Doctoral Dissertation Research: Spatial Resilience in Forests Recovering from Fires

这位博士生将研究景观水平的过程如何支持被严重烧毁的森林的再生和恢复能力。具体地说，这项研究将集中在幸存的树木与景观相互作用的方式，为烧毁地区的恢复提供外部种子来源。最近的研究只使用有限的直线距离到最近的树木种子源，这没有充分考虑规模、格局或与局部地点的相互作用，以进行区域恢复。因此，在理解烧毁地区的周围环境如何支持或降低其恢复潜力(空间复原力)方面，存在着知识差距。项目成果将有助于开发更好地考虑到世界上野火变得更加严重和频繁发生的景观背景的方法。鉴于这些变化，土地管理者必须做出决定，在野火活动后，哪些被烧毁的地区需要积极地重新种植，哪些地区表现出更高的自然空间弹性。根据烧毁地区在景观中的位置确定其优先顺序，这可能是这一决策的基础。为协助决策，研究结果将作为决策树产品分发给当地和区域森林管理人员。此外，该项目将为本科生提供教育机会，让他们参与实地工作，并开发讲习班，让K-12女孩参与地理和空间科学。最后，该项目将支持一名女博士生，进一步扩大妇女和代表性不足的群体在地理和空间科学领域的参与。确定景观背景对被烧毁森林的恢复具有重要意义的空间尺度，是全面了解森林复原力和恢复的重要第一步。然而，尺度依赖效应往往是物种特有的，因此确定相关尺度必须考虑不同的树木特征以及与当地立地对树木生长的适宜性的相互作用。为此，这位博士生提出了三个研究问题：(1)景观背景的空间范围和格局如何支持烧毁地区的恢复？(2)景观背景如何与恢复地区的当地立地特征相互作用？(3)在更广泛的时间和空间范围内，景观背景是否会在更干燥、更容易发生火灾的景观中调节森林生态系统服务的弹性？这些问题将使用统计建模和来自大黄石生态系统自然实验的现场调查数据来回答。自然实验景观包括在类似地球物理环境中代表烧伤模式和火灾后气候条件的梯度的火灾，从而提供了一个独特的机会来观察景观环境对不同烧伤地区恢复的影响。此外，研究人员将使用空间上明确的生态系统过程模型来调查更广泛的时间和空间尺度上的景观背景如何支持碳储存和树木生物多样性。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The doctoral student will investigate how landscape-level processes support forest regeneration and resilience in forests that were severely burned. Specifically, the research will focus on the ways in which surviving trees interact with the landscape to provide external seed sources for a burned area's recovery. Recent studies used only a limited measurement of straight-line distance to nearest tree seed source, which does not fully consider scale, pattern, or interactions with local site suitability for area recovery. Consequently, there is a knowledge gap regarding an understanding of how a burned area's surrounding context in the landscape supports or reduces its recovery potential (spatial resilience). Project findings will contribute to the development of approaches that better account for landscape context in a world where wildfires are becoming more severe and occurring more frequently. Given these changes, land managers must make decisions about which burned areas need to be actively replanted following wildfire activity versus areas that exhibit higher natural spatial resilience. Prioritizing burned areas in the context of their position in the landscape could be fundamental to this decision-making. To aid with decision-making, research findings will be disseminated as a decision-tree product to local and regional forest managers. Furthermore, the project will provide educational opportunities for undergraduate students by involving them in fieldwork and by developing workshops that engage K-12 girls with geography and spatial sciences. Finally, the project will support a female doctoral student, further broadening participation of women and underrepresented groups in geography and spatial sciences.Identifying the spatial scales at which landscape context is important for a burned forest's recovery is an important first-step in a holistic understanding of forest resilience and recovery. However, scale-dependent effects are often species-specific, thus identifying relevant scales must account for divergent tree traits and interactions with local site suitability for tree growth. To do so, the doctoral student asks three research questions: (1) What spatial extents and patterns of landscape context support a burned area's recovery? (2) How does landscape context interact with local site characteristics of recovering areas? (3) At broader temporal and spatial extents, will landscape context mediate resilience of forest ecosystem services in drier, more fire prone landscapes? These questions will be answered using statistical modeling and fieldwork-generated data from a natural experiment in the Greater Yellowstone Ecosystem. The natural experimental landscape includes fires that represent a gradient of burn patterns and post-fire climate conditions in a similar geophysical setting, thereby providing a unique opportunity to observe the effects of landscape context on different burned areas' recovery. Additionally, the investigator will use a spatially explicit ecosystem process model to investigate how landscape context at broader temporal and spatial scales support carbon storage and tree biodiversity.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.