Effects of thinning-induced changes in structural heterogeneity on growth, ingrowth, and mortality in secondary coastal Douglas-fir forests

摘要: Thinning is believed to accelerate the development of late-successional attributes, thereby enhancing stand structural heterogeneity in young, secondary forests. By making use a large-scale experiment implemented 40- 60-year-old coastal Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) forests, we addressed following objectives: (i) determine effect three thinning treatments on temporal dynamics (first 11 years after thinning) key forest structure measures, (ii) evaluate relationships between spatially explicit diversity measures and nonexplicit metrics, (iii) test observed periodic volume growth, ingrowth, mortality. Treatments consisted high-density, moderate-density, variable-density thinnings-from-below, as well control. Differences were mostly nonsignificant. However, our results suggest that stands displayed enrichment tree size species increased throughout study period result continuous ingrowth other than Douglas-fir. Simple metrics could not be used reliably model measures. The inclusion only rarely improved accuracy sample plot level mortality prediction models. Despite short-term nature this study, conclude shows promise increasing young even-aged stands. growth models may beneficial, but further work needed clarify underlying relationships, particularly at individual-tree level.