Collaborative Research: Extreme Events and Ecological Acclimation: Scaling from Cells to Ecosystems

森林是重要的自然和经济资源，支持动植物栖息地，保护水质，提供娱乐机会，为人们提供就业机会和木材。森林对气候变化的影响很敏感，包括干旱、天气变化和昆虫入侵。关于气候变化带来的反复干旱的影响，或者这些影响是如何从树木细胞到整个区域森林发生的，人们知之甚少。在过去的十年里，美国西部和西南部的大部分地区都发生了干旱。这些干旱对森林造成了严重后果，例如大范围的森林死亡。这一奖项将弥补科学认识上的一个根本差距，对美国西部森林的未来具有深远的影响。在一次严重干旱中幸存下来的树木是更脆弱还是更不容易受到下一次干旱的影响？在两年的时间里，这项研究将评估水分压力，并将这些干旱脆弱性的测量从单个树枝的细胞水平扩大到西部四个州的整个生态系统。它将利用树木核心记录、植物种群测量、树木水分运输解剖以及整个生态系统碳和水通量的测量。该项目的最终目标是建立一个跨不同空间尺度的预测框架，以预测哪些森林最脆弱，以及可存活的干旱回归频率。该项目包含了对本科生、研究生、博士后和职业生涯早期阶段的科学家进行培训的广泛承诺。该项目的研究将直接与教学活动联系起来，将研究结果和项目纳入北亚利桑那大学、普林斯顿大学和里诺内华达大学的五门本科生和两门研究生课程。这项研究将使整个大陆的干旱监测成为可能。这项研究将发展建立全大陆森林干旱监测网络所需的传感器能力。开发的技术可以帮助美国森林管理局的土地管理人员管理美国林地。将开发和部署高分辨率气象和植物水分状况传感器，并将在广泛的空间尺度上测量森林树冠覆盖率。此外，这些测量还可以补充国家森林调查和分析计划等国家森林安全信息。

Forests are vital natural and economic resources that support habitat for plants and animals, protect water quality, offer opportunities for recreation and provide jobs and wood for people. Forests are sensitive to the effects of climate change including drought, shifts in weather, and invasion by insects. Little is known about the effects of repeated droughts brought on by climate change or how these effects occur from the tree cells to entire regional forests. Droughts in the past decade have occurred across much of the western and southwestern United States. These droughts have led to severe consequences on forests, such as widespread forest die-off. This award will answer a fundamental gap in scientific understanding with profound implications for the future of western U.S. forests. Are trees that survive a severe drought more vulnerable or less vulnerable to the next drought? Over two years, the research will assess water stress and scale these measurements of drought vulnerability from the cell level in individual branches to entire ecosystems across four western States. It will draw on tree-core records, measurements of plant populations, anatomy of tree water transport, and measurements of whole-ecosystem fluxes of carbon and water. The ultimate goal is a predictive framework across different spatial scales that will allow prediction of which forests are most vulnerable and the return frequency of drought that's survivable versus lethal.This project incorporates an extensive commitment to training of scientists at the undergraduate, graduate, post-doctoral, and early-career levels. The project's research will be directly linked with teaching activities by incorporating findings and projects into five undergraduate and two graduate courses across Northern Arizona University, Princeton University, and the University of Nevada, Reno. The research will enable entire continent wide drought monitoring. The research will develop sensor capacity needed for establishing a continent-wide forest drought-monitoring network. The technology developed can aid land managers with the USFS in managing US Forest Lands. High resolution meteorological and plant water status sensors will be developed and deployed, and measurements of forest canopy cover will be made across a broad spatial scale. In addition, these measurements can also supplement the national USFS information such as the Forest Inventory and Analysis program.