Collaborative Research: RUI: Recovery trajectories of the hillslope green water cycle after rapidly repeated wildfires

合作研究：RUI：快速重复野火后山坡绿水循环的恢复轨迹

• 批准号: 1738228
• 负责人: Kevan Moffett
• 金额: $ 28.67万
• 依托单位: Washington State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1738228&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; Recovery; trajectories

As temperatures rise and rain and snowfall become more intermittent, wildfire recurrence is expected to increase in forested areas. Although wildfires that re-burn an area after only a short time (10 years) have been unusually common over the last 30 years, the mechanisms governing these ?rapid reburns? are incompletely understood. It may be that decreasing water availability, i.e., an altered hydrological cycle, on forested hillslopes is changing the controls on plant regrowth after fire, and so on subsequent wildfires. However, there are almost no data on the soil water resources that plants need following fires, the spatial and temporal changes in soil moisture in burned areas over multiple years after fires, or moisture feedbacks with vegetation regrowth. This research addresses this critical gap in data on post-reburn hillslope hydrology and ecohydrologic system recovery over time and will also help identify whether reburns might mitigate or worsen the downstream flood and landslide risks that often accompany higher post-fire water flows. The new knowledge generated by this research will be produced in close coordination with federal and state water and forest managers, including a series of research-management workshops to improve research communication with management practices. The project will also engage with the nonprofit community via a volunteer organization related to the field area and with the public via creation of a temporary science exhibit for display at a local museum and also for portable education at local preschools and elementary schools during ?meet-a-scientist? visits and will expand research a opportunities for undergraduate and graduate researchers.This research aims to understand (1) how hillslope hydrological response differ with increasing numbers of natural reburns and with time since last fire; (2) how the patterns and feedbacks between the recovery of hillslope soil moisture and evapotranspiration fluxes are linked to the recovery of vegetation, and how they vary with number of reburns, seed-source distances, and time since fire; and (3) how the gradual change in the hillslope water balance relates to downstream river flow dynamics after a fire or reburn under variable climate influence. This research will test multiple components of an overarching hypothesis that there are both spatio-temporal (correlative) and biophysical (causative), linking soil moisture and soil hydraulic process changes following reburns. In addition, it addresses how the vegetation regrowth provides the fuel load for subsequent fires, and how downstream flows and flood risks recede over time following multiple wildfires. Soil moisture, matric potential, texture, water repellency, infiltration, and hydraulic property measurements, live vegetation, and woody debris will be mapped across six 0.25 ha field sites and monitored over time throughout the study, building on an additional two seasons of preliminary data. Field methods include in situ sensors and data loggers, 3D geophysical surveys of soil moisture, micrometeorological monitoring, and detailed vegetation ecology surveys including tree seedling presence and survival. The six exemplary field sites on the southern flank of Mt. Adams, WA, are of similar ecology, climate, slope, elevation, aspect, distance to unburned forest, and past severity per fire, but differ in the number of past fires (1 to 3 in the last 13 years, and an unburned control) and time since fire. Modeling of evapotranspiration will be conducted for major vegetation and bare land cover classes and applied in a spatially and temporally extensive manner across two relevant watersheds with the aid of remote sensing data and long-term climate, drought, and streamflow time-series. This modeling analysis will seek to better understand the spatiotemporal dynamics of the post-fire hillslope water cycle and its relation to streamflow dynamics after different numbers of wildfire reburns and different recovery intervals after fire.

随着温度的升高，降雨和降雪变得更加间歇，预计在森林地区，野火复发将增加。尽管在过去的30年中，仅短时间（10年）就重新燃烧区域的野火在很普遍的情况下是异常普遍的，但管理这些快速袭击的机制？不完全理解。森林山坡上的水的可用性降低，即水文周期的变化，正在改变火灾后植物再生的控制，等等随后的野火。但是，几乎没有关于植物在火灾之后需要的土壤水资源的数据，火灾后多年燃烧区域的土壤水分的空间和时间变化，或带有植被再生的水分反馈。这项研究解决了随着时间的流逝，有关雷伯恩山坡水文学和生态水文系统恢复的数据的这一关键差距，还将有助于确定脑电图是否可能减轻或恶化下游的洪水，而降落后坡道通常伴随着更高的火后水流。这项研究产生的新知识将与联邦和州的水和森林经理密切协调，包括一系列研究管理研讨会，以改善与管理实践的研究沟通。该项目还将通过与现场区域相关的志愿组织与非营利社区互动，并通过创建临时科学展览会在当地博物馆展出，并在当地的学龄前和小学上在“ Meet-A-Scientist”期间在当地的学前班和小学上进行便携式教育？访问并将扩大研究本科和研究生研究人员的机会。这项研究的目的是了解（1）山坡水文反应如何随着自然rob的数量增加以及自上次大火以来的时间而有所不同； （2）山坡土壤水分和蒸散通量的恢复之间的模式和反馈与植被的恢复以及它们如何随着落下数量，种子源距离以及自火之后的时间而变化； （3）山坡水平的逐渐变化与在可变的气候影响下发生火灾或爆炸后的下游河流流动性如何相关。这项研究将测试总体假设的多个组成部分，即存在时空（相关）和生物物理（因果关系），将土壤水分和土壤液压过程变化联系在一起。此外，它解决了植被再生如何为随后的火灾提供燃料负载，以及多次野火后随着时间的流逝，下游流动和洪水风险如何消退。土壤湿度，质子潜力，质地，驱动性，浸润和液压性能测量，实时植被和木质碎屑将在六个0.25公顷的野外地点进行映射，并在整个研究过程中随着时间的推移进行监测，并在其他两个季节的初步数据上进行了构建。现场方法包括原位传感器和数据记录仪，土壤水分的3D地球物理调查，微量流程学监测以及详细的植被生态调查，包括树幼苗的存在和生存。华盛顿州亚当斯山南侧的六个示例地点具有相似的生态学，气候，坡度，海拔，侧面，到未燃烧的森林的距离以及每场火灾的严重程度，但过去13年的1至3年有所不同，并且自火灾中没有被燃烧的时间）和时间。将针对主要的植被和​​裸露的土地覆盖类别进行蒸散的建模，并在两个相关分水岭上以遥感数据和长期气候，干旱，干旱和流量时序列进行空间和时间上的范围进行应用。这种建模分析将旨在更好地了解后火山坡水周期的时空动力学及其与流量动态的关系，在不同数量的野火爆发和火灾后不同的恢复间隔之后。