2
F
i
r
s
t
or
d
e
r
b
r
a
n
c
h
es a
n
d
s
t
e
m
co
m
b
i
n
ed
?
? ?
?
?
?
?
? ?
g/
k
g?
?
?
?
?
? ?
?
? ?
?
? ?
?
?
? ?
?
?
m
g/
kg?
?
?
?
? ?
?
?
?
?
96
T
a
bl
e
B
.
Av
e
r
age be
l
o
wgr
o
un
d n
u
t
r
i
e
n
t
co
n
c
en
t
r
a
t
i
o
n
s
o
f
Nut
t
a
l
l
o
ak se
e
d
li
ng c
o
m
p
o
n
e
n
t
s
gr
o
w
n
a
t
th
e T
e
nnes
s
ee
D
i
vi
s
i
o
n
o
f
F
o
r
e
s
t
ry
N
urs
e
r
y
.
N
C
Ca
K
M
g
P
Al
B
Cu
F
e
M
n
Na
Z
n
? ?
?
?
?
? ?
?
?
g/
kg?
?
?
?
? ?
?
?
?
? ?
? ?
?
?
? ?
?
?
?
?m
g/kg
? ?
? ?
?
?
? ?
? ?
?
?
?
FO
L
R
1
Ma
y
? ?
?
?
?
?
? ?
?
?
?
?
?
J
u
l
y
0.
9
7
4
4.
1
0
0.
36
0
.
60
0
.
11
0
.
0
7
2
,
79
5.
04
22
.
26
38.
0
5
1,
42
3.
6
2
157
.
31
3
13
.
6
3
43
.
62
Se
pt
1
.
18
43
.
01
0
.
2
9 0.
6
7 0.
1
2
0.
11
2
,
38
0.
66
15
.
54
27.
7
6
1,
17
0.
2
2
172
.
33
3
32
.
7
6
40
.
03
No
v
1.
0
4
4
4.
9
1
0.
71
0
.
56
0
.
09
0
.
1
1
8
2.
41
15
.
53
14.
1
7
5
9.
6
7
111
.
62
1
84
.
6
4
26
.
46
T
a
pr
oo
t
M
a
y
1.
0
8
4
0.
7
6
0.
26
0
.
83
0
.
11
0
.
1
5
2
,
72
2.
65
15
.
58
18
7.
5
5
1,
73
9.
2
1
126
.
90
3
42
.
7
3
34
.
28
J
u
l
y
1.
0
0
4
2.
8
7
0.
45
0
.
66
0
.
10
0
.
1
1
1
,
71
2.
85
11
.
67
23.
3
8
1,
10
8.
8
8
115
.
11
3
00
.
6
7
26
.
63
Se
pt
0
.
96
43
.
07
0
.
6
1 0.
8
1 0.
1
2
0.
12
87
2.
74
11
.
08
13.
9
3
44
0.
7
1
158
.
16
4
12
.
6
3
13
.
44
No
v
1.
2
2
4
1.
8
5
0.
39
0
.
87
0
.
11
0
.
1
6
29
6.
41
10
.
61
13.
6
9
17
0.
3
4
126
.
33
2
43
.
4
9
13
.
19
1
F
i
r
s
t
or
d
e
r
l
a
t
e
r
a
l
r
oot
s
97
T
a
bl
e C.
Av
er
ag
e
a
b
o
v
eg
r
o
un
d
n
u
t
r
i
e
n
t
c
o
n
c
en
t
r
at
i
o
n
s
o
f
y
e
l
l
o
w
p
o
pl
a
r
se
ed
l
i
ng
co
m
p
o
n
e
n
t
s gr
o
w
n
a
t
t
h
e
Te
n
n
e
s
s
e
e
D
i
v
i
si
o
n
o
f
F
o
re
s
t
ry
N
u
rs
e
r
y
.
N
C
Ca
K
M
g
P
A
l
B
Cu
F
e
M
n
Na
Z
n
L
e
av
es
M
a
y
3
.
36
4
2.
31
0.
8
2 2.
18
0.
4
4
0.
34
1,
7
33.
0
8
3
0.
4
2 2
5.
28
1
,
18
1.
41
22
6.
3
1
5
69.
1
8
32
.
