PARENT SESSION
Poster Session # 14: Forest Ecology.
Wednesday, August 6 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Characterizing successional volumetric patterns of canopy architecture.
Weishampel, John*,1, Parker, Geoffrey2, 1 Department of Biology, Orlando, FL, USA2 Smithsonian Environmental Research Center, Edgewater, MD, USA
ABSTRACT- Structurally, a forest canopy is analogous to a fractal sponge--a volume of spaces and phytomass between two (as found with a planar object) and three (as found with a solid object) dimensions. The spatial organization of canopy components (i.e., leaves, twigs, branches, etc.) directly influences the biotic habitat (e.g., light, temperature, humidity) and hence, atmospheric exchange, and tree growth and physiology. To measure canopy architectural dynamics associated with forest succession, data were collected using a handheld laser instrument to measure zenith-projected surfaces in four (30 x 30 x 40 m) forest stands. These stands represent different successional stages of the "tulip poplar" association, a mixed deciduous forest type found in eastern Maryland, USA. Its climax stage typically possesses an overstory dominated by Liriodendron tulipifera. This chronosequence, representing young, intermediate, mature, and old-growth stands, has been characterized vertically as having: a compressed monomodal canopy, an expanded monomodal canopy, a bimodal leaf distribution, and an uneven leaf area distribution, respectively. Using three-dimensional textural analysis techniques coupled with neutral modeling, we explored the lacunarity and multifractal patterns of the morphological elements and spaces that comprise these volumes as determined by the laser measuring system. This neutral modeling approach is a derivative of percolation theory, which is commonly used by landscape ecologists for depicting patterns and processes between one and two dimensions. Here, it is applied to provide a basic interpretation and discrimination of these complex, hierarchical structures.
Key words: Eastern deciduous forest, succession, canopy architecture, fractal