Alternative Design and Analysis - Maximum Sustainable Sawtimber Production

An interesting, and often used, contrast to the Custodial Alternative is the Maximum Sustainable Sawtimber Production Alternative. Under this alternative, Goal G-3 is favored and allowed to dominate all other goals. This means that goals that are compatible with goal G-3 will probably also improve their satisfaction rating. Those goals in conflict with goal G-3 will be negatively impacted.

We used a Southern Appalachian Hardwood Forest Regeneration Simulation Model to forecast stand composition and size following a regeneration harvest. The USDA Forest Services Forest Vegetation Simulation System (FVS) was used for growth and mortality prediction of existing stands. FVS was also used to simulate various types and intensities of thinnings over the 40-year projection period. The NED DSS was again used to compare the resulting simulated forest with the goal hierarchy. We assumed no financial constraints.

To design this alternative, we need to understand what we have to do in order to improve quality sawtimber production at Bent Creek. By reviewing the current condition analysis, we realize that we have to create a better distribution of size classes. This implies regeneration harvesting. Beyond that, we need to make sure each stand is well stocked, not understocked and not overstocked. Stocking control is usually achieved by thinnings of various kinds. We also need to favor the high-value species whenever possible. We can discover which species are high value by looking at the species encyclopedia in NED. Releasing high-value species from competition also implies thinning prescriptions.

After examining the current conditions and the custodial alternative, we identified several types of stands where active management will move Bent Creek closer to the goal of sustained sawtimber production. First, there are many stands in the small sawtimber size class that become too dense if left alone for 40 years to grow and where the proportion of basal area in high value species declines in favor of less valuable commercial tree species. By thinning these stands from below we can keep the stand within the density range best for sawtimber production. By favoring the high value species while we are thinning and removing their immediate competitors, we can increase their proportionate basal area. Next, there are stands in the large and small sawtimber size classes with lower than optimum stand density. These stands become prime candidates for regeneration.

The maximum sustainable sawtimber alternative appeared to improve goal accomplishment dramatically (BROKEN-LINK BROKEN-LINK Table). Both goals G-1 (Large Scale Variety) and G-2 (Local Biological Diversity) became fully satisfied as we aggressively achieved a more balanced size-class distribution of stands in the management unit. Goal G-3 (Sawtimber Production) improved to minimally satisfied because 40 years was not enough time to repopulate the small sawtimber size class from stands growing out of the sapling and pole size classes. At the stand level, we can see that the thinning prescriptions were effective in reducing the number of stands in the "Not Satisfied" category from 78% in the current condition to only 20% under this alternative. Goal G-4 (Limit Peak Flow) has still not been satisfied because there are still no evergreen trees in the riparian zone stands. As expected, Goal G-5 (Black Bear) changed from "Minimally Satisfied" to "Not Satisfied." Recall that DFC-1 for Black Bear required greater than 30% of the stands to meet stand level DFCs. Although regenerating stands also provide enough coarse woody debris to pass DFC-2, these stands grow into the sapling and pole size classes after only 10 years. The transient nature of the regenerating stands and the reduction in large sawtimber stands contribute to the degradation of Black Bear habitat under this scenario.