3
6
J
u
l
y
3
.
06
4
3.
46
1.
1
5 1.
42
0.
3
3
0.
25
45
6.
7
8
2
2.
6
3 2
3.
32
3
43
.
61
23
8.
7
5
2
22.
0
8
33
.
9
3
S
e
p
t
2
.
91
4
2.
61
1.
4
2 1.
20
0.
3
4
0.
21
25
9.
8
2
1
4.
6
0 1
8.
92
1
87
.
30
30
2.
6
9
2
52.
9
4
13
.
6
3
No
v
?
?
? ?
? ?
?
?
?
?
?
?
?
FO
B
1
Ma
y
?
?
? ?
? ?
?
?
?
?
?
?
?
J
u
l
y
1
.
05
4
3.
05
0.
4
9 1.
54
0.
1
8
0.
17
1
41
.
47
18
.
96
16
.
0
5
13
7.
1
9
99
.
34
22
6
.
83
2
2.
61
S
e
p
t
0
.
75
4
2.
55
0.
5
7 1.
25
0.
1
4
0.
12
88
.
94
13
.
69
15
.
7
8
6
4.
3
5
1
50
.
63
31
6
.
85
9.
21
No
v
1
.
36
4
4.
85
0.
6
0 0.
65
0.
1
7
0.
08
11
2.
1
7
1
5.
6
5 1
2.
56
83
.
64
15
1.
1
3
2
07.
4
4
6
.
9
8
St
e
m
Ma
y
2
2
.
48
3
3.
83
0.
6
4 3.
17
0.
5
1
0.
58
6,
7
75.
6
5
2
9.
4
2 5
0.
44
4
,
74
8.
76
34
6.
2
9
9
86.
3
8
68
.
6
3
J
u
l
y
1
.
47
4
2.
90
0.
4
9 1.
39
0.
2
0
0.
19
1
94
.
05
14
.
95
17
.
1
3
17
2.
3
4
74
.
35
22
9
.
77
3
3.
88
S
e
p
t
0
.
72
4
3.
31
0.
4
9 0.
91
0.
1
1
0.
11
86
.
79
11
.
88
13
.
9
1
4
6.
4
1
85
.
93
23
7
.
12
7.
39
No
v
1
.
09
4
4.
57
0.
4
9 0.
50
0.
1
3
0.
09
10
6.
7
3
1
1.
9
8 1
6.
66
77
.
94
13
1.
3
0
2
04.
1
3
9
.
5
4
1
F
i
r
s
t
or
d
e
r
br
an
c
h
e
s
2
S
t
e
m
a
n
d ta
pr
oot
com
b
i
n
e
d
?
?
? ?
? ?
?
g
/
k
g
?
? ? ?
? ?
?
? ?
?
? ?
? ?
?
?
? ?
?
?
?
m
g/k
g?
? ?
? ?
?
?
? ?
?
?
?
?
98
T
a
b
l
e
D
.
Av
e
r
a
g
e
be
l
o
w
g
r
o
u
n
d
nu
t
r
i
e
nt
c
o
nc
e
nt
r
a
t
i
o
ns
o
f
ye
l
l
o
w
p
o
p
l
a
r
s
e
e
d
lin
g
c
o
m
p
o
ne
nt
s
g
r
o
w
n
a
t
t
he
Te
n
n
e
s
s
e
e
D
i
v
i
si
o
n
o
f
F
o
re
s
t
ry
N
u
rs
e
r
y
.
N
C
C
a
K
M
g
P
A
l
B
Cu
F
e
M
n
Na
Z
n
?
? ?
? ?
? ?
?
g
/
k
g
?
?
?
? ? ?
?
?
?
?
? ?
?
?
?
?
? ?
?
?
?mg/
kg
?
? ?
?
?
?
?
? ?
?
?
?
?
FO
L
R
1
Ma
y
?
?
? ?
? ?
? ?
?
?
?
?
?
J
u
l
y
1
.
62
42
.
97
0.
44
1
.
62
0.
31
0
.
28
3
,
80
0.
0
0
1
8
.
00
11
2.
2
4
2
,
52
8.
76
17
5.
6
6
4
24
.
7
8 60
.
63
Se
pt
1
.
21
42
.
04
0.
48
1
.
39
0.
