Can forest management based on natural disturbances maintain ecological resilience?

Given the increasingly global stresses on forests, many ecologists argue that managers must maintain ecological resilience: the capacity of ecosystems to absorb disturbances without undergoing fundamental change. In this review we ask: Can the emerging paradigm of natural-disturbance-based management (NDBM) maintain ecological resilience in managed forests? Applying resilience theory requires careful articulation of the ecosystem state under consideration, the disturbances and stresses that affect the persistence of possible alternative states, and the spatial and temporal scales of management relevance. Implementing NDBM while maintaining resilience means recognizing that (i) biodiversity is important for long-term ecosystem persistence, (ii) natural disturbances play a critical role as a generator of structural and compositional heterogeneity at multiple scales, and (iii) traditional management tends to produce forests more homogeneous than those disturbed naturally and increases the likelihood of unexpected catastrophic change by constraining variation of key environmental processes. NDBM may maintain resilience if silvicultural strategies retain the structures and processes that perpetuate desired states while reducing those that enhance resilience of undesirable states. Such strategies require an understanding of harvesting impacts on slow ecosystem processes, such as seed-bank or nutrient dynamics, which in the long term can lead to ecological surprises by altering the forest's capacity to reorganize after disturbance

Contrôles démographiques de la biomasse forestière aérienne en Amérique du Nord

International audienceEcologists have limited understanding of how geographic variation in forest carbon arises from differences in growth and mortality at continental to global scales. Using forest inventory data from across North America, we partitioned continental-scale variation in biomass growth and mortality rates of 49 tree species groups into (1) species-independent spatial effects and (2) inherent differences in demographic performance among species groups. 82% and 51% of the respective variation in growth and mortality was explained by spatial factors that were independent of species-group composition. Moderate additional variation in mortality (26%) was related to species-group turnover across the continent. Biomass accumulation models showed that variation in forest biomass can be explained primarily by spatial gradients in growth that were unrelated to species-group composition. Species-dependent patterns of mortality explained additional variation in biomass, with forests supporting less biomass when dominated by species groups that are highly susceptible to competition or to biotic disturbances

Consistent land- and atmosphere-based U.S. carbon sink estimates

International audienc