An evaluation of the hardwood regeneration model (REGEN) 16 years post-harvest of a regenerated stand in East TennesseeThis article is part of a larger document. View the larger document here.
The REGEN model (developed by USDA Forest Service, Southern Research Station, Bent Creek Experimental Forest) was used prior to harvest to predict species composition of hardwoods at crown closure. This study evaluates whether the predictive ability of the model was effective by using post-harvest information after 16 years. Regeneration data were collected prior to harvest in February through April 1997 at the University of Tennessee Forest Resources Research and Education Center near Oak Ridge, TN. Five site preparation treatments were implemented to favor desired species and to control undesired species in the future stand: preharvest slash only, preharvest slash with herbicide stump treatment, post-harvest slash only, post-harvest slash and herbicide stump treatment, and control (no slashing or herbicide). Each set of five treatments was replicated six times for a total of 30 treatment plots (0.33 acre per treatment plot). Predictions of overstory composition and number from the REGEN model (using the Southern Appalachian variant) by site preparation treatment are compared to the actual stand data after 16 years to determine the accuracy and utility of the model in forecasting species composition at crown closure prior to harvest. Results indicate that the REGEN model performed well in predicting species composition at crown closure. The model overcompensated for presence of yellow-poplar (Liriodendron tulipifera L.), enough to provide reasonable estimations of the number of overstory stems after 16 years. Pre- or post-harvest site preparation techniques had little effect on presence of light-seeded species such as yellow-poplar and black cherry (Prunus serotina Ehrh.). About 10 percent of total overstory stems after 16 years were oaks (Quercus spp.), regardless of site preparation treatment. The same percentage of advanced oak seedlings was represented in the pre-harvest regeneration inventory