Tamm Review: Management of mixed-severity fire regime forests in Oregon, Washington, and Northern California

摘要: Abstract Increasingly, objectives for forests with moderate- or mixed-severity fire regimes are to restore successionally diverse landscapes that resistant and resilient current future stressors. Maintaining native species characteristic processes requires this successional diversity, but methods achieve it poorly explained in the literature. In Inland Pacific US, large, old, early seral trees were a key historical feature of many young old forest patches, especially where fires frequently occurred. Large, naturally fire-tolerant, today often threatened by dense understory cohorts create fuel ladders alter likely post-fire pathways. Reducing these understories can contribute resistance creating conditions canopy will survive disturbances climatic stressors; survivors important seed sources, soil protectors, critical habitat elements. Historical timber harvesting has skewed tree size age class distributions, created hard edges, altered patch sizes. Manipulating promote development larger patches older, larger, more widely-spaced increase landscape severe fires, enhance wildlife underrepresented conditions. Closed-canopy, multi-layered develop hot, dry summer environments vulnerable droughts, they vulnerability insect outbreaks wildfires. These same provide such as northern spotted owl, which benefited from increased area. Regional local planning be gauging risks, evaluating trade-offs, restoring dynamics support other species. The goal manage heterogeneous include variably-sized (1) young, middle-aged, closed-canopy growing upper montane, northerly aspect, valley bottom settings, (2) similar diversity open-canopy, fire-tolerant on ridgetops, southerly aspects, lower montane (3) significant chaparral grassland areas. Tools managed wildfire, prescribed burning, variable density thinning at small large scales. Specifics “how much where?” vary according physiographic, topographic templates, regulatory requirements, determined means socio-ecological process.