PROCEEDINGS: Index of Abstracts

EVALUATION OF METHODOLOGY FOR DETECTING/PREDICTING MIGRATION OF FOREST SPECIES

Dale S. Solomon and William B. Leak

Research Foresters, USDA Forest Service, Northeastern Forest Experiment Station, Durham, NH 03824.

Available methods for analyzing migration of forest species are evaluated, including simulation models, remeasured plots, resurveys, pollen/vegetation analysis, and age/distance trends. Simulation models have provided some of the most drastic estimates of species changes due to predicted changes in global climate. However, these models require additional testing against field data to ensure their reliability. Remeasured plots would provide a basis for model testing, but the number of plots required to detect short term trends might be excessive. Remeasurement data from forested areas where there have been no land-use changes provide a clearer picture of migrational trends. A 60-year record from the Bartlett Forest provided estimates of species changes in relation to management versus no management, land type, and elevation. Migration rates based on historical pollen analyses are of limited value because these analyses are derived from small, scattered samples formed under physical/biological conditions much different from those of today. Age/distance trends from carefully chosen and specified study locations will provide estimates of recent migrational trends and rates of elevational change. Independent surveys of vegetation in areas where previous plots cannot be relocated are subject to the same limitations as remeasured plots.