Lundquist J E
USDA Forest Service, Rocky Mountain Research Station, 240 West Prospect Rd., Fort Collins, CO, USA 80526.
Plant Dis. 2007 Feb;91(2):147-152. doi: 10.1094/PDIS-91-2-0147.
Disturbances that kill trees in forests often co-occur in time and/or space. This process results in changes in the fuel loading for wildfire. Determining specific causes of changing fuel loads can be complex. Path analysis was used to estimate the relative importance and the strength of interaction of each of nine small-scale disturbances affecting forest stands in the Black Hills. Different disturbances were partitioned according to their indirect and direct effects on fuel loads. Fire and wind had the greatest indirect effects; stem rots had the smallest. Root rots had the largest direct effects. Root rots, strong wind, stem rots, suppression, human disturbances, and tree cutting all caused fuel loads to increase. Treeless meadows, stem cankers, fire, ice/snow damage, failed regeneration, and shallow soil were associated with decreasing fuel loads. Grazing, lightning, bark beetles, and competition had null impacts. Disease control has two aims: reducing fire hazard and enhancing restoration. Understanding the biology and ecology of the agents that create dead wood is as fundamental to restoration ecology as it is to forest pathology. Management and control both begin by first determining the cause.
森林中导致树木死亡的干扰因素常常在时间和/或空间上同时发生。这一过程会导致野火燃料载量的变化。确定燃料载量变化的具体原因可能很复杂。路径分析被用于估计影响黑山森林林分的九种小规模干扰因素各自的相对重要性及其相互作用的强度。不同的干扰因素根据其对燃料载量的间接和直接影响进行了划分。火灾和风的间接影响最大；茎腐病的间接影响最小。根腐病的直接影响最大。根腐病、强风、茎腐病、郁闭、人为干扰和树木砍伐都会导致燃料载量增加。无树草地、茎溃疡病、火灾、冰雪损害、更新失败和土壤浅薄与燃料载量减少有关。放牧、雷击、树皮甲虫和竞争没有影响。疾病防治有两个目标：降低火灾风险和促进恢复。了解造成枯木的因素的生物学和生态学对于恢复生态学和森林病理学同样至关重要。管理和控制都首先从确定原因开始。