29
0
.
15
1,
7
61
.
43
12.
4
7
43
.
50
1,
0
89
.
7
3
1
33
.
89
49
9.
67
2
7.
6
6
N
o
v
1
.
76
40
.
60
0.
38
1
.
47
0.
23
0
.
11
1,
3
35
.
13
11.
2
7
28
.
65
79
4.
0
0
97
.
80
27
8.
33
1
7.
9
8
Ta
p
r
o
o
t
Ma
y
2
2
.
48
33
.
83
0.
64
3
.
17
0.
51
0
.
58
6,
7
75
.
65
29.
4
2
50
.
44
4,
7
48
.
7
6
3
46
.
29
98
6.
38
6
8.
6
3
J
u
l
y
1
.
12
42
.
35
0.
38
1
.
20
0.
24
0
.
19
2,
3
01
.
00
13.
1
7
50
.
06
1,
5
89
.
7
8
1
23
.
30
36
5.
78
3
4.
4
4
Se
pt
1
.
15
42
.
06
0.
54
1
.
21
0.
27
0
.
15
1,
0
91
.
10
12.
2
4
28
.
37
72
7.
6
6
98
.
03
44
2.
33
1
7.
0
2
N
o
v
1
.
53
42
.
45
0.
35
0
.
81
0.
17
0
.
11
33
9.
8
1 6.
8
9
14
.
50
24
6.
9
3 54
.
05
18
4.
28
1
2.
9
5
1
F
i
r
s
t
o
r
d
e
r la
te
r
a
l
r
o
o
t
s
2
S
t
em
an
d
t
a
pr
oot
c
o
m
b
i
n
e
d
99
T
a
b
l
e
E
.
Ave
r
a
g
e
a
bo
ve
g
r
o
u
n
d
nu
t
r
i
e
nt
c
o
nc
e
nt
r
at
i
o
ns
o
f
g
r
e
e
n a
s
h s
e
e
d
l
i
n
g
c
o
m
p
o
ne
nt
s
g
r
o
w
n a
t
t
he
T
e
nn
e
s
s
e
e
D
i
v
i
s
i
o
n
o
f
F
o
re
s
t
ry
N
u
rs
e
r
y
N
C
C
a
K
M
g
P
Al
B
Cu
F
e
M
n
Na
Z
n
L
e
av
es
M
a
y
2.
87
44
.
09 0
.
63
2
.
17
0.
24
0
.
21
1,
2
09.
2
5
24
.
09
24
.
7
83
5.
77
1
27
.
19
254
.
77
20
.
72
J
u
l
y
2.
88
43
.
24
0.
6
1
.
59
0.
19
0
.
24
2
21.
8
7
24
.
47
2
9.
13
26
1.
54
1
74
.
04
217
.
17
26
.
79
Se
pt
2.
32
45
.
86 0
.
59
1
.
12
0.
18
0
.
17
14
5
.
36
1
8.
2
9 19
.
0
6
2
14
.
9
3
12
7.
8
8
1
4
8.
4
7
16
.
8
No
v
?
?
?
?
?
?
?
?
?
?
?
?
?
FO
B
1
M
a
y
?
?
?
?
?
?
?
?
?
?
?
?
?
J
u
l
y
1.
43
42
.
88 0
.
53
1
.
71
0.
16
0
.
16
1
46.
2
4
20
.
62
2
3.
89
16
7.
66
1
15
.
99
196
.
79
33
.
67
Se
pt
0.
78
40
.
43 0
.
64
1
.
12
0.
16
0.
1
3,
5
67.
1
9
3
6.
5
10
0.
16
1
0,
2
94.
9
6
1
72
.
74
213
.
96
279
.
43
N
o
v
1.
13
43
.
51 0
.
48
0
.
97
0.
15
0
.
17
4
16.
8
7
15
.
29
2
5.
28
36
8.
64
1
32
.
61
179
.
21
1
9.
3
St
e
m
Ma
y
2
1.
7
38
.
75
0.
5
2
.
94
0.
24
0
.
17
3,
1
50.
4
0
23
.
25
3
3.
34
1
,
94
4.
55
2
28
.
02
670
.
87
37
.
12
J
u
l
y
0.
95
43
.
42 0
.
