Postdoctoral Fellowship: EAR-PF: How Does Critical Zone Water Storage Impact Forest Drought Stress Across Complex Terrain?

博士后奖学金：EAR-PF：关键区域蓄水如何影响复杂地形的森林干旱胁迫？

• 批准号: 2305616
• 负责人: Karla Jarecke
• 金额: $ 18万
• 依托单位: Jarecke, Karla M
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2305616&HistoricalAwards=false
• 关键词: Postdoctoral; Fellowship; EAR; PF; How

Climate change is causing more frequent hot droughts, which can lead to extreme water stress for tall trees in forest ecosystems. The ways that trees deal with water stress under extreme drought are not well understood. To address this challenge, this research will address fundamental questions about how water stored below ground affects tree growth and physiological water stress. Trees can adapt their physical structure to deal with chronic water stress, but it is unclear how subsurface water storage dynamics do or do not lead to compensatory responses in tree physiology. For example, will a tree faced with intermittent drought make the same physiological adjustments as those faced with perennial drought? Questions like these are particularly relevant in places where water is already a limiting factor for tree growth and could become more limiting in the future. This study will take place in Colorado, USA, where snowpack in montane forests is declining due to climate warming. By understanding tree water stress across complex mountainous terrain, the results of this study will be broadly relevant for scientists and forest managers seeking to improve forest drought resilience and ensure sustainable management of water resources. The role of deep “critical zone” water storage in mitigating forest water stress during extreme drought may be confounded by the way trees adapt structurally and physiologically to subsurface hydrological conditions. For example, water stored in deep, highly weathered bedrock may mitigate seasonal water stress in trees. However, trees with access to deep water storage may be vulnerable to hydraulic failure during prolonged drought if they have maladapted physiological traits. This project employs field-based investigations using seismic surveys and electrical resistivity tomography to gather data on belowground structure and water storage along hillslope transects in the Boulder Creek Watershed in Colorado, USA, part of the Dynamic Water Critical Zone Cluster Network. Information on subsurface water storage dynamics will be combined with tree ecophysiological measurements to reveal how critical zone water storage influences forest drought vulnerability and transpiration fluxes in semi-arid environments. Ultimately, this research seeks to improve mechanistic understanding of how climatic conditions and subsurface structure regulate water fluxes across complex mountainous terrain.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.

气候变化正在导致更频繁的干旱，这可能导致森林生态系统中高大树木的极度缺水。树木在极端干旱下应对水分胁迫的方式还不太清楚。为了应对这一挑战，这项研究将解决地下储存的水如何影响树木生长和生理水分胁迫的基本问题。树木可以调整其物理结构，以应对慢性水分胁迫，但目前还不清楚地下水储存动态做或不导致树木生理的补偿反应。例如，一棵树在面对间歇性干旱时，是否会做出与常年干旱时相同的生理调整？像这样的问题在水已经是树木生长的限制因素并且在未来可能变得更加限制的地方特别相关。这项研究将在美国科罗拉多进行，由于气候变暖，那里的山地森林积雪正在减少。通过了解复杂山区地形的树木水分胁迫，这项研究的结果将与寻求提高森林抗旱能力和确保水资源可持续管理的科学家和森林管理人员广泛相关。在极端干旱期间，深层“临界区”蓄水在减轻森林水分胁迫方面的作用可能会被树木在结构和生理上适应地下水文条件的方式所混淆。例如，储存在深度、高度风化的基岩中的水可以减轻树木的季节性水分压力。然而，树木与访问深储水可能容易受到液压故障在长期干旱，如果他们有不适应的生理特性。该项目采用基于现场的调查，使用地震勘测和电阻率层析成像，收集数据的地下结构和水存储沿着山坡样带在美国科罗拉多州的博尔德溪流域，动态水临界区集群网络的一部分。地下水储存动态的信息将结合树木的生态生理学测量，以揭示关键区水储存如何影响森林干旱脆弱性和半干旱环境中的蒸腾通量。最终，这项研究旨在提高对气候条件和地下结构如何调节复杂山区地形水通量的机械理解。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。