Environmental Effects On The Growth Of Young Longleaf Pine

Abstract

A study to determine the effects of environmental conditions on the growth of young longleaf pine (Pinus palustris Mill) was initiated in 1969 on the Escambia Experimental Forest near Brewton, Alabama. Forty young longleaf trees initially ranging from 1 to 1.5 meters in height were measured from 1969 through 1981. The trees were evenly divided between two soil types. From 1969 to 1970, height and diameter measurements were recorded once to four times weekly during the growing seasons and once a month during the dormant seasons. Daily height growth measurements were recorded in the morning and again in the evening during the peaks of these two growing seasons to determine diurnal and nocturnal growth. To test the effects shading on growth, cheesecloth was suspended over ten randomly selected trees from each soil type during the first growing season. Follow up height and diameter measurements were recorded periodically from 1971 through 1981. All environmental conditions were recorded by weather station instruments located on the site. The shading treatment did not have a significant effect on either height or diameter growth. Soil type did have a significant effect on diameter growth. Dormant season temperature and precipitation explained more of the variability in yearly height and diameter growth than any other environmental conditions measured. Height growth during the peak of the growing season accounted for more than 30% of yearly height growth. Temperature was the most influential environmental variable affecting height growth during the peak of the growing season.