PRODUCING GROWTH ESTIMATES OF DUKE FOREST PINE STANDS USING USDA’S FOREST VEGETATION SIMULATOR

Duke Forest manages its loblolly pine stands for timber revenues. Duke Forest seeks construct a management plan informed by an optimized harvest schedule. This project aims to produce a reliable growth and yield model in order to produce the volume yield estimates necessary to compute the optimized harvest schedule. This was accomplished by testing and calibrating USDA’s Forest Vegetation Simulator (FVS) using Duke Forest Continuous Forest Inventory data. FVS was tested by using different site index inputs, and the diameter growth modifiers of FVS were then applied to reproduce current loblolly pine stand characteristics. It was found that the observed site index of a Duke Forest loblolly pine stand produces a better estimate of Duke Forest basal areas than do the Natural Resource Conservation Service’s Web Soil Survey site indices. Despite the use of the more accurate site index numbers, FVS needed further calibration in order to produce statistically significant estimates of Duke Forest basal areas. Diameter growth modifiers of 1.25, 2.6, and 2.6 were applied to stands with low, average, and high site indices respectively, which calibrated the model. FVS, when calibrated, can provide Duke Forest with a workable growth and yield model. In the future, even more precise calibrations will be possible as the continuous Forest Inventory process continues, and plots sampled for this project are re-sampled. This will inform the diameter and height growth increments FVS uses to grow the inputted trees into the future.