PERFORMANCE OF SUGAR MAPLE TAXA (ACER SACCHARUM MARSH.) IN NORTH ALABAMA 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. _____________________________________ Kenneth Ray Blackwood Certificate of Approval: _________________________ _________________________ Charles H. Gilliam Jeff L. Sibley, Chair Professor Alumni Professor Horticulture Horticulture _________________________ _________________________ J. David Williams Stephen L. McFarland Professor and Head Dean Horticulture Graduate School PERFORMANCE OF SUGAR MAPLE TAXA (ACER SACCHARUM MARSH.) IN NORTH ALABAMA Kenneth Ray Blackwood 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 PERFORMANCE OF SUGAR MAPLE TAXA (ACER SACCHARUM MARSH.) IN NORTH ALABAMA Kenneth Ray Blackwood Permission is granted to Auburn University to make copies of this thesis at its discretion, upon request of individuals or institutions and at their expense. The author reserves all publication rights. _____________________________ Signature of Author _____________________________ Date of Graduation iv VITA Ken Blackwood, son of Carl Blackwood and Betty Blackwood, was born on April 15, 1961 in Hartselle, Alabama. After graduating from Falkville High School, Falkville, Alabama, 1979, he attended Auburn University in Auburn, Alabama. He received a Bachelor of Science Degree in Business Administration with emphasis in Industrial Operations Management in December 1983. After spending four years working as Personnel Manager for Sonoco Products Company in Granite Falls, North Carolina and in Decatur, Alabama, he attended Mid-America Baptist Theological Seminary in Memphis, Tennessee. He received a Masters of Divinity Degree in December 1991. He has served as pastor of First Baptist Church of Marvell, Arkansas and as pastor of First Baptist Church of Cuthbert, Georgia. In April 1997 he was appointed as career missionary of the International Mission Board of the Southern Baptist Convention. After studying Spanish at the Instituto de Lengua Espa?ol in San Jose, Costa Rica, he graduated with a diploma in Spanish. Since December 1998, he has served as a church planter in M?rida, Venezuela. In January 2006, he transferred to serve as a Strategy Coordinator in East Asia. In January 2002, he enrolled in the Graduate School at Auburn University. v THESIS ABSTRACT PERFORMANCE OF SUGAR MAPLE TAXA (ACER SACCHARUM MARSH.) IN NORTH ALABAMA Kenneth Ray Blackwood Master of Science, December 15, 2006 (M. Div. Mid America Baptist Theological Seminary, 1991) (B. S., Auburn University, 1983) 42 Typed Pages Directed by Jeff L. Sibley A sugar maple (Acer saccharum Marsh.) variety trial was initiated in March, 1999 at the North Alabama Horticulture Substation in Cullman, Ala. (USDA Zone 7). The purpose of the study was to identify superior sugar maple selections for landscape use in the Southeastern region of the United States, to evaluate growth (height and caliper increase), foliage characteristics (mean leaf area, petiole length, and chlorophyll content), and determine tolerance to the Japanese Beetle (Popillia japonica Newman). The study includes 22 sugar maple selections planted on a 6.1 m x 6.1 m (20 ft x 20 ft) spacing and fertilized with 454 g 13-13-13 per 2.54 cm (1 lb per 1 inch) of diameter at planting and in subsequent years in the winter months prior to budbreak. The study includes nineteen cultivars (?Astis? (Steeple?), ?Autumn Faith?, ?Autumn Blush?, ?Barrett Cole? (Apollo?), ?Bonfire? (Bonfire?), ?Commemoration?, ?Endowment?, ?Fairview? vi (Fairview?), ?Fall Fiesta? (Fall Fiesta?), ?Flax Mill Majesty?, ?Goldspire?, ?Green Mountain?, ?Legacy?, ?Morton? (Crescendo?), ?Reba? (Belle Tower?), ?Seneca Chief?, ?Sugar Queen?, ?Sweet Shadow Cut-Leaf?, and ?Moraine? (Wright Brothers?); and three sugar maple seedling selections (from A. McGill and Sons Nurseries, Gervais, OR; Ellenburg Nursery, Baileyton, AL; and J. Frank Schmidt and Son Nurseries, Boring, OR). ?Seneca Chief? had the greatest height increase at 73.41 cm (28.9 in.) while ?Barrett Cole? had the least annual height increase at 14.22 cm (5.6 in.). The largest caliper increase occurred with Ellenburg, a southern seedling source at 1.35 cm (0.5 in.) annual increase. Cultivars ?Barrett Cole? and ?Endowment? had the smallest caliper increase at 0.64 cm (0.25 in.) and 0.66 cm (0.26 in.), respectively. ?Goldspire? and the A. McGill seedling selection had the largest leaves followed closely by cultivar ?Green Mountain?. ?Commemoration? had the smallest leaves. ?Green Mountain? had the longest petioles at 13.1 cm (5.2 in.). ?Morton? had the shortest petioles at 6.7 cm (2.6 in.). ?Barrett Cole?, ?Autumn Blush? and ?Reba? had the least damage from Japanese Beetle, neither cultivar having any visible beetle damage. ?Fairview? ranked last with the greatest Japanese Beetle damage in this study with 2.8 from a possible 3.0 damage rating. ?Sweet Shadow Cut-Leaf?, with the most distinctive leaf of any selection in the study, ?Autumn Faith?, ?Green Mountain?, and ?Reba? had the highest chlorophyll content as determined by the SPAD-502 Leaf Greenness Meter. Using a Rating Index, the top five selections in our study were ?Green Mountain?, ?Reba?, ?Autumn Blush?, ?Sugar Queen? and ?Bonfire?. The selections with the poorest performance in our study, to date, were ?Barrett Cole?, ?Commemoration?, ?Fairview?, ?Legacy?, ?Morton?, and ?Moraine?. vii ACKNOWLEDGEMENTS The author would like to thank Dr. Charles H. Gilliam, Dr. J. David Williams and Dr. Jeff L. Sibley for their assistance on his committee, and for their patient guidance throughout his Master?s program. He also thanks David Cole and Jeff Wilson for their friendship and practical help during his course of study. Special thanks to Dr. Jeff Sibley for his friendship, motivation, wise council, and hard work to make this Master?s program possible under unusual circumstances. Gratitude is also expressed to Mr. Keith Warren at J. Frank Schmidt & Son Nurseries for providing the plant material and to the J. Frank Schmidt Charitable Trust for funds supporting this research. Very special thanks to his wife, Alison Blackwood for her constant and faithful love and support. Additionally, he offers thanks to Jesus Christ without whom his participation in this program would not have been possible. viii Style manual used: American Society for Horticultural Science Computer Software used: Microsoft Word 2002, Microsoft Excel 2002 and SAS v.9.1 ix TABLE OF CONTENTS LIST OF TABLES????...........??????????????....??....??.x I. INTRODUCTION AND LITERATURE REVIEW???...........?????..1 II. PERFORMANCE OF SUGAR MAPLE TAXA IN NORTH ALABAMA.......10 x LIST OF TABLES Chapter II: 1. Final height and average annual height increase for sugar maple selections in a North Alabama field trial?????..............................................................?.28 2. Final caliper and average annual caliper increase for sugar maple selections in a North Alabama field trial???????????????..?????.....29 3. Chlorophyll content, mean leaf area and mean petiole length for sugar maple selections in a North Alabama field trial??????????????.......30 4. Japanese beetle feeding preference among sugar maple selections in a North Alabama field trial ????????.??????????????.......31 5. Growth and quality summary rating index for sugar maple field trial in Cullman, Alabama (USDA Hardiness Zone 7) planted from 1998 to 2006?...????..32 1 CHAPTER I INTRODUCTION AND LITERATURE REVIEW Sugar maple (Acer saccharum Marsh) is well known as the source of the sweet sap used to make maple syrup and maple sugar. The lush canopy, vibrant autumn foliage, and distinctive bark also make sugar maple a prime selection as a home landscape tree (Ball, 2001). Sugar maple is often the dominant tree in deciduous forests of the Northeast, the popularity in that region attested to by its selection as the state tree for New York, Vermont, West Virginia, and Wisconsin (Calabrese, 1993). While over thirty named cultivars of A. saccharum have been selected (Dirr, 1998; van Gelderen et al., 1994), no southern selection is a dominant choice in the marketplace. A. saccharum has not been evaluated extensively as a landscape ornamental tree in the Southeastern United States, however, and limited information is available regarding the suitability of various sugar maple cultivars in this region (St. Hilaire and Graves, 1999). Currently almost all sugar maples available in the United States have been selected outside of the Southeastern United States and are sold as seedlings; or cultivars budded onto seedling rootstock. Differences in fall coloration among specific cultivars can be a determining factor for cultivar selection in landscapes where sugar maple thrives. Information on growth, pest resistance, viability, heat tolerance and required chilling to satisfy rest are additional criteria in need of evaluation in the Southeastern United States. Identification of superior 2 cultivars for use in the Southeast presents opportunities for an expansion of sugar maple production and landscape use in the region. Previous research of growth and development of A. saccharum has been limited to stands in the northern United States and in southern Canada. Effects of acid rain in eastern Canada and the Northeastern United States on sugar maple physiology, growth, and foliar nutrient concentrations have been studied (Hogan, 1998; Laurence et al., 1996). Stomatal conductance models for sugar maple have been studied on trees in Vermont (Yang et al., 1998). Leaf characteristics have long been broadly used as diagnostic characters in the genus Acer (Desmarais, 1952). This very common and variable tree has attracted the attention of many taxonomists and since 1753 it has been described under at least 17 specific, 18 varietal, and 18 formal names in more than 97 different combinations. However, the leaf itself is the character that shows the most striking variations and therefore is used most predominately as a reference point when describing the range, viability and distribution of Acer (Desmarais, 1952). Observations conducted in the Sipsey Wilderness in Northwestern Alabama ranked A. saccharum as one of the top ten ecological species based on basal area (Zhang et al., 1999). However, at present, there are no reports for cultivar evaluations for landscape use in Alabama and the Southeast. Studies have shown sugar maple to have an obligate chilling requirement, and therefore the species typically will only have one flush of growth in a growing season (Wood and Hanover, 1981). Although there are several cultivars with marketable names, there is little basis for promoting any particular cultivar in Southeast USDA Zones 7 to 8. 3 Sugar maple has difficulty thriving in urban bricked walkways (Schwets and Brown, 2000). Although Acer saccharum survived for up to 25 years when planted in a brick walkway, the surviving trees had lower canopy densities, higher amounts of twig die-back, and smaller canopy widths compared to trees planted in turfed areas, which performed better and were able to maintain form and structure. Those planted in a bricked walkway were more open-canopied and ragged in appearance when compared to those grown in turfed areas (Schwets and Brown, 2000). A buried-pot study of 2-year-old sugar maple seedlings conducted in the Northeastern United States to test how liming influences growth and nutrient balances of this species showed a 37% larger growth on trees where lime was incorporated into the soil than non-limed control seedlings (Burke and Raynal, 1998). However, seedlings that received surface lime treatments were 9% smaller than control seedlings. Seedlings for this study were planted on May 9 and were harvested on August 30 of the same year. There is little information on the long-term effects of liming for A. saccharum. Sugar maple use in areas where there is exposure to drying winds may be limited due to its sensitivity to desiccation (Cogliastro et al., 1997). Poor growth was observed for A. saccharum when situated on an elevated rise with no windbreak, even though the site had moderately well drained soil thus preventing ?wet feet?. Effect of wind on leaf size has been documented (Niklas, 1996). The influence of mechanical stimulation on the properties of mature Acer saccharum leaves was clearly discernible. Leaves harvested from a sapling growing in a windy site were smaller in every measured respect compared with their closed site counterparts. 4 In a study conducted in northwest Connecticut (Finzi and Canham, 2000), six species under varying light and nitrogen (N) conditions were evaluated. Only red maple (Acer rubrum L.) and sugar maple (Acer saccharum) showed growth rates significantly related to N availability, where N availability increased sugar maple growth under low light but did not change growth under high light (Finzi and Canham, 2000). Twenty-five percent or less of the variation in sugar maple sapling growth was attributed to variation in light availability and nitrification. Roadside sugar maple trees in urban areas suffer localized root mortality due to severely limited infiltration rates and gaseous exchange in devegetated and compacted soils along roadways (Ruark et al., 1983). These adverse conditions are most common along roadsides in northern latitudes where salt is used to melt snow. After several years the ground succumbs to these adverse conditions and the site is denuded. Surface soil crusts may develop from raindrop impact as well as physical trampling of this devegetated soil (Ruark et al., 1983). However, roadside conditions in southern climes might be more accommodating to sugar maple because of the lessened frequency of salt application. This needs further study. Close et al. (1996) conducted a study demonstrating the sensitivity of sugar maple to water deficits. Pair (1993) has shown that certain cultivars of sugar maple have a greater tolerance to drought stress. Few studies have evaluated sugar maple response to insect damage. Damage from pear thrips (Taeniothrips inconsequens Uzel) has been noted on sugar maple (Gale Group, 1992). The tiny, comma-sized insect bores into the buds where the tender, folded 5 leaves are vulnerable. In 1988 pear thrips caused the defoliation of a half million acres of maple forest in Vermont. Damage to landscape trees from Japanese beetles (Popillia japonica Newman) has increased dramatically in recent years in the Southeast (Pettis et