Fire-Driven Forest Transitions in Response to Land-Use Impacts and Moisture Availability

该研究项目将调查不断变化的环境条件，燃料类型和丰度的变化以及野火改变森林生态系统中的森林模式和再生动态的复杂方式。 该项目将提供关于环境变异性和土地使用做法如何影响极端火灾事件概率的新见解，并将更好地了解生态过程和与人类有关的因素，这些因素是森林植被迅速向非森林植被转变的原因。 该项目有可能改进森林复原力的建模，促进对影响森林火灾发生因素的科学认识，并为资源管理界提供宝贵的支持。 调查人员将与森林和国家公园管理人员互动，以解决极端野火事件发生率增加所造成的土地管理挑战。 该项目将为科学、技术工程和数学开辟新的途径，并为本科生和研究生提供研究经验，包括来自代表性不足的少数群体的学生。全球野火活动的增加正在导致世界许多地区从森林植被类型向非森林植被类型转变。 这些变化对森林产品的未来供应和其他森林利益具有重要影响。 了解野火发生的地点和时间以及野火如何改变随后野火的可能性，对于理解生态系统状态的长期火灾驱动变化至关重要。 这项研究将解决两个基本的地理问题：（1）是什么条件和机制，开始从森林转移到更容易发生火灾的植被类型？ (2)是什么因素和机制倾向于支持更容易发生火灾的植被继续占主导地位，并阻碍树木再生？ 该项目将在夏季干旱的温带森林生态系统中进行，该区域被广泛认为是对环境因素和土地使用做法造成的森林覆盖率长期变化和森林崩溃高度敏感的区域。 研究人员将把火灾和植被变化的大规模空间建模与小气候和树木再生的密集、精细规模的实地测量和分析性实地实验相结合。 该项目的研究结果将提供对全球土地利用实践和生态过程的新认识，这些实践和生态过程与极端火灾事件的发生率增加有关，这些事件导致森林植被迅速向非森林植被转变。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This research project will investigate the complex ways in which changing environmental conditions, changes in types and abundance of fuels, and wildfires have altered forest patterns and regeneration dynamics in forest ecosystems. This project will offer new insights regarding how environmental variability and land-use practices affect the probability of extreme fire events, and it will provide a better understanding of the ecological processes and human-related factors that are responsible for rapid shifts from forest to non-forest vegetation. The project has the potential to improve modeling of forest resilience, advance scientific understanding of factors affecting the occurrence of forest fires, and provide valuable support to the resource-management community. The investigators will interact with forest and national park managers to address land management challenges caused by increased occurrence of extreme wildfire events. The project will open new pathways into science, technology engineering, and mathematics and provide research experiences for undergraduate and graduate students, including students from underrepresented minority groups.The global increase in wildfire activity is causing shifts from forest to non-forest vegetation types in many regions of the world. These changes have important implications for future supplies of forest products and other forest benefits. Knowledge of where and when wildfire occurs and how wildfire alters the potential for subsequent wildfires is critical for understanding the long-lasting, fire driven shifts in ecosystem states. The research will address two basic geographic questions: (1) What are the conditions and mechanisms that initiate shifts from forests to more fire-prone vegetation types? (2) What are the factors and mechanisms that tend to favor continued dominance of the more fire-prone vegetation and impede tree regeneration? The project will be conducted in a summer-dry, temperate forest ecosystem that is widely recognized as a region that is highly sensitive to long-lasting shifts in forest covers and forest collapse driven by environmental factors and land-use practices. The investigators will integrate broad-scale spatial modeling of fire and vegetation changes with intensive, fine-scale field measurements and analytical field experiments of microclimate and tree regeneration. Findings from this project will provide new understandings about global land-use practices and ecological processes relevant to increased occurrence of extreme fire events that factor in rapid shifts from forest to non-forest vegetation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.