PROCEEDINGS: Index of Abstracts
GROWTH RESPONSES OF WHITE OAK AND BLACK OAK TO DROUGHT
STRESS ACROSS GRADIENTS OF ACID DEPOSITION AND MICROCLIMATE
1-Dept. of Biology, Ball State University, Muncie,
IN 47306. 2-USDA Forest Service, North Central Forest Experiment
Station, E. Lansing, MI 48823.
Based on data from Illinois, Indiana, and Ohio following the 1988
drought, acid deposition does not increase the susceptibility of
oak trees to drought stress. Measurements at six sites along a gradient
from comparatively high to low levels of acid deposition refuted
the hypothesis that high acid deposition rates would predispose
oaks to growth decline and mortality after a severe drought. Neither
patterns of growth rate nor outbreak of two-lined chestnut borer
correlate with acid deposition patterns. Differences in growth and
mortality between sites appear to relate to differences in the timing
and duration of drought conditions.