Holocene Fire-Climate-Vegetation Linkages in the Western Mid-latitude Forests of North and South America

该奖项将帮助研究人员了解北美和南美西部中纬度森林的气候，植被和火灾动态的相互作用。这两个地区提供了重要的比较，在他们目前的气候，植被，火灾制度和他们的环境历史。这两个地区的植被类型不同，但气候历史大致相似。不同的气候历史源于对全新世大尺度气候强迫机制的不同反应（即，夏季日照变化）。这项研究将发挥每个地区的相似性和差异性，以提供一套自然的实验，不可能在一个单一的地区。这一点很重要，因为气候、火灾和植被是北美西部和南美森林生态系统中密切相关的组成部分。这些组成部分之间联系的强度和性质因所涉时间尺度而异。在年内时间尺度上，天气条件通过影响特定季节内的燃料湿度和点火源来确定火灾事件的可能性。在年际到十年的时间尺度上，气候变率是重要的，因为潮湿和干燥期的顺序间接促进火灾的发生。年际和年代际尺度上的植被变化也通过确定可燃物的性质和分布来影响火灾活动。火灾事件，反过来，形状森林演替，并创建景观格局，为随后的干扰事件。在百年到千年的时间尺度上，气候控制着火灾频率、规模和严重程度以及植被组成和物种分布的长期变化。长时间尺度上的植被特征也通过确定燃料生物量的性质对火灾状况产生正反馈。这项研究将在北美西部和巴塔哥尼亚开发一个可与现有植被历史网络相媲美的高分辨率火灾历史网络，辨别促进或抑制火灾的气候控制等级，并检查现代气候数据，以确定影响研究区域火灾状况的大规模气候异常。通过建立火灾历史数据库和分析过去和现在与火灾相关的气候异常，研究人员将能够在多个尺度上了解气候-火灾-植被之间的联系。研究人员将通过共享数据库（包括国家地球物理数据中心）和出版物与更大的科学界分享他们的数据。此外，研究人员将与南美同事建立强有力的合作，以实现北美和南美研究人员之间的技术转让。这将部分通过支持外国科学家前往美国分享数据和分析技术来实现。

This award will help researchers understand the interplay of climate, vegetation, and fire dynamics in the mid-latitude forests of western North and South America. The two regions offer important comparisons in terms of their present climate, vegetation, and fire regime and their environmental history. Both regions feature different vegetation types but broadly similar climate histories. The varying climate histories arise from distinct responses to large-scale climate forcing mechanisms in the Holocene (i.e., variations in summer insolation). This research will play each region's similarities and differences against each other to provide a set of natural experiments not possible in a single region. This is important because climate, fire, and vegetation are closely related components of forest ecosystems in western North and South America. The strength and nature of the linkages among these components vary depending on the time scale of interest. On intra-annual time scales, weather conditions determine the likelihood of fire events by influencing fuel moisture and ignition sources within a given season. On inter-annual to decadal time scales, climate variability is important because the sequence of wet and dry periods indirectly promotes fire occurrence. Vegetation changes on inter-annual and decadal scales also affect fire activity by determining the character and distribution of fuels. Fire events, in turn, shape forest succession and create landscape patterns that set the stage for subsequent disturbance events. On centennial-to-millennial time scales, climate governs the long-term variations in fire frequency, size, and severity as well as vegetation composition and species distributions. Vegetation characteristics on long time scales also exert a positive feedback to fire regimes by determining the nature of the fuel biomass.This research will develop a high-resolution fire-history network in western North America and Patagonia comparable to existing vegetation-history networks, discern the hierarchy of climate controls that either promote or suppress fire, and examine modern climate data to determine the large-scale climate anomalies that influence fire regimes in the study areas. This approach of developing a fire-history database and analyzing climate anomalies associated with fire at present and in the past, will allow the researchers to understand climate-fire-vegetation linkages on multiple scales.The researchers will share their data with the larger scientific community through shared databases (including the National Geophysical Data Center) and publications. In addition, the researchers will forge strong collaboration with South American colleagues to enable technology transfer between North and South American researchers. This will be accomplished, in part, through the support of foreign scientist's travel to the United States to share data and analytical techniques.