Collaborative Research: Climate-Fire-Ecosystem Linkages On Decadal-to-Centennial Time Scales in the Northern Rockies

这个为期三年的多学科合作研究项目重建了爱达荷州北部和蒙大拿州西部塞尔韦-比特鲁特荒野地区2000多年来亚高山森林的火灾、植被和气候历史。其目的是在不同的时间和空间尺度上研究气候、火情和植被组成之间的联系。气候、火灾和植被的变化和相互作用塑造了景观。相互作用的过程根据分析的时间和空间尺度而变化。在世纪到千年的时间尺度和景观到区域的空间尺度上，气候的大变化决定了火灾状态和植被组成。在这些总体尺度上，火和植被之间的联系还不太清楚。在年-年代际尺度和流域空间尺度上，火灾的频率、大小和严重程度由气候/天气、植被和着火频率决定。在这些更精细的尺度上，火灾和植被之间的联系相当发达：植被决定了燃料的可用性，火灾创造了一种塑造植被恢复的景观模式。调查人员将从湖泊沉积物中的木炭和花粉数据、树木年轮记录和树木年龄信息中获得过去火灾频率的信息。他们将根据历史火灾地图校准湖泊沉积物和树木年轮记录，以估计火灾的空间范围。数据将在流域、景观和区域尺度上进行汇编。他们将根据每个流域过去300多年的白松和落叶松年轮宽度年表进行气候重建。这些重建应该使我们了解火灾的年代学和引起史前火灾的天气性气候条件。在美国西部，20世纪晚期的火灾制度是否反映了气候的变化，是人类活动的产物，还是当前的管理实践，是科学和公共政策辩论的主题。这项研究应该提供有关火灾历史、植被和气候的数据，并朝着理解这些因素之间相互作用的时空特定过程的方向发展。

SBR-9715961 Whitlock University of Oregon This three-year, collaborative, multi-disciplinary research project reconstructs the fire, vegetation, and climate history of the sub-alpine forests of the Selway-Bitterroot Wilderness Area in northern Idaho and western Montana over 2,000 years. Its purpose is to examine the linkages among climate, fire regimes, and vegetation composition at different temporal and spatial scales. The variation in and interaction of climate, fire, and vegetation shape the landscape. The processes of interaction vary according to the temporal and spatial scale of analysis. At century-to-millennial temporal scales and at landscape-to-regional spatial scales, large changes in climate determine fire regime and vegetation composition. The linkages between fire and vegetation at these gross scales is less clear. At annual-to-decadal temporal scales and at the watershed spatial scale, fire frequency, size, and severity are determined by climate/weather, vegetation, and ignition frequency. In these finer scales, the linkages between fire and vegetation are fairly well developed: vegetation determines fuel availability, and fires create a landscape pattern that shapes vegetation recovery. Investigators will derive information on the frequency of past fires from charcoal and pollen data in lake sediments, tree-ring records, and tree-stand age information. They will calibrate the lake-sediment and tree-ring records against historical fire maps, to estimate the spatial extent of fires. The data will be compiled at the watershed, landscape, and regional scales. They will develop climate reconstructions from Pinus albicaulis and Larix lyalli tree-ring-width chronologies for the last 300+ years in each watershed. These reconstructions should yield an understanding of fire chronology and synoptic climatic conditions giving rise to prehistoric fires. In the western United States, whether late-twentieth-century fire regimes reflect a shift in climate, a product of human activity, or current management practices is a topic of scientific and public-policy debate. This research should provide data on fire history, vegetation, and climate, and move toward understanding the temporally and spatially specific processes of interaction among these elements.