ibclogo XVI International Botanical Congess


Abstract Number: 5986
Poster No. = 1514


GROWTH OF CANOPY TREE SAPLINGS WITH RESPECT TO SOIL PH.


Seth Bigelow and Charles Canham. Institute of Ecosystem Studies, Box AB, Millbrook New York USA.


Canopy tree species in upland transitional oak-maple-hemlock forest in NW Connecticut, USA are sorted along soil pH gradients. To determine the cause we selected a total of 1100 saplings from the six dominant species and measured soil pH, light availability, and recent twig extension growth for each one. Soil pH mirrored that commonly found for adult trees: highest values were associated with ash (x = 5.01) and sugar maple (x = 4.75) whereas lower values (3.95 ( x ( 4.36) were found for red maple, beech, red oak, and hemlock. Surprisingly, twig extension at a given light level did not differ according to pH for sugar maple, beech, red oak, and hemlock, and was highest at the low end of the pH range over which red maple and ash occurred. These findings suggest that sorting along pH gradients has already occurred by the sapling stage, and that sorting in most species is not mediated by pH effects on growth.


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