al., 2005). The southern movement of Japanese beetles has been documented (NAPIS, 2003), creating a need to determine Japanese beetle feeding preferences for the landscape (Gu et al., 2005; Held, 2004; and Stafne et al., 2005). The most comprehensive study to date (Held, 2004) on susceptibility to Japanese beetle across a wide range of woody landscape plants noted that some species of Acer have demonstrated resistance to Japanese beetle. However, distinction of cultivar specific resistance for A. saccharum selections was not a part of the study (Held, 2004). Experiments were conducted in Griffin, GA to evaluate the suppression of naturally occurring Japanese beetles and crapemyrtle aphids (Tinocallis kahawaluokalani Kirkaldy) on containerized ?Muskogee? crapemyrtles (Lagerstroemia spp.) (Pettis et al., 2005). Both a field trial and a screen house trial were conducted. Eleven insecticides were evaluated in the field trial and seven insecticides were evaluated in the screen house trial. Greatest reduction in Japanese beetle damage was evident with Talstar (bifenthrin) and Scimitar (lambda-cyhalothrin). Additionally, Tame (fenpropathrin), a synthetic pyrethroid, resulted in moderate to good control of both Japanese beetle and crapemyrtle aphid. Whether these same insecticides might prove useful in the suppression of Japanese beetle on A. saccharum is yet to be determined. Sugar maples are among the more valued landscape trees throughout the United States due to fall color, crown shape, and relatively few disease or pest problems. 6 However, most cultivars have been selected for traits other than stress and insect tolerance. For example, ?Sweet Shadow Cut-Leaf? has the most unusual leaf shapes of any sugar maple in the marketplace. The species has also been noted to have larger leaves from more northern climes than those populations found in the southern part of the native range (Desmarais, 1952). Many criteria are used to evaluate a tree?s landscape value. In the future, one of the great concerns for homeowners will be pest tolerance. Determination of suitable sugar maple selections for the Southeast with regard to insect feeding preference in addition to growth and environmental response will provide valuable information for producers and the landscape industry. 7 Literature Cited Ball, J. 2001. The savory sugar maple. Amer. Forests, Vol. 106, No. 4:45-46. Burke, M.K., and D.J. Raynal. 1998. Liming influences growth and nutrient balances in sugar maple (Acer saccharum) seedlings on an acidic forest soil. Environ. and Expt. Botany 39:105-116. Calabrese, D.M. 1993. A geography of state trees. Amer. Forests, Vol. 99, No. 2:35-37. Close, R.E., J.J. Keilbaso, P.V. Nguyen, and R.E. Schutzki. 1996. Urban vs. natural sugar maple growth: II. Water relations. J. of Arboric. 22:187-192. Cogliastro, A., D. Gagnon, and A. Bouchard. 1997. Experimental determination of soil characteristics optimal for the growth of ten hardwoods planted on abandoned farmland. For. Ecol. and Manag. 96:49-63. Desmarais, Y. 1952. Dynamics of leaf variation in the sugar maples. Brittonia, Vol. 7, No. 5:347-387. Dirr, M.A. 1998. Manual of Woody Landscape Plants: Their Identification, Ornamental Characteristics, Culture, Propagation and Uses. Stipes Publishing, Champaign, IL. 53-57. Finzi, A.C. and C.D. Canham. 2000. Sapling growth in response to light and nitrogen availability in a southern New England forest. Forest Ecology and Management 131:153-165. Gale Group. 1992. The biggest sugar maple. Amer. Forests, Vol. 98, No. 1:11-12,43. Gu, M., J.A. Robbins, C.R. Rom, and J. McAfee. 2005. Japanese beetle (Popillia japonica Newman) feeding preference on birch taxa (Betula). HortScience 40:873. 8 Held, D.W. 2004. Relative susceptibility of woody landscape plants to Japanese beetle (Coleoptera : Scarabaeidae). J. Arboric. 30:328-335. Hogan, G.D. 1998. Effect of simulated acid rain on physiology, growth and foliar nutrient concentrations of sugar maple. Chemosphere, Vol. 36, No. 4-5:633-638. Laurence, J.A., R.J. Kohut, R.G. Amundson, D.A. Weinstein, and D.C. MacLean. 1996. Response of sugar maple to multiple year exposures to ozone and simulated acidic precipitation. Environ. Pollution, Vol. 92, No. 2:119-126. National Agricultural Pest Information System. 2003. Last accessed 6/1/2005. www.ceris.purdue.edu/napis/pests/jb/imap/jb2003.html. Niklas, K.J. 1996. Differences between Acer saccharum leaves from open and wind- protected sites. Annals of Bot. 78:61-66. Pair, J.C. 1993. Growth and stress tolerance of sugar maple cultivars. Kansas St. Uni., Wichita Hort. Res. Ctr. Report of Progress #693. Pettis, G.V., S.K. Braman, L.P. Guillebeau, and B. Sparks. 2005. Evaluation of insecticides for suppression of Japanese beetle, Popillia japonica Newman, and crapemyrtle aphid, Tinocallis kahawaluokalani Kirkaldy. J. Environ. Hort. 23:145-148. Ruark, G.A., D.L. Mader, P.L.M. Veneman, and T.A. Tatter. 1983. Soil factors related to urban sugar maple decline. J. of Arboric. 9:1-6. Schwets, T.L. and R.D. Brown. 2000. Form and structure of maple trees in urban environments. Landscape and Urban Planning 46:191-201. St. Hilaire, R., and W.R. Graves. 1999. Foliar traits of sugar maples and black maples near 43?N latitude in the eastern and central United States. J. Amer. Soc. Hort. Sci. 124:605-611. 9 Stafne, E.T., J.R. Clark, D.T. Johnson, and B.A. Lewis. 2005. Foliar damage of blackberries and blueberries by Japanese beetle (Popillia japonica). HortScience 40:879. van Gelderen, D.M., P.C. de Jong, and H.J. Oterdoom. 1994. Maples of the World. Pgs. 327-330. Timber Press, Portland, OR. Wood, B.W., and J.W. Hanover. 1981. Environmental control of sugar maple seedling growth. Research Report ? Michigan State Univ. Agric. Expt. Stat., Jan. 1981:1-10. Yang, S., X. Liu, and M.T. Tyree. 1998. A model of stomatal conductance in sugar maple (Acer saccharum Marsh.). J. Theor. Biol. 191:197-211. Zhang, L., B.P. Oswald, and T.H. Green. 1999. Relationships between overstory species and community classification of the Sipsey Wilderness, Alabama. For. Ecol. and Manag. 114:377-383. 10 CHAPTER II PERFORMANCE OF SUGAR MAPLE TAXA IN NORTH ALABAMA Abstract: A sugar maple (Acer saccharum Marsh.) variety trial was initiated in March 1999 at the North Alabama Horticulture Substation in Cullman, Ala. (USDA Cold Hardiness Zone 7). The purpose of the study was to identify superior sugar maple selections for landscape use in the Southeastern region of the United States, to evaluate growth (height and caliper increase), foliage characteristics (mean leaf area, petiole length, and chlorophyll content), and determine tolerance to the Japanese Beetle (Popillia japonica Newman). The study includes 19 named sugar maple cultivars planted on a 6.1 m x 6.1 m (20 ft x 20 ft) spacing and fertilized with 59 g of nitrogen (N), 25 g of phosphorus (P), and 49 g of potassium (K) as 13N ? 5.6P 2 O 5 ? 