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

Sbr-9715961俄勒冈州惠特洛克大学的这项为期三年的、合作的、多学科的研究项目重建了爱达荷州北部和蒙大拿州西部塞尔韦-比特罗特荒野地区亚高山森林超过2000年的火灾、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、火势和植被组成之间的联系。气候、火和植被的变化和相互作用塑造了景观。相互作用的过程因分析的时间和空间尺度而异。在百年到千年的时间尺度和从景观到区域的空间尺度上，气候的巨大变化决定了火灾制度和植被组成。在这些总尺度上，火和植被之间的联系不太清楚。在年到十年的时间尺度和分水岭空间尺度上，火灾的频率、大小和严重程度由气候/天气、植被和点火频率决定。在这些更精细的尺度上，火和植被之间的联系发展得相当好：植被决定燃料的可获得性，而火创造了一种影响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、树木年轮记录和林木年龄信息中获得有关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。这些数据将在流域、景观和区域尺度上进行汇编。他们将根据每个流域过去300多年的白皮松和落叶松年轮宽度年表重建气候。这些重建应该对引起史前火灾的火灾年表和天气气候条件有所了解。在美国西部，二十世纪末的火灾制度是否反映了气候的变化，是人类活动的产物，还是目前的管理做法，是科学和公共政策辩论的主题。这项研究应该提供关于火灾历史、植被和气候的数据，并朝着了解这些元素之间在时间和空间上特定的相互作用过程的方向发展。

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.