Dynamic modeling of the spatial and temporal variations of forest carbon and nitrogen inventories, including their responses to hurricane disturbances, in the Luquillo Mountains, Puerto Rico

I used an ecosystem modeling approach in this dissertation research to examine the spatial and temporal variability in gross primary production (GPP), net primary production (NPP), and storages and fluxes of soil organic carbon (SOC) and nitrogen in the Luquillo Experimental Forest (LEF) of Puerto Rico. I focused this work on the response and recovery of these forest properties to hurricanes, specifically Hurricane Hugo on 18 September 1989. Analyses based on simulation results and comparison between simulations and observations from field studies demonstrated that forest productivity and soil carbon and nitrogen pools and fluxes respond to elevational and topographic gradients (ridges, slopes, benches, and valleys) over the entire Luquillo Mountains. The large spatial heterogeneity of the forest properties studied in the LEF is the result of heterogeneous distribution of solar insolation, temperature, soil moisture and other physical environmental factors, and the interaction between abiotic and biotic factors across the landscape of the Luquillo Mountains. Disturbances of large scale and varying intensity, such as hurricanes, enhance the heterogeneity of forest production and soil carbon and nitrogen distribution in this tropical forest. The basic model results were well validated although simulated hurricane-induced changes in forest productivity and storage and fluxes of soil carbon and nitrogen in the LEF could not be validated yet by field measurements.