Baldwin, Jr., V. C., P. M. Dougherty, and H. E. Burkhart. 1998. A
Linked Model for Simulating Stand Development and Growth Processes of
Loblolly Pine. Chpt. 17, pp.305-325 In: R. A. Mickler and S. Fox (eds.). The Productivity and Sustainability of Southern Forest Ecosystems in a
Changing Environment. Springer, New York. 892p.
Simulations, using a linked model system comprised of a growth and
yield model (PTAEDA2) and a physiological model
(MAESTRO), are performed
to quantify the effects of changing tree and stand structure over time
on tree ecophysiology. This objective is accomplished in two steps. First,
the effects of changes in stand structure during plantation growth,
including thinning, on individual tree form are predicted using
PTAEDA2
for high and low site index lands. Finally, the effects of these
tree structural changes on some tree physiological processes are
evaluated. This analysis shows that age, site index, and thinning affect
many crown features including total leaf area per tree, mean crown
leaf area density, leaf area density distribution, crown length, and
the nonfoliated fraction of the crown volume. These features are
important for predicting tree physiological functioning. Although some
canopy changes have only minor effects on net carbon gain,
collectively the effect on light interception may be substantial. The
simulations also clearly indicate that large differences in woody
tissue maintenance respiration are likely to result when respiration
is expressed on a woody surface area basis rather than as a function
of woody biomass. Overall, it is shown that as a research tool, the
linked PTAEDA2-MAESTRO
system allows one to evaluate the effects of
small changes in stand structure on physiological processes that could
not be predicted with physiological modeling alone.