Despite the rising popularity of alternative forestry practices such as partial harvests, little research has focused on modeling forest development under alternative silviculture. Information on growth and yield of partially harvested stands is critical for their evaluation both in terms of their capacity to provide habitat and to produce timber. In previous work, we documented large residual-tree growth responses and elevated rates of post-harvest tree mortality. Based on our results, we developed spatially explicit growth and mortality behaviors and incorporated them into an individual-based forest simulator model (SORTIE-ND) to explore stand dynamic responses to a range of partial harvest treatments in the black spruce boreal forest of Ontario, Canada.

Results/Conclusions

Over the first decade after harvest, stand development proceeded most rapidly following high retention treatments and low skidding intensity scenarios, where residual-tree mortality was reduced. Growth rates of individual residual trees increased with partial harvest intensity, a result of reduced competition levels. Residual-tree responses had a strong influence on long-term growth and yield predictions. Across treatments with equivalent retention levels, estimated basal area return intervals were up to 30 years shorter for scenarios in which skidding intensity and neighbourhood competition were reduced. Results from these simulations provide essential information for assessing the viability partial harvest treatments in the boreal forest. Further, they indicate that considering residual-tree growth and mortality responses is critical for accurate forecasting of stand dynamics following moderate-severity disturbances such as partial harvests, insect outbreaks, and wind storms.