10.8K 2 O (13-13-13) per 2.54 cm (1 inch) of diameter (caliper) at planting and in subsequent years in the winter months prior to budbreak. The 19 cultivars (?Astis? (Steeple?), ?Autumn Faith?, ?Autumn Blush?, ?Barrett Cole? (Apollo?), ?Bonfire? (Bonfire?), ?Commemoration?, ?Endowment?, ?Fairview? (Fairview?), ?Fall Fiesta? (Fall Fiesta?), ?Flax Mill Majesty?, ?Goldspire?, ?Green Mountain?, ?Legacy?, ?Morton? (Crescendo?), ?Reba? (Belle Tower?), ?Seneca Chief?, ?Sugar Queen?, ?Sweet Shadow Cut-Leaf?, and ?Moraine? (Wright Brothers?); and three sugar maple seedling selections (from A. McGill and Sons Nurseries, Gervais, OR; Ellenburg Nursery, Baileyton, AL; and J. Frank Schmidt and Son Nurseries, Boring, OR) provide the largest collection of sugar maple germplasm 11 in the United States. ?Seneca Chief? had the greatest annual average height increase at 73.41 cm (28.9 in.) per year while the ?Barrett Cole? (Apollo TM ) cultivar had the least annual height increase at 14.22 cm (5.6 in.). The largest caliper increase was measured in Ellenburg, a southern seedling source at a 1.35 cm (0.5 in.) annual increase. Two cultivars (?Barrett Cole? (Apollo TM ) and ?Endowment?) had the smallest caliper increase at 0.64 cm (0.25 in.) and 0.66 cm (0.26 in.), respectively. ?Goldspire? and the A. McGill seedling selection had the largest leaves followed closely by cultivar ?Green Mountain?. ?Commemoration? had the smallest leaves. ?Green Mountain? had the longest petioles at 13.1 cm (5.2 in.). ?Morton? (Crescendo?) had the shortest petioles at 6.7 cm (2.6 in.). ?Barrett Cole? (Apollo TM ), ?Autumn Blush? and ?Reba? (Belle Tower TM ) had the least damage from Japanese Beetle, neither cultivar having any visible beetle damage. ?Fairview? ranked last with the greatest Japanese Beetle damage in our study with 2.8 from a possible 3.0 damage rating. ?Sweet Shadow Cut-Leaf?, with the most distinctive leaf of any selection in the study also had the highest chlorophyll content as determined by the SPAD-502 Leaf Greenness Meter. Using a Rating Index, the top five selections in our study were Green Mountain R , ?Reba? (Belle Tower?), ?Autumn Blush?, ?Sugar Queen? and ?Bonfire? (Bonfire?). The selections with the poorest performance in our study, to date, were ?Barrett Cole? (Apollo TM ), ?Fairview? (Fairview?), ?Commemoration?, ?Legacy?, ?Morton? (Crescendo?), and ?Moraine? (Wright Brothers?). This study is the first to report on performance of sugar maples as a landscape tree in the Southeastern United States. 12 Introduction Demand for ornamental plants and trees for use in private landscapes is a multimillion-dollar business. Suppliers of landscape materials providing consumers with hardy, insect and disease resistant, and aesthetically pleasing ornamental plants and trees fill a market niche that has explosive financial potential. Sugar maple (Acer saccharum) is considered a prime selection as a home landscape tree due to its characteristic lush canopy, vibrant autumn foliage, and distinctive bark (Ball, 2001). While over thirty named cultivars of A. saccharum have been selected (Dirr, 1998; van Gelderen et al., 1994), no southern selection is a dominant choice in the marketplace. Identification of superior cultivars in the southeast presents opportunities for an expansion of sugar maple production and landscape use in the region. Expansion of this market into new geographical areas will mean more potential profits for nurseries seeking to meet the consumer demand. Taxonomy and Growth Habit The species Acer saccharum belongs to the Aceraceae family of the order Sapindales of the Magnoliophyta division. Native to North America, sugar maple is a large tree averaging from 60 feet to 100 feet in height, with a trunk diameter from 2 to 4 feet. Sugar maple has a large, lush canopy measuring 40 feet to 60 feet in width and offering vibrant fall foliage. Although sugar maple is a hardwood and resistant to storm damage, this species prefers well-drained soils and is not generally tolerant of crowded or polluted conditions (Dirr, 1998; Radford et al., 1968). The effects of acid rain in Eastern Canada and the Northeastern United States on sugar maple physiology, growth, and foliar nutrient concentrations have been studied (Hogan, 1998; Laurence et al., 1996). 13 Although there are several cultivars with marketable names, A. saccharum has not been evaluated extensively as a landscape ornamental tree in the Southeastern United States and limited information is available regarding the suitability of various sugar maple cultivars in this region (St. Hilaire and Graves, 1999). Observations conducted in the Sipsey Wilderness in Northwestern Alabama ranked A. saccharum as one of the top ten ecological species based on basal area (Zhang et al., 1999). Stomatal conductance models for sugar maple have been studied on trees in Vermont (Yang et al., 1998). However, at present, there are no reports for cultivar evaluations for landscape use in Alabama and the Southeast, and therefore there is no basis for promoting any particular cultivar in Southeast USDA Zones 7 to 8. Previous research of growth and development of A. saccharum has been limited to stands in the northern United States and in southern Canada. Currently almost all sugar maples available in the United States have been selected outside of the Southeastern United States and are sold as seedlings or cultivars budded onto seedling rootstock. Japanese Beetle predation is a critical factor in the selection of sugar maples for landscape use. Although damage to landscape trees from Japanese beetles (Popillia japonica) has increased dramatically in recent years in the Southeast (Pettis et al., 2005), no study to date to has determined cultivar specific resistance to Japanese Beetle for A. saccharum selections. The southern movement of Japanese beetles has been documented (NAPIS, 2003), creating a need to determine Japanese beetle feeding preferences for the landscape (Gu et al., 2005; Held, 2004; and Stafne et al., 2005). Experiments were conducted in Griffin, GA to evaluate the suppression of naturally occurring Japanese beetle (Popillia japonica) and crapemyrtle aphid (Tinocallis 14 kahawaluokalani Kirkaldy) on containerized ?Muskogee? crapemyrtles (Lagerstroemia spp.) (Pettis et al., 2005). Both a field trial and a screen house trial were conducted. Eleven insecticides were evaluated in the field trial and seven insecticides were evaluated in the screen house trial. Greatest reduction in Japanese beetle damage was evident with Talstar (bifenthrin) and Scimitar (lambda-cyhalothrin). Additionally, Tame (fenpropathrin), a synthetic pyrethroid, resulted in moderate to good control of both Japanese beetle and crapemyrtle aphid. Whether these same insecticides might prove useful in the suppression of Japanese beetle on A. saccharum is yet to be determined. The most comprehensive study to date (Held, 2004) on susceptibility to Japanese beetle across a wide range of woody landscape plants noted that some species of Acer have demonstrated resistance to Japanese beetle. However, distinction of cultivar specific resistance for A. saccharum selections was not a part of the study (Held, 2004). Objectives The objectives of this research were to identify superior cultivars of Acer saccharum for landscape use in the Southeastern region of the United States, to evaluate growth and foliage characteristics of these cultivars, and to determine their tolerance to the Japanese Beetle. This research will help provide a basis for selecting sugar