PARENT SESSION
Poster Session # 14: Forest Ecology.
Wednesday, August 6 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Canopy area, growth, and fecundity in a mixed-hardwood forest.
Wolosin, Michael*,1, Clark, James1, LaDeau, Shannon1, Dietze, Michael1, 1 Duke University, Durham, NC
ABSTRACT- Forest simulators predict community dynamics based on models of species-specific growth, fecundity, and mortality rates that vary with tree size. In most, neighbors interact only through exploitative competition for light. While several field studies have examined the changes in growth and mortality rates with resource availability for seedlings and saplings, the demographic responses and trophic trade-offs of larger trees are less well known. These relationships are explored using a combination of remote sensing and field data from four hectares of mixed pine-hardwood forest in the North Carolina Piedmont. High-resolution aerial videography and subsequent three-dimensional canopy reconstructions provide measurements of height and exposed canopy area (ECA) of individual trees at a level of detail impossible from the ground. Additional field measurements of total canopy area (TCA), diameter at breast height (dbh), and dbh growth have been made for each tree over 20 cm dbh of several hardwood species, including Acer rubrum,, Carya spp., Liquidambar styraciflua, Liriodendron tulipifera, and Quercus alba. Seed trap data collected over three years and inverse modeling of dispersal provide fecundity estimates of individual trees. Regression analyses are used to estimate allometries between canopy measurements, height, and diameter for each species. Initial results show that the relationship between canopy area (a measure of light availability and hence photosynthesis) and growth and fecundity do vary between species, providing evidence that large trees do experience trade-offs. Canopy area is generally more predictive of growth at lower values. The difference between observed canopy area for an individual and the predicted canopy area based on dbh and height allometries provides an index of tree vigor; the ability of this index to predict individual level growth and fecundity is explored.
Key words: growth, canopy area, aerial imagery