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.

气候变化导致更频繁的炎热干旱，这可能导致森林生态系统中的高大树木面临极端的水分胁迫。为了应对这一挑战，这项研究将解决一些基本问题。关于地下储存的水如何影响树木生长和生理水分胁迫，树木可以调整其物理结构以应对长期水分胁迫，但尚不清楚地下蓄水动态如何导致或不导致树木生理学的补偿反应。 ，一棵树是否会面临间歇性干旱与面临常年干旱的人进行相同的生理调整吗？在水已经成为树木生长的限制因素并且未来可能变得更加限制的地方，此类问题尤其重要。这项研究将在美国科罗拉多州进行。由于气候变暖，山地森林的积雪正在减少。通过了解复杂山区地形的树木水分压力，这项研究的结果将对寻求提高森林抗旱能力和确保水资源可持续管理作用的科学家和森林管理者具有广泛的意义。深层“临界区”蓄水在极端干旱期间减轻森林水压力可能会因树木在结构和生理上适应地下水文条件的方式而受到干扰，例如，储存在深层、高度风化的基岩中的水可能会减轻树木的季节性水压力。如果蓄水池具有不适应的生理特征，则在长期干旱期间可能容易出现水力衰竭。该项目采用地震勘测和电阻率层析成像技术进行实地调查，收集有关沿山坡横断面的地下结构和蓄水量的数据。美国科罗拉多州的博尔德溪流域是动态水临界区集群网络的一部分，有关地下水储存动态的信息将与树木生态生理测量相结合，以揭示临界区水储存如何影响半干旱环境中的森林干旱脆弱性和蒸腾通量。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水通量的机制理解。该奖项是 NSF 的法定使命，并通过使用基金会的评估进行评估，被认为值得支持。智力价值和更广泛的影响审查标准。