maple cultivars for nursery production and landscape use in the Southeast. Significance Expansion of the geographical market for sugar maple (Acer saccharum) into the Southeastern United States holds the potential of great financial profits for the landscape industry. The native range of sugar maple, which extends southward from Southern Canada and the Northeastern and North-central United States to as far south as 35 15 degrees north latitude (Flint, 1997), limits or excludes sugar maple production and sales in the major cities of the Southeastern United States. The identification of superior cultivars of A. saccharum for landscape use in the Southeast will enable growers to offer consumers in this region the opportunity to include one of the dominant trees of the deciduous forests of such states as New York, Vermont, West Virginia, and Wisconsin in southern landscapes (Calabrese, 1993). Height growth is an important indicator of overall health and viability of the selection, as well as an important consideration in tree placement within the landscape. Sugar maple is a large tree when mature and a suitable physical location must provide room for a large canopy of up to 60? and an eventual height of up to 100? (Dirr, 1998; Radford et al., 1968). Consumers desiring to purchase a tree that will provide shade relatively quickly will prefer selections that have faster growth rates. Census surveys show that the average tenure of residence for U.S. homeowners is only about 7 years (Schachter and Kuenzi, 2002). An ornamental landscape tree with a faster growth rate will likely be more appealing to many homeowners who want to plant sugar maple in their landscape but who will not likely be living in the same location when the tree reaches maturity. Their preference will be for faster growing selections that will provide shade in the summer and color in the fall in the shortest possible time. Caliper growth is important both as an indicator of overall health and viability of the selection, and because stronger trunk structures are more stable in windy conditions. Sugar maple use in areas where there is exposure to drying winds may be limited due to its sensitivity to desiccation (Cogliastro et al., 1997). Poor growth was observed for A. 16 saccharum when situated on an elevated rise with no windbreak, even though the site had moderately well drained soil thus preventing ?wet feet?. Leaf area is an important factor for the tree?s ability to photosynthesize. By exposing more leaf surface area to sunlight, larger leaves contribute to the tree?s ability to convert sunlight energy into usable chemical energy. The effect of wind on leaf size has also been documented (Niklas, 1996). Leaf characteristics have long been broadly used as diagnostic characters in the genus Acer (Desmarais, 1952). This very common and variable tree has attracted the attention of many taxonomists and since 1753 it has been described under not less than 17 specific, 18 varietal, and 18 formal names in more than 97 different combinations (Desmarais, 1952). Leaf area and petiole length also influence aesthetic differences among selections. The leaf itself is the character that shows the most striking variations and therefore is used most predominately as a reference point when describing the range, viability and distribution of Acer (Desmarais, 1952). While subjective, larger leaves and longer petioles could potentially offer aesthetically induced preference for one selection over another. Larger leaves contribute to canopy size, shape and fullness, as well as to fall color, thereby making selections with larger leaves preferable to those who consider these factors important. This preference, however, is nullified if the leaves are so large that they cause the tree to be more susceptible to wind damage because of canopy resistance to wind. Longer petioles contribute to the overall beauty of the tree canopy by placing the leaves further from the limb thereby allowing the leaves more freedom to move in light winds. Short petioles make the tree look stiff and less attractive. Therefore longer petioles 17 are desirable for aesthetic reasons. Cultivars like ?Autumn Blush?, which exhibit striking red petioles in the summer, take advantage of longer petioles, making the tree?s appearance more aesthetically appealing. The combination of colorful and longer petioles give ?Autumn Blush? a shimmering appearance that makes it commercially appealing for both homeowners and landscape professionals. Materials and Methods This field trial was initiated in March, 1999 at the North Alabama Horticultural Substation in Cullman, Ala. (USDA Cold Hardiness Zone 7, Latitude 34? 19? x Longitude 86? 8?) in a Hartsell Fine Sandy Loam soil. Trees were arranged in a completely randomized design on a 20 foot x 20 foot spacing. The 1999 installation included 13 sugar maple selections (?Astis? (Steeple?), ?Autumn Blush?, ?Bonfire? (Bonfire?), ?Commemoration?, ?Fairview? (Fairview?), ?Fall Fiesta? (Fall Fiesta?), ?Goldspire?, ?Green Mountain?, ?Legacy?, and ?Sweet Shadow Cut-Leaf?; and three sugar maple seedling selections (from A. McGill and Sons Nurseries, Gervais, OR; Ellenburg Nursery, Baileyton, AL; and J. Frank Schmidt and Son Nurseries, Boring, OR). Five additional selections were added to the study in 2001 (?Autumn Faith?, ?Endowment?, ?Flax Mill Majesty?, ?Sugar Queen?, ?Moraine? (Wright Brothers?)), three additional selections were added in 2003 (?Barrett Cole? (Apollo?), ?Morton? (Crescendo?), ?Seneca Chief?) and one additional selection was added in 2006 (?Reba? (Belle Tower?)), to conclude with a total of 22 selections, with 19 of about 32 named cultivars and 3 seedling sources. All trees were fertilized with 59 g of nitrogen (N), 25 g of phosphorus (P), and 49 g of potassium (K) as 13N ? 5.6P 2 O 5 ? 10.8K 2 O (13-13-13) per 2.54 cm (1 inch) of diameter (caliper) at planting and in subsequent years in the winter 18 months prior to budbreak. Trees were irrigated at planting and on an as-needed basis. Maple tip borer and other insect pests, excepting Japanese Beetle, were controlled as needed with appropriate chemicals. Height and caliper were measured at planting and after each growing season in December at one foot above the soil line in a North:South transect (Table 1; Table 2). Leaf area was determined using a Transparent Belt Conveyor Accessory Leaf Area Meter, LI-COR Model LI-3050A (Li-COR Inc., Lincoln, Neb.). Ten fresh leaves were harvested at random from each tree in June, 2006. Leaves were transported in a cooler to a lab at Auburn University where total leaf area and petiole length from the base of the leaf to the end of the peduncle measurements were determined (Table 3). A single SPAD-502 Chlorophyll Meter (Minolta Camera Co., Ltd., Japan) was used to assess leaf greenness in June, 2006. Three measurements were taken on leaves for each of the 10 trees of each selection in an arbitrary and nondestructive manner while still attached to the tree (Table 3). Resistance to Japanese Beetle (Popillia japonica) was evaluated in July 2004, 2005 and 2006 based on a rating for each treatment with a 0 to 3 scale where 0 = 0 to 24% injury, 1 = 25 to 49% injury, 2 = 50 to 74% injury, and 