Collaborative Research: Forest Dynamics in Heterogeneous Landscapes

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Throughout much of the past three hundred years the settlement of New England has resulted in the destruction and fragmentation of native forest vegetation. Recently, there has been an increase in forest regeneration in this region. This study is designed to gather field data from a variety of sites that will be used to parameterize a model of forest development based on actual starting conditions measured in the field. Forest dynamics is a function of seed dispersal, seedling establishment, and differential growth rates of component species. In this study field experiments will be conducted in a range of forest habitats to determine the role of seed dispersal and herbivory in effecting forest regeneration. The results from these experiments will be used to adjust and improve the forest dynamics model called SORTIE. Models such as SORTIE provide baseline data under known conditions against which it will be possible to compare actual patterns of forest regeneration. The mechanisms associated with the model will dramatically increase our ability to predict changes in forest vegetation. The ability to predict changes will have important implications for global climate change and its effects on future biodiversity. %%% Previous approaches to modelling forest dynamics have relied exclusively on average response variables and average environmental conditions. The SORTIE model represents a vast improvement over earlier models because it is truly spatially explicit. Initial conditions will be derived from positions of individual trees and saplings measured in the field. In addition, the actual environmental conditions in different stands will be measured and incorporated into the model. The role of herbivores in forest regeneration is being measured and added to the model. Finally, this model represents an advance because it incorporates environmental heterogeneity.