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，为动植物提供栖息地，保护水质，提供娱乐机会，并为人们提供就业和木材。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。人们对气候变化带来的反复干旱的影响知之甚少，也不知道这些影响是如何从树木细胞到整个区域森林发生的。在过去的十年里，干旱发生在美国西部和西南部的大部分地区。这些干旱给森林带来了严重的后果，比如大面积的森林死亡。这个奖项将填补科学认识上的一个基本空白，对美国西部森林的未来产生深远的影响。在一次严重干旱中幸存下来的树木在下一次干旱中是更脆弱还是更脆弱？在两年多的时间里，这项研究将评估水资源压力，并将这些干旱脆弱性的测量从单个分支的细胞水平扩展到西部四个州的整个生态系统。它将利用树核记录、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测量。最终目标是建立一个跨越不同空间尺度的预测框架，从而预测哪些森林最脆弱，以及干旱的复发频率，是生存的还是致命的。该项目包括对本科生、研究生、博士后和早期职业水平的科学家进行广泛的培训。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、普林斯顿大学和内华达大学里诺分校的五门本科和两门研究生课程。这项研究将使整个大陆范围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USFS的土地管理者管理美国的森林土地。将开发和部署高分辨率气象和植物水分状况传感器，并在广泛的空间尺度上进行森林冠层覆盖的测量。此外，这些测量还可以补充国家USFS信息，如森林清查和分析计划。

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.