3 = 75 to 100% injury. A visual inspection of Japanese Beetle damage was assessed subjectively because more objective measurements would have required further stress to the trees when obtaining physical samples. All 22 selections in the trial were ranked, with lower rankings indicating less predation or more resistance (Table 4). Statistical analysis was carried out as a one-way analysis of variance (ANOVA) using the GLM procedure of SAS (SAS Version 9.1, Cary NC), with multiple 19 comparisons made using the Waller-Duncan Test at P = 0.05. A summary variable, Rating Index, was calculated for each tree as the mean of the standardized values of the six variables of Height Increase, Caliper Increase, SPAD values, Leaf Area, Petiole Length, and Japanese Beetle Damage with the exception of ?Reba? (Belle Tower?) for which Height Increase and Caliper Increase were not included (Table 5). Values were standardized by subtracting the overall mean for the specific variable from the data value and dividing this difference by the standard deviation (square root of the mean squared error). Results and Discussion Final height measurements were taken in 2006 and compared to measurements taken in 1999. The Ellenburg southern seedlings had the tallest final height, however, ?Seneca Chief? had the singularly largest average height increase at 73.41 cm (28.9 in.) per year followed by Bonfire TM at an average height increase of 54.61 cm (21.5 in.) per year (Table 1). Other good height increase performers were the Ellenburg seedlings, the J. Frank Schmidt seedlings, Steeple TM , and ?Sweet Shadow Cut-Leaf? (Table 1), all with an average height increase of about 45.72 cm (18 in.) a year. Although these four selections had average height increases statistically similar with each other and to Bonfire TM , they were statistically dissimilar to ?Seneca Chief? and these four selections occupy a second tier with ?Seneca Chief? occupying the sole position on the first tier as the statistically unique selection with the best height increase performance. The least average height increase was with ?Barrett Cole? (Apollo TM ) with an average height increase of 14.22 cm (5.6 in.), and while different from other selections would not be 20 considered different than ?Endowment? at 21.34 cm (8.4 in.) per year and Crescendo TM at 21.84 cm (8.6 in.) of height growth per year (Table 1). Final caliper measurements were taken in 2006 and compared to measurements taken in 1999. The Ellenburg southern seedlings had both the largest final caliper measurement and the largest average caliper increase source at 1.35 cm (0.5 in.) annual increase during the course of the field study. Average caliper increase for ?Autumn Blush?, ?Commemoration?, Fairview TM , Fall Fiesta TM , ?Morton? (Crescendo?), and ?Seneca Chief? was statistically similar to that for Ellenburg Southern seedlings (Table 2). Cultivars ?Barrett Cole? (Apollo TM ) and ?Endowment?, had the smallest caliper increase at 0.64 cm (0.25 in.) and 0.66cm (0.26 in.), respectively. ?Sweet Shadow Cut-Leaf?, ?Autumn Faith?, Green Mountain R , and ?Reba? (Belle Tower?) had the highest chlorophyll content as determined by the SPAD-502 Leaf Greenness Meter (Table 3). While SPAD units are not standard across all species, comparisons can be made within a species. As such, ?Autumn Faith?, Green Mountain R , and ?Reba? (Belle Tower?), all with chlorophyll levels of about 39 were 40% greener than the Ellenburg seedlings, the least green trees in the study with relative chlorophyll levels of 27.8. ?Goldspire? and the A. McGill seedling selections had the largest mean leaf area, each at 110.9 cm 2 , and followed closely by Green Mountain R at 107.5 cm 2 (Table 3). Others that had statistically similar mean leaf areas to Green Mountain R were ?Autumn Faith?, ?Endowment?, and the J. Frank Schmidt seedlings. The smallest leaves were recorded for ?Commemoration? at 47.7 cm 2 , with ?Legacy? only slightly larger at 54.8 cm 2 . 21 The longest mean petiole length measured was for Green Mountain R at 13.1 cm (5.2 in.) (Table 3). Statistically similar petiole lengths were measured for ?Autumn Faith?, ?Autumn Blush?, Bonfire TM , ?Goldspire?, and the J. Frank Schmidt seedlings (Table 3). Although not different than ?Barrett Cole? (Apollo TM ), ?Commemoration?, ?Legacy?, ?Sweet Shadow Cut-Leaf?, and ?Moraine? (Wright Brothers?), ?Morton? (Crescendo?) had the shortest petioles at 6.7 cm (2.6 in.). Japanese Beetle predation was highly selective and cultivar-specific in our field study (Table 4). Some selections, like ?Green Mountain?, remained virtually untouched while other selections immediately adjacent, like the J. Frank Schmidt seedlings, were virtually stripped of their leaves. Neither ?Barrett Cole? (Apollo TM ), ?Autumn Blush? nor ?Reba? (Belle Tower TM ), suffered any visible damage from Japanese Beetle. Although several other cultivars/selections had statistically similar damage to ?Barrett Cole? (Apollo TM ), ?Autumn Blush? and ?Reba? (Belle Tower TM ), ?Sugar Queen? was the only other cultivar that had less than a 0.15 damage rating. ?Fairview? suffered the most damage from Japanese Beetles, with a 2.8 damage rating from a possible 3.0 (Table 4). ?Fairview? trees were almost completely stripped of all leaves, as were those of the slightly less damaged selection ?Seneca Chief?. ?Goldspire?, ?Commemoration?, and the A. McGill and J. Frank Schmidt seedlings were also very susceptible to Japanese Beetle in our study. Although ?Goldspire? had the favorable characteristic of large leaves, it also was one of the least resistant to damage from Japanese Beetle. This information would be very valuable to nursery suppliers as well as to consumers intent on purchasing a sugar maple tree for long-term use in their landscape. 22 A summary variable, Rating Index, was calculated for each tree as the mean of the standardized values of the six variables of Height Increase, Caliper Increase, SPAD values, Leaf Area, Petiole Length, and Japanese Beetle Damage, with the exception of ?Reba? (Belle Tower?) for which Height Increase and Caliper Increase were not included (Table 5). Using this Rating Index, the top five selections in our study were Green Mountain R , ?Reba? (Belle Tower?), ?Autumn Blush?, ?Sugar Queen? and ?Bonfire? (Bonfire?). The selections with the poorest performance in our study, to date, were ?Commemoration?, ?Morton? (Crescendo?), and ?Moraine? (Wright Brothers?). Green Mountain R introduced by Princeton Nurseries in 1964 (van Gelderen et al, 1994) has a long history in the nursery trade with reliable fall color and broadly pyramidal growth habit. ?Reba? (Belle Tower?) is a new release (2006) from J. Frank Schmidt & Son Nursery selected by Jeff Sibley that originated from a population in Pulaski, Tennessee. The parent tree is located in Mt. Hope, Ala. (USDA Hardiness Zone 7) and has a fastigate growth habit and yellow-gold fall color. ?Autumn Blush?, another cultivar selected by Jeff Sibley has not yet been released to the trade. The original tree was planted in Southeast Alabama on the Auburn University Campus in 1962 (USDA Hardiness Zone 8) and was noted to have orange-red fall color and a broader than tall growth