Have Altered Fire Regimes Reduced Forest Resilience to Climate Change?

火灾制度的改变是否降低了森林对气候变化的适应能力？

• 批准号: RGPIN-2014-06387
• 负责人: Daniels, Lori
• 金额: $ 2.48万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=631981
• 关键词: Altered; Fire; Regimes; Reduced; Forest

Wildfire is a key driver of forest dynamics. Changes to fire regimes triggered by subtle changes in climate and land use have potential major impacts on forests. The current rate and magnitude of climate change have the potential to exceed historical and evolutionary limits, jeopardizing ecological resilience so that ecosystems are unable to recover from disturbance. Thus, understanding fire regimes drivers is essential to anticipate potential consequences of climate change and develop effective adaptation and mitigation strategies to enhance forest resilience. My research has shown that mixed-severity fire regimes historically dominated in many montane cordilleran forests in British Columbia (BC) and the foothills of Alberta. In these forests, regional climate interacts with local controls by topography and human land use, resulting in complex fire regimes that can be difficult to quantify. These ecosystems appear particularly susceptible to rapid change due to the combined effects of climate change and fire exclusion. Improved understanding of the dynamics and drivers of mixed-severity fire regimes is urgently needed to assure the resilience of these forests. My long-term research program addresses this knowledge gap. Over the next 5 years my graduate students and I will complete a series of inter-related research projects designed to meet 3 short-term objectives: 1. To compare fire histories among regions in the montane cordilleran ecozone and determine if changes to fire regimes in the 20th century are pervasive 2. To quantify the relative importance of the mechanisms driving fire-regimes and their interactions3. To initiate new research on the consequences of altered fire regimes on fuel hazards and forest resistance to crown fire – two indicators of resilience in mixed-severity fire regimes.The first phase of this research is a comparative analysis of fire histories in four distinct climatic regions in the montane cordilleran forests of western Canada: Rocky Mountains, Kootenays, Okanagan and Cariboo. We will use multiple lines of evidence to compare fire history among these study areas. This approach will enable us to determine if changes to historic fire regimes are pervasive among climatic regions and along elevation gradients.The second research phase investigates climate as a driver of fire regimes. We will compile modern fire and weather records for 1991-2010 to interpret the range of fire weather conditions associated with lightning-caused ignitions in the dry montane forests in BC. For a longer-term perspective, we will use our multi-century fire-scar records to test for widespread fire years within and among regions. We will compare our fire records with proxy-climate data to test for the influence of climatic variation and historic fire occurrence.Finally, we will quantify the consequences of 20th century fire exclusion on dry montane forests in BC. Fieldwork will quantify the degree to which forest composition, structure and fuels have changed in absence of surface fires. Fire behavior models will be used to simulate changes to fuel loads, climate and their interaction, ultimately testing their effects on forest resistance to crown fires. Four PhD, 3 MSc and at least 10 undergraduate students will be integrally involved with this research. Our research on fire regime drivers will help to (1) anticipate future fire regimes under the influence of climate change, (2) identify segments of the landscape where resilience has been reduced by fire exclusion, and (3) establish priorities and targets to guide ecological restoration and fuels mitigation implemented by the BC Ecological Restoration Program, Parks Canada and the Canadian Wildlife Service.

野火是森林动态的关键驱动因素。气候和土地利用的微妙变化引发的火灾状况的变化可能对森林产生重大影响，目前气候变化的速度和程度有可能超过历史和进化的极限，危及生态恢复力。因此，了解火灾状况的驱动因素对于预测气候变化的潜在后果并制定有效的适应和缓解战略以增强森林的恢复能力至关重要。许多山区不列颠哥伦比亚省（BC）的科迪勒拉森林和阿尔伯塔省的山麓地区，区域气候与地形和人类土地利用的当地控制相互作用，导致难以量化的复杂火灾状况。这些生态系统似乎特别容易受到快速火灾的影响。迫切需要更好地了解混合严重程度的火灾的动态和驱动因素，以确保这些森林的恢复能力。未来5年我的我和研究生将完成一系列相互关联的研究项目，旨在实现 3 个短期目标： 1. 比较山地山脉生态区各地区的火灾历史，并确定 20 世纪火灾状况的变化是否普遍存在 2量化驱动火灾机制及其相互作用的相对重要性3 启动关于改变火灾机制对燃料危害和森林对树冠火灾的抵抗力的影响的新研究——这两个指标是混合严重程度火灾的恢复力指标。这项研究的第一阶段是对加拿大西部山地山脉森林的四个不同气候地区的火灾历史进行比较分析：落基山脉、库特尼、奥肯那根和卡里布。我们将使用多种证据来比较不同地区的火灾历史。这种方法将使我们能够确定历史火灾状况的变化是否在气候区域和海拔梯度上普遍存在。第二个研究阶段将调查气候作为火灾状况的驱动因素。编制 1991 年至 2010 年的现代火灾和天气记录，以解释与 BC 省干燥山地森林中闪电引起的火灾相关的火灾天气条件范围。从长远来看，我们将使用我们的多世纪火灾疤痕记录。测试内部和之间广泛的火灾区域。我们将把我们的火灾记录与代理气候数据进行比较，以测试气候变化和历史火灾发生的影响。最后，我们将量化 20 日的后果。对不列颠哥伦比亚省干燥山地森林的世纪火灾排除工作将量化在没有地表火灾的情况下森林组成、结构和燃料的变化程度，最终将使用火灾行为模型来模拟燃料负荷、气候及其相互作用的变化。测试它们对森林抵御树冠火灾的影响。四名博士生、三名硕士生和至少 10 名本科生将全面参与这项研究，我们对火灾动态驱动因素的研究将有助于 (1) 预测气候影响下的未来火灾动态。改变，（2）识别(3) 制定优先事项和目标，以指导不列颠哥伦比亚省生态恢复计划、加拿​​大公园管理局和加拿大野生动物管理局实施的生态恢复和燃料缓解措施。