34
0.
9
0.
13
0
.
14
66.
8
1
8
.
06
2
0.
85
8
3.
11
77
.
41
267
.
69
31
.
65
Se
pt
0.
73
42
.
78 0
.
45
0
.
64
0.
12
0.
1
20.
1
3
10
.
02
2
0.
98
7
5.
65
56
.
93
188
.
64
16
.
57
N
o
v
0.
95
44
.
61 0
.
55
0
.
62
0.
12
0
.
15
74.
7
2
13
.
74
2
3.
58
9
1.
13
75
.
64
197
.
81
8
.
76
1
F
i
r
s
t
or
d
e
r
br
an
c
h
e
s
2
St
em
a
n
d
t
a
p
r
o
o
t
co
m
b
i
n
ed
?
? ?
?
?
?
?
? ?
?
g/
k
g?
?
? ?
?
?
?
?
?
? ?
?
? ?
? ?
?
?
? ?
?
?
?
?
?m
g/kg
? ? ?
?
?
? ?
?
?
?
?
? ?
?
?
100
T
a
b
l
e
F.
A
ve
r
a
g
e
be
l
o
w
g
r
o
u
n
d
nu
t
r
i
e
nt
c
o
nc
e
nt
r
at
i
o
ns
o
f
g
r
e
e
n
a
s
h s
e
e
d
l
i
n
g
c
o
m
p
o
ne
nt
s
g
r
o
w
n a
t
t
he
T
e
nn
e
s
s
e
e
D
i
v
i
s
i
o
n
o
f
F
o
re
s
t
ry
N
u
rs
e
r
y
.
N
C
Ca
K
M
g
P
Al
B
C
u
F
e
M
n
N
a
Z
n
?
? ?
?
?
? ?
? ?
?
g/k
g?
?
? ?
?
?
?
?
? ?
?
?
? ?
? ?
? ?
? ?
? ?
m
g
/
k
g
?
?
? ?
? ?
? ?
? ?
? ?
FO
L
R
1
M
a
y
?
?
?
?
?
?
?
?
?
?
?
?
?
J
u
l
y
1
.
4
3 42
.
44
0
.
2
5 1.
1
4
0.
1
7 0.
16
3
,
23
5.
10
1
9.
8
2
4
9.
0
2
2
,
573
.
42
39
8.
9
2
3
82
.
77
38
.
8
3
Se
pt
0
.
9
9 41
.
92
0
.
3
1 0.
9
8
0.
1
8 0.
16
2
,
18
6.
49
1
5.
7
5
3
9.
9
3
2
,
254
.
18
30
3.
4
1
4
29
.
97
23
.
4
9
N
o
v
1
.
0
5 43
.
32
0
.
2
7 1.
3
4
0.
1
4 0.
17
1
,
27
8.
16
1
5.
3
4
3
7.
8
5
1
,
348
.
86
20
1.
7
1
3
01
.
47
19
.
4
8
Ta
p
r
o
o
t
Ma
y
2
1.
7 38
.
75
0.
5 2.
9
4
0.
2
4 0.
17
3
,
15
0.
40
2
3.
2
5
3
3.
3
4
1
,
944
.
55
22
8.
0
2
6
70
.
87
37
.
1
2
J
u
l
y
1
.
1
8 41
.
84
0
.
2
6 0.
9
3
0.
1
5 0.
15
2
,
41
6.
09
1
6.
9
7
4
0.
2
9
2
,
131
.
10
37
7.
9
4
3
28
.
89
26
.
9
1
Se
pt
0
.
7
3 41
.
99
0
.
2
7 0.
6
7
0.
1
2 0.
13
9
26
.
04
1
1.
1
4
2
7.
5
2
1
,
123
.
88
16
5.
9
5
3
11
.
81
17
.
4
9
N
o
v
0
.
9
1 42
.
86
0
.
3
6 0.
6
7
0.
1
2 0.
19
5
03
.
39
1
1.
6
8
3
0.
1
4
5
54
.
83 18
6.
6
3
2
00
.
28
11
.
6
3
1
F
i
r
s
t
o
r
de
r la
te
r
a
l
r
o
o
t
s
2
St
em
an
d
ta
p
r
o
o
t
c
o
m
b
i
n
e
d