habit. ?Sugar Queen? was introduced by John Holmlund Nursery in Boring, Oregon about 1995. ?Sugar Queen? has attractive foliage with the lobes curling downward to almost have a teardrop appearance. However, in our study ?Sugar Queen? has been prone to leaf scorch. ?Bonfire? (Bonfire?) was released by J. Frank Schmidt & Son Nursery in about 1965 (van Gelderen et al, 1994) and has performed well in a variety 23 of climatic conditions. Bonfire? has an upright form, is a vigorous grower and typically has orange-red fall color. Conclusions Many criteria are used to evaluate a tree?s landscape value. Sugar maples are among the more valued landscape trees throughout the United States due to fall color, crown shape, and relatively few disease or pest problems. However, most cultivars have been selected for traits other than stress and insect tolerance. For example, ?Sweet Shadow Cut-Leaf? has the most unusual leaf shape of any sugar maple in the marketplace. The species has also been noted to have larger leaves, typical of selections from more northern climes than those populations found in the southern part of the native range (Desmarais, 1952). In the future, one of the great concerns for homeowners will be pest tolerance. Determination of suitable sugar maple selections for the Southeast with regard to insect feeding preference in addition to growth and environmental response will provide valuable information for producers and the landscape industry. Further Research This study is the first to report on performance of sugar maples as a landscape tree in the Southeastern United States. The study offers the landscape industry additional data that will help producers and consumers make informed choices when choosing sugar maple selections for landscape applications in the Southeast. Still, further research needs to be done so that nurseries and homeowners can continue to make more informed landscape choices. Differences in fall coloration among specific cultivars can be a determining factor for cultivar selection in landscapes where sugar maple thrives. 24 Information on growth, pest resistance, viability, heat tolerance and required chilling to satisfy rest are additional criteria in need of evaluation in the Southeastern United States. Studies have shown sugar maple to have an obligate chilling requirement, and therefore the species typically will only have one flush of growth in a growing season (Wood and Hanover, 1981). Sugar maple has difficulty thriving in urban bricked walkways (Schwets and Brown, 2000). Although Acer saccharum survived for up to 25 years when planted in a brick walkway, the surviving trees had lower canopy densities, higher amounts of twig die-back, and smaller canopy widths compared to trees planted in turfed areas, which performed better and were able to maintain form and structure. Those planted in a bricked walkway were more open-canopied and ragged in appearance when compared to those grown in turfed areas (Schwets and Brown, 2000). Research to determine appropriate selections for these environments would be helpful. A buried-pot study of 2-year-old sugar maple seedlings conducted in the northeastern United States to test how liming influences growth and nutrient balances of this species showed a 37% larger growth than control seedlings when the treatments were incorporated into the soil (Burke and Raynal, 1998). However, seedlings that received surface lime treatments were 9% smaller than control seedlings. Seedlings for this study were planted on May 9 and were harvested on August 30 of the same year. There is little information on the long-term effects of liming for A. saccharum. Further study and clarification of these and other criteria will give nursery providers and consumers in the Southeastern United States more confidence that their incorporation of Acer saccharum in the southern landscape will result in long-term success and sustainable market growth for sugar maple outside its native growing range. 25 Literature Cited Ball, J. 2001. The savory sugar maple. Amer. Forests, Vol. 106, No. 4:45-46. Burke, M.K. and D.J. Raynal. 1998. Liming influences growth and nutrient balances in sugar maple (Acer saccharum) seedlings on an acidic forest soil. Environ. and Expt. Botany 39:105-116. Calabrese, D.M. 1993. A geography of state trees. Amer. Forests, Vol. 99, No. 2:35-37. Cogliastro, A., D. Gagnon, and A. Bouchard. 1997. Experimental determination of soil characteristics optimal for the growth of ten hardwoods planted on abandoned farmland. For. Ecol. and Manag. 96:49-63. Desmarais, Y. 1952. Dynamics of leaf variation in the sugar maples. Brittonia, Vol. 7, No. 5:347-387. Dirr, M.A. 1998. Manual of Woody Landscape Plants: Their Identification, Ornamental Characteristics, Culture, Propagation and Uses. Stipes Publishing, Champaign, IL. 53-57. Flint, H.L. 1997. Landscape plants for Eastern North America: Exclusive of Florida and the Immediate Gulf Coast. 2nd. Ed. John Wiley and Sons, Inc., New York, NY. 27-28. Gu, M., J.A. Robbins, C.R. Rom, and J. McAfee. 2005. Japanese beetle (Popillia japonica Newman) feeding preference on birch taxa (Betula). HortScience 40:873. Held, D.W. 2004. Relative susceptibility of woody landscape plants to Japanese beetle (Coleoptera : Scarabaeidae). J. Arboric. 30:328-335. 26 Hogan, G.D. 1998. Effect of simulated acid rain on physiology, growth and foliar nutrient concentrations of sugar maple. Chemosphere, Vol. 36, No. 4-5:633-638. Laurence, J.A., R.J. Kohut, R.G. Amundson, D.A. Weinstein, and D.C. MacLean. 1996. Response of sugar maple to multiple year exposures to ozone and simulated acidic precipitation. Environ. Pollution, Vol. 92, No. 2:119-126. National Agricultural Pest Information System. 2003. Last accessed 6/1/2005. www.ceris.purdue.edu/napis/pests/jb/imap/jb2003.html. Niklas, K.J. 1996. Differences between Acer saccharum leaves from open and wind- protected sites. Annals of Bot. 78:61-66. Pettis, G.V., S.K. Braman, L.P. Guillebeau, and B. Sparks. 2005. Evaluation of insecticides for suppression of Japanese beetle, Popillia japonica Newman, and crapemyrtle aphid, Tinocallis kahawaluokalani Kirkaldy. J. Environ. Hort. 23:145-148. Radford, A.E., H.E. Ahles, and C.R. Bell. 1968. Manual of the Vascular Flora of the Carolinas. The University of North Carolina Press, Chapel Hill, NC. 686-688. Schachter, J.P. and J.J. Kuenzi. 2002. Seasonality of moves and the duration and tenure of residence: 1996. Population Division Working Paper Series No. 69. Population Division, U.S. Census Bureau, Wash. D.C. Schwets, T.L. and R.D. Brown. 2000. Form and structure of maple trees in urban environments. Landscape and Urban Planning 46:191-201. St. Hilaire, R. and W.R. Graves. 1999. Foliar traits of sugar maples and black maples near 43?N latitude in the eastern and central United States. J. Amer. Soc. Hort. Sci. 124:605-611. 27 Stafne, E.T., J.R. Clark, D.T. Johnson, and B.A. Lewis. 2005. Foliar damage of blackberries and blueberries by Japanese beetle (Popillia japonica). HortScience 40:879. Wood, B.W. and J.W. Hanover. 1981. Environmental control of sugar maple seedling growth. Research Report ? Michigan State Univ. Agric. Expt. Stat., Jan. 1981:1-10. van Gelderen, D.M., P.C. de Jong, and H.J. Oterdoom. 