Fire-regime complacency and sensitivity to centennial- through millennial-scale climate change in Rocky Mountain subalpine forests, Colorado, U.S.A.

1. Key uncertainties in anticipating future fire regimes are their sensitivity to climate change, and the degree to which climate will impact fire regimes directly, through increasing the probability of fire, versus indirectly, through changes in vegetation and landscape flammability. 2. We studied the sensitivity of subalpine forest fire regimes (i.e., fire frequency, fire severity) to previously documented climate variability over the past 6000 years, utilizing pollen and macroscopic charcoal from high-resolution lake-sediment records in Rocky Mountain National Park, Colorado. We combined data from the four lakes to provide composite records of vegetation and fire history within a 200 km2 study area. 3. Rates of forest burning were relatively complacent to millennial-scale summer cooling and decreased effective moisture. Mean return intervals between fire episodes, defined over 500-year periods, generally varied between 150-250 years, consistent with tree-ring-based estimates spanning...

1. 预测未来火灾格局（fire regimes）的核心不确定性，在于其对气候变化的敏感性，以及气候通过两种路径影响火灾格局的程度：一是直接提升火灾发生概率，二是间接通过改变植被与景观可燃性实现影响。
2. 本研究以美国科罗拉多州落基山国家公园内高分辨率湖相沉积记录中的孢粉与宏观炭屑为研究材料，探究了过去6000年间亚高山森林火灾格局（即火灾频率、火灾强度）对已记录气候变率的敏感性。我们整合了四个湖泊的沉积数据，以构建200平方公里研究区域内的植被与火灾历史综合记录。
3. 森林火烧速率对千年尺度的夏季降温与有效湿度降低的响应相对平缓；以500年时段为界定的火灾事件平均重现间隔，大致在150至250年之间波动，这与基于树轮的估算结果一致，该估算覆盖了...