Postdisturbance recovery of aboveground biomass and nutrients in tropical temperate, and boreal forests
A number of issues in basic and applied forest ecology require an understanding of the controls on post-disturbance regrowth that result in variable rates of biomass accumulation. In this study, aboveground biomass data was compiled from chronosequence and long-term studies of secondary forests worldwide to model aboveground biomass accumulation (ABA) in forests following stand-clearing disturbances.
Regression analyses and tests for slope homogeneity indicate that soil texture influenced the ABA of broadleaf forests; broadleaf stands underlain by sandy soils exhibited slower GSDY-adjusted ABA than broadleaf stands growing on non-sandy soils. On non-sandy soils, the GSDY-adjusted ABA of tropical and non-tropical broadleaf forests was indistinguishable; as a group, tropical forests are not particularly slow to recover aboveground biomass following disturbance events. Differences in soil texture were less important for needle-leaf forests; on the whole, the GSDY-adjusted ABA of needle-leaf forests was intermediate between that of sandy and non-sandy broad-leaved forests.
The global model of forest ABA was tested by calculating rates of ABA for forests recovering from slash-and—burn cultivation on two Amazonian sites—sandy dystrophic upland (terra firme) and non-sandy eutrophic floodplain (várzea). As predicted by the global model, non-sandy várzea forests accumulated more biomass and at a faster rate than sandy terra firme forests.
Disturbance characteristics (e.g., size, severity, and frequency) may also influence ABA. The global model of ABA included only regrowth following stand-clearing disturbances. The model was applied to broadleaf and coniferous temperate montane rainforests in southern Chile to test its applicability to regrowth following less severe, patchy disturbances. ABA following gap-disturbance was highly variable, although most plots fell within the range of biomass predicted by the global model.