Evaluating Forest Vegetation Simulator Predictions for Southern Appalachian Upland Hardwoods with a Modified Mortality Model
Abstract:Prediction accuracy for projected basal area and trees per acre was assessed for the growth and yield model of the Forest Vegetation Simulator Southern Variant (FVS-Sn). Data for comparison with FVS-Sn predictions were compiled from a collection of n = 1,780 permanent inventory plots from mixed-species upland hardwood forests in the Southern Appalachian Mountains. Over a 5-year projection interval, baseline FVS-Sn predictions fell within 15% of observed values in over 88% of the test plots. Several modifications to FVS-Sn were pursued, including a refitting of the background mortality equation by logistic regression. Following the modifications, FVS-Sn accuracy statistics increased to 91 and 94% for basal area and trees per acre, respectively. In plots with high initial stand densities, notable gains in accuracy were achieved by relaxing thresholds that activated a density-dependent mortality algorithm in FVS-Sn. Detailed accuracy results for forest types of the region were generated. Twenty-five-year projection results show size-density trajectories consistent with the concept of maximum stand density index.
Document Type: Research Article
Publication date: May 1, 2012
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- Each regional journal of applied forestry focuses on research, practice, and techniques targeted to foresters and allied professionals in specific regions of the United States and Canada. The Southern Journal of Applied Forestry covers an area from Virginia and Kentucky south to as far west as Oklahoma and east Texas.
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