LANDSCAPE FOREST MODELING OF THE LUQUILLO EXPERIMENTAL FOREST (LEF), PUERTO RICO

An important objective of the LEF LTER program is to understand the dynamics of forest community response to environmental gradients and disturbances over the entire mountain landscape. We describe a combined gap and patch-transition modeling approach to contribute to this objective. A gap model (FACET) was parameterized for species of various forest types (Tabonuco, Colorado, Dwarf and Palm). Climate and soil data were processed for input to FACET; soil types were derived from Geographic Information Systems (GIS) operations on soil mapping units and slope. Several FACET extensions and modifications were developed to reflect LEF conditions: PET was increased, an excess soil-moisture index and corresponding species response were developed, and hurricane effects were incorporated. Hurricane effects were based on frequency, intensity factors, location damage risk class, and species susceptibility. FACET was run over many terrain conditions (combinations of slope, elevation, aspect, soils and hurricane risk class) and compared to existing data. To develop the MOSAIC patch-transition landscape model, forest cover types were defined by dominance of species of each forest type and canopy height. MOSAIC parameters were calculated from runs of FACET for multiple terrain conditions. MOSAIC runs were then analyzed for distribution patterns. GIS was used to process terrain variables, hurricane risk and MOSAIC model output.