Doctoral Dissertation Research: Using Neutral Models to Evaluate the Effect of Topography on Landscape Patterns of Fire Severity: A Case Study of Lassen Volcanic National Park

火灾已成为一个越来越重要的干扰，以了解由于最近的火灾规模和严重性的增加，沿着越来越多的人居住在农村地区。在不同的景观中，火灾严重程度的空间变化的原因包括日常的天气条件，灭火和燃料积累，其他过去的管理措施和气候。林火强度斑块的位置可以是随机的，也可以是受地形影响而在空间上固定的。然而，量化的地形上观察到的模式的火灾严重补丁的影响是困难的，因为火灾是随机事件燃烧通过动态和异质燃料，天气和历史管理条件。中性模拟模型将允许本研究保持这些混杂因素不变，以评估地形对预测火灾强度的相互作用。本研究将解决以下问题，使用拉森火山国家公园作为案例研究：1）森林表面和冠层燃料的分布是什么，这些燃料是如何与底层的生物物理景观？2)对于在恒定天气条件下燃烧的均质燃料，地形对火灾强度的影响是什么？ 3)观察到的高强度火灾模式是否与假设的中性模式结果或使用绘制的地表和冠层燃料对真实的景观条件进行火灾模拟的结果相匹配？ 将在一个分类和回归树模型中结合实地测量、地形信息和遥感大地卫星数据绘制树冠燃料图，以预测整个地貌的树冠燃料负荷。一个中性模型的方法来火行为modeling将比较假设的景观与两个真实的景观和历史数据上的火灾严重程度，以评估地形控制的火灾强度的强度和这种新的approach.Results的有用性，这项研究将解决地形的作用，在创建异质性的植被群落结构和组成的景观，通过其对火灾强度的影响。此外，本研究将评估灭火对改变高强度火灾造成的斑块的景观位置的影响。某些类型的植被，特别是拉森火山国家公园，以及整个加州和美国西部的其他地方，需要高度严重的火灾，这些火灾已经被大力抑制。使用中性模型来评估高严重性火灾在景观上造成异质性的可能性，将有助于资源管理人员和消防队员在高度改变的森林中对野火、野火使用、规定的火灾和其他燃料处理做出更好的决策。作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立的研究生涯。

Fire has become an increasingly important disturbance to understand due to recent increases in fire size and severity, along with growing human habitation in rural areas. Causes of spatial variation in fire severity across landscapes include daily weather conditions, fire suppression and fuel build up, other past management action, and climate. Fire severity patch location could be stochastic, or fixed in space by topographic influences. However, quantifying the effect of topography on observed patterns of fire severity patches is difficult because fires are stochastic events burning through dynamic and heterogeneous fuel, weather, and historic management conditions. Neutral simulation models will allow this research to hold these confounding factors constant to assess the interaction of topography on predicted fire intensity. This research will address the following questions, using Lassen Volcanic National Park as a case study: 1) What is the distribution of forest surface and canopy fuels and how are those fuels related to the underlying biophysical landscape? 2) What is the effect of topography on fire intensity for a landscape of homogenous fuels burning under constant weather conditions? 3) Do observed patterns of high intensity fire match either the hypothetical neutral model results or the results from fire simulation of real landscape conditions using mapped surface and canopy fuels? Canopy fuels will be mapped by combining field measurements with topographic information and remotely sensed Landsat data within a classification and regression tree model to predict canopy fuel loads across the landscape. A neutral model approach to fire behavior modeling will compare hypothetical landscapes with both real landscapes and historical data on fire severity to assess the strength of topographic controls on fire intensity and the usefulness of this novel approach.The results of this study will address the role of topography in creating heterogeneity in vegetation community structure and composition across the landscape through its influence on fire intensity. Furthermore, this research will evaluate the impacts of fire suppression on changing the landscape location of high intensity fire-created patches. Some types of vegetation, especially in Lassen Volcanic National Park, but also in other locations throughout California and the US west, require high severity fire that has been vigorously suppressed. Using neutral models to assess the potential for high severity fire to create heterogeneity on the landscape will help both resource managers and fire fighters to make better decisions regarding wildfires, Wildfire Use, prescribed fire, and other fuel treatments in highly altered forests. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.