1994. Maples of the World. Pages 327-330. Timber Press, Portland, OR. Yang, S., X. Liu and M.T. Tyree. 1998. A model of stomatal conductance in sugar maple (Acer saccharum Marsh.). J. Theor. Biol. 191:197-211. Zhang, L., B.P. Oswald, and T.H. Green. 1999. Relationships between overstory species and community classification of the Sipsey Wilderness, Alabama. For. Ecol. and Manag. 114:377-383. 28 Table 1. Final height and average annual height increase for sugar maple selections in a North Alabama field trial. Z Selection Final Height Average Height Increase A. McGill Seedling 189.00 cde Y 16.71 de Autumn Faith 118.67 i 11.73 ghi Autumn Blush 193.22 bcd 17.32 cde Barrett Cole (Apollo TM ) 52.89 k 5.63 j Bonfire TM 210.25 ab 21.46 b Commemoration 179.38 cdef 15.34 defg Ellenburg Southern Seedling 216.56 a 20.65 bc Endowment 90.00 j 8.40 ij Fairview TM 188.90 cde 16.70 de Fall Fiesta TM 180.00 cdef 17.14 cde Flax Mill Majesty 132.00 hi 14.40 efgh Goldspire 172.50 def 16.07 def Green Mountain R 175.44 def 14.78 efg J. Frank Schmidt Seedling 184.70 cde 17.81 bcde Legacy 160.30 fg 12.61 fgh Morton (Crescendo TM ) 61.70 k 8.57 ij Seneca Chief 146.78 gh 28.93 a Steeple TM 198.25 abc 18.04 bcde Sugar Queen 147.57 gh 17.51 cde Sweet Shadow Cut-Leaf 169.17 ef 19.02 bcd Wright Brothers 113.44 i 10.69 hi Z Planting of accessions began in March 1999 with growth measured in inches annually in December. Y Values within columns followed by the same letter are considered different based on mean separation by Waller-Duncan?s Multiple k ratio t-Test at 0.05. Table 2. Final caliper and average annual caliper increase for sugar maple selections in a North Alabama field trial. Z Final Selection Caliper Average Caliper Increase A. McGill Seedling 3.00 def Y 0.36 bcdefghi Autumn Faith 1.83 hi 0.29 fghi Autumn Blush 3.39 bcd 0.42 abc Barrett Cole (Apollo TM ) 1.08 J 0.25 i Bonfire TM 3.30 cde 0.37 bcdefgh Commemoration 3.72 bc 0.46 ab Ellenburg Southern Seedling 4.20 a 0.53 a Endowment 1.70 hi 0.26 hi Fairview TM 3.27 cde 0.40 bcdefg Fall Fiesta TM 3.81 ab 0.42 abcd Flax Mill Majesty 2.04 h 0.33 cdefghi Goldspire 2.64 F 0.30 defghi Green Mountain R 3.24 de 0.40 bcdef J. Frank Schmidt Seedling 2.85 ef 0.33 cdefghi Legacy 3.21 de 0.40 bcdef Morton (Crescendo TM ) 1.43 ij 0.41 abcde Seneca Chief 1.66 hi 0.42 abc Steeple TM 3.30 cde 0.37 bcdefghi Sugar Queen 2.11 gh 0.34 cdefghi Sweet Shadow Cut-Leaf 2.55 fg 0.30 efghi Wright Brothers 1.80 hi 0.28 ghi Z Planting of accessions began in March, 1999 with growth measured in inches annually in December. 29 Y Values within columns followed by the same letter are considered different based on mean separation by Waller-Duncan?s Multiple k ratio t-Test at 0.05. 30 Table 3. Chlorophyll content, mean leaf area and mean petiole length for sugar maple selections in a North Alabama field trial. Z Selection Chlorophyll content (SPAD) Mean Leaf Area (cm 2 ) Mean Petiole Length (cm) A. McGill Seedling 28.0 gh Y 110.85 a 10.8 bcde Astis (Steeple TM ) 29.3 fgh 82.35 cdefg 9.6 def Autumn Faith 39.4 a 92.67 bcd 11.2 abcd Autumn Blush 31.8 cdef 90.67 cde 12.1 ab Bailsta (Fall Fiesta TM ) 32.0 bcdef 87.29 cdef 10.0 cdef Barrett Cole (Apollo TM ) 34.5 bc 71.70 ghij 8.2 fghij Bonfire TM 32.8 bcde 65.73 hijk 11.7 abc Commemoration 31.2 defg 47.70 l 7.3 ghij Ellenburg Southern Seedling 27.8 h 89.80 cde 9.5 def Endowment 31.2 defg 94.29 bc 9.3 defg Fairview TM 30.5 defgh 78.00 defghij 9.6 def Flax Mill Majesty 31.2 defg 77.10 efghij 10.2 bcdef Goldspire 31.0 defgh 110.89 a 12.1 ab Green Mountain R 38.5 a 107.53 ab 13.1 a J. Frank Schmidt Seedling 29.9 efgh 93.02 bcd 11.2 abcd Legacy 33.7 bcd 54.78 kl 6.9 ij Morton (Crescendo TM ) 33.6 bcd 63.40 k 6.7 j Reba (Belle Tower TM ) 38.4 a 79.94 cdefghi 8.8 efghi Seneca Chief 29.9 efgh 65.20 ijk 9.0 efgh Sugar Queen 32.5 bcdef 81.46 cdefg 10.3 bcdefg Sweet Shadow Cut-Leaf 35.1 b 80.38 cdefgh 7.0 hij Wright Brothers 29.7 efgh 72.64 fghi 8.1 fghij Z Planting of accessions began in March 1999 with measurements taken in June and July 2006. Y Values within columns followed by the same letter are considered different based on mean separation by Waller-Duncan?s Multiple k ratio t-Test at 0.05. 31 Table 4. Japanese beetle feeding preference among sugar maple selections in a North Alabama field trial. Z Selection Damage Rating Y Rank X Barrett Cole (Apollo TM ) 0.00 a 1 Autumn Blush 0.00 a 1 Reba (Belle Tower TM ) 0.00 a 1 Sugar Queen 0.14 ab 2 Legacy 0.30 abc 3 Autumn Faith 0.40 abc 3 Bonfire (Bonfire TM ) 0.50 abcd 4 Ellenburg, Southern Seedling 0.70 abcd 4 Astis (Steeple TM ) 0.75 bcd 5 Bailsta (Fall Fiesta TM ) 0.78 bcd 5 Green Mountain (Green Mountain R ) 0.80 bcde 6 Sweet Shadow Cut-Leaf 0.80 bcde 6 Morton (Crescendo TM ) 0.90 cde 7 Endowment 1.00 cde 7 Flax Mill Majesty 1.14 def 8 Wright Brothers (formerly 'Moraine') 1.14 def 8 Goldspire 1.50 efg 9 A. McGill Seedling 1.78 fg 10 Commemoration 1.88 g 11 J. Frank Schmidt Seedling 1.90 gh 12 Seneca Chief 2.60 hi 13 Fairview (Fairview TM ) 2.80 i 14 Z Evaluations made in July 2004, 2005 and 2006 in a sugar maple field trial in Cullman, Alabama (USDA Hardiness Zone 7) planted from 1998 to 2006. Data presented is from 2004. Y Rating determined on a 0 to 3 scale where 0 = 0 to 24% injury, 1 = 25 to 49% injury, 2 = 50 to 74% injury, and 3 = 75 to 100% injury. Rating followed by mean separation by Waller-Duncan?s Multiple k ratio t-Test at 0.05. X All 22 selections in the trial were ranked, where 1 is least damaged and 14 is most damaged tree. 32 Table 5. Growth and quality summary rating index for sugar maple field trial in Cullman, Alabama (USDA Hardiness Zone 7) planted from 1998 to 2006. Z Selection Average Rating Index Y Order X Green Mountain (Green Mountain R ) 0.800 a 1 Reba (Belle Tower TM ) 0.692 ab 2 Autumn Blush 0.654 abc 3 Sugar Queen 0.404 abcd 4 Bonfire (Bonfire TM ) 0.354 abcde 5 Ellenburg, Southern Seedling 0.313 bcde 6 Autumn Faith 0.246 bcdef 7 Bailsta (Fall Fiesta TM ) 0.228 cdef 8 Goldspire 0.191 def 9 Sweet Shadow Cut-Leaf 0.095 defg 10 Seneca Chief 0.058 defg 11 Astis (Steeple TM ) 0.002 defgh 12 A. McGill Seedling -0.048 efghi 13 J. Frank Schmidt Seedling -0.078 efghij 14 Endowment -0.162 fghij 15 Flax Mill Majesty -0.201 fghij 16 Legacy -0.289 ghijk 17 Barrett Cole (Apollo TM ) -0.433 hijk 18 Fairview (Fairview TM ) -0.446 ijk 19 Wright Brothers (formerly 'Moraine') -0.480 ijk 20 Morton (Crescendo TM ) -0.509 jk 21 Commemoration -0.671 k 22 Z Rating index was calculated for each tree as the mean of the standardized values of the six variables of Height Increase, Caliper Increase, SPAD values, Leaf Area, Petiole Length, and Japanese Beetle Damage with the exception of ?Reba? (Belle Tower?) for which Height and Caliper were not included. Values were standardized by subtracting the overall mean for the specific variable from the data value and dividing this difference by the standard deviation (USDA Hardiness Zone 7) planted from 1998 to 2006. Y Average Rating Index where values followed by the same letter are considered different based on mean separation by Waller-Duncan?s Multiple k ratio t-Test at 0.05. X All 22 selections in the trial were ranked in order as most suitable to least suitable.