Overview of Experiments

Overview of Model Experiments

The major results of this work follow from four experiments performed on the model. In each case, we present the visualizations from these experiments to aid in understanding the large-scale model behavior.

Implementing clear-cuts:: We simulated harvesting with three different one-time clear-cuts that differ in the spatial scale of the cuts and the survival of seedlings. We use this model experiment to explore the effects of harvesting adult trees and the role of surviving seedlings in natural regeneration. The clear-cuts are contrasted with the base-line runs in which disturbances are absent or are smaller and occur frequently.

The role of individual-tree mortality:: We simulated a stressed forest with increased risk of mortality for all trees. In the base-line simulations, adult trees experience a low risk of mortality independent of species, age, and vigor. We increase this threat of random mortality across all trees. The increased individual mortality is contrasted with the disturbed-forest base-line runs in which groups of neighboring trees are destroyed.

The role of spatial interactions:: We assess the role of spatially localized interactions in controlling forest development by removing these localized interactions from a series of simulations. Both undisturbed and disturbed "spaceless" simulations are contrasted with their base-line counterparts.

Finding simpler descriptions of species:: We attempt to simplify the parameter set used to describe the nine species used in SORTIE. A multivariate statistical technique (principal components analysis) is used to find a two-parameter metric describing species life history. This simplification is presented and then simulations based on this are contrasted with their base-line counterparts.