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Changes in Structure, Pattern and Diversity Associated with Climax Forest Maturation in Piedmont, North Carolina
Norman L. Christensen
The American Midland Naturalist
Vol. 97, No. 1 (Jan., 1977), pp. 176-188
Published by: The University of Notre Dame
Stable URL: http://www.jstor.org/stable/2424693
Page Count: 13
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During 1951 and 1952 the position and diameter were recorded for each tree on a 140 x 140 m plot of immature climax oakhickory forest in the Duke Forest, Durham, North Carolina. To ascertain the changes in structure associated with climax forest maturation, this plot was remapped in 1974 and the two maps compared. In general, tree density, particularly of overstory trees, decreased while total basal area increased from 1951-52 to 1974. The most notable changes were a 75% reduction in density of Carya spp. and a 230% increase in density of Acer rubrum. Many dominant species showed significant reduction of numbers in smaller size classes in 1974. Tree-by-tree analysis of mortality and recruitment revealed low rates of population recruitment and high mortality rates in these smaller size classes. Tree pattern, analyzed by quadrat and point-to-neighbor methods, was clumped in smaller size classes and random or regular in larger size classes on both maps. However, total tree pattern shifted from random in 1951-52 to regular in 1974. This shift was the result of significantly higher mortality in the smaller size classes which had clumped distributions. Species diversity, H', decreased during this time; however, pattern diversity (Pielou, 1966) increased. Decreased species diversity resulted from diminished equitability, whereas increased pattern diversity was probably due to shifts in tree pattern.
The American Midland Naturalist © 1977 The University of Notre Dame