The role of short duration climate events in reducing natural tree regeneration in forests and woodlands of the southwestern United States

短期气候事件在减少美国西南部森林和林地自然树木再生中的作用

• 批准号: 2020185
• 负责人: Matthew Petrie
• 金额: $ 14.96万
• 依托单位: University of Nevada Las Vegas
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2020185&HistoricalAwards=false
• 关键词: role; short; duration; climate; events

Forests in the southwestern United States are declining and their future is uncertain. Much previous research focused on how disturbances such as wildfire, insect outbreaks, and severe drought killed mature trees. Yet, young trees are also failing to grow from seed to adulthood in some locations, suggesting that failure of the natural regeneration process may also be important. Changes in temperature and moisture conditions are becoming less favorable for juvenile tree survival. This may lead to even more severe forest ecosystem declines in the future. This project will examine how short duration climate events such as timing of summer rainfall support and limit juvenile tree survival. The role of local environments, and the stress tolerance of juvenile trees has not received substantial research attention. This project will train undergraduate and graduate students, including individuals from under-represented groups. The University of Nevada-Las Vegas is a Minority-Serving Institution. This project will also enhance scientific infrastructure by establishing three vegetation and climate monitoring towers. Research results will be useful to regional forest managers, who will gain critical information for understanding the future of forest ecosystems in the southwestern United States. This research will use ground-based field instrumentation and remote sensing to study the specific environmental conditions that initiate juvenile tree mortality events. The three dominant coniferous tree species in the region will be studied: ponderosa pine, pinon pine, and juniper. This instrumentation will be deployed over multiple years and across diverse landscapes in the southwestern U.S. This work hypothesizes that juvenile tree mortality will be caused by environmental conditions that are different and less severe than those determined experimentally. However, it is likely that prolonged environmental stress will be required to kill juvenile trees due to the favorable microclimates where they are located. Additionally, improved mechanistic insight on juvenile tree mortality will be used to enhance existing forecasts of natural forest regeneration in scenarios of 21st century climate change. When completed, this research will improve our understanding of how the interaction of climate, environment, and tree stress tolerance will shape the future of forests in the southwestern U.S.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.

美国西南部的森林面积正在减少，其未来不确定。以前的许多研究都集中在野火，昆虫爆发和严重干旱等干扰如何杀死成熟的树木。然而，在一些地方，小树也未能从种子生长到成年，这表明自然再生过程的失败也可能很重要。温度和湿度条件的变化对幼树的生存越来越不利。这可能导致未来森林生态系统更加严重的衰退。该项目将研究如何短时间的气候事件，如夏季降雨的时间支持和限制幼树的生存。当地环境的作用，以及幼树的抗逆性还没有得到大量的研究关注。该项目将培训本科生和研究生，包括来自代表性不足群体的个人。内华达大学拉斯维加斯分校是一所少数民族服务机构。该项目还将通过建立三个植被和气候监测塔来加强科学基础设施。研究结果将有助于区域森林管理人员，他们将获得关键信息，了解美国西南部森林生态系统的未来。这项研究将使用地面现场仪器和遥感技术来研究启动幼树死亡事件的特定环境条件。将研究该地区的三种主要针叶树种：黄松、松和杜松。这种仪器将部署在多年来，在美国西南部的不同景观这项工作假设，幼树死亡率将由不同的环境条件，比那些确定的实验严重。然而，由于它们所处的有利小气候，可能需要长时间的环境压力才能杀死幼龄树。此外，将使用改进的机制洞察幼树死亡率，以提高现有的预测天然林再生的情况下，21世纪气候变化。完成后，这项研究将提高我们对气候，环境和树木压力耐受性的相互作用将如何塑造美国西南部森林的未来的理解。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。