Collaborative Research: Quantifying the amount and functional significance of long-term stored-water in trees

合作研究：量化树木长期储存水的数量和功能意义

• 批准号: 2027609
• 负责人: Ryan Emanuel
• 金额: $ 34.32万
• 依托单位: North Carolina State University
• 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: 2020-10-01 至 2022-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2027609&HistoricalAwards=false
• 关键词: Collaborative; Research; Quantifying; amount; functional

Accurate modeling of water storage and fluxes in both natural and human-altered ecosystems is critical to managing global water resources under current-day and projected future climates. One important step towards accurate modeling involves determining how much water trees store, and how the amount of stored water varies through time and within tree organs. Another important step involves determining how stored water, and variations in stored water, affect the physiological behavior of individual trees and larger ecosystems. The investigators in this project will measure the amount of water stored in different organs of trees, determine how long water resides in these organs, and evaluate how long-term stored water affects whole-tree water use. The data collected will reveal novel information about how trees store and manage water, which will ultimately allow prediction of tree water storage and water movement through ecosystems in current and future climates. The study site in Idaho broadly represents many landscapes across the Intermountain West. Results from this study will be shared with local communities in the Snake River Plain region, and activities will involve students and faculty members from Tribal Colleges in the Pacific Northwest.Most models assume steady-state water flow through the soil-plant-atmosphere continuum. However, there is substantial storage of water in trees, and the residence times of water inside trees ranges from days to months. The total amount of stored water in trees and broader ecosystems, how long water resides in plants, and the ecohydrological implications of tree water storage are still not completely understood. Characterizing the duration of water storage and its impacts on tree ecohydrology are critical for improving hydrological models. The data collected in this study will be used to test the hypotheses that: (1) Water is stored in trees for many days, with differences in residence time correlating to species- and size-specific sapwood architecture and water-management strategies; (2) Stored water will buffer declines in water transport as soil moisture availability declines, at daily and seasonal timescales; (3) Inter-species differences in water storage and transport-buffering strategies will translate to differential responses in whole-tree water balance and fluxes due to changing climate in modeled scenarios. The work combines stable isotope tracers (deuterium), gas exchange, and hydraulic functional trait data collected in the field with process- and trait-based modeling to determine residence times of water in tree organs, how trees manage water storage and transport among organs, and how water storage regulates whole-tree water relations at hourly to monthly timescales.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.

在自然和人为改变的生态系统中对水的储存和通量进行精确建模，对于在当前和预测的未来气候下管理全球水资源至关重要。精确建模的一个重要步骤是确定树木储存了多少水，以及储存的水量如何随时间和树木器官变化。另一个重要的步骤是确定储存的水以及储存的水的变化如何影响单个树木和更大的生态系统的生理行为。该项目的研究人员将测量树木不同器官中储存的水量，确定水在这些器官中停留的时间，并评估长期储存的水如何影响整棵树的用水。收集到的数据将揭示关于树木如何储存和管理水的新信息，这将最终使人们能够预测树木在当前和未来气候下的水储存和水在生态系统中的运动。爱达荷州的研究地点大致代表了山间西部的许多景观。这项研究的结果将与斯内克河平原地区的当地社区分享，活动将涉及太平洋西北地区部落学院的学生和教职员工。大多数模型假定水流在土壤-植物-大气连续体中处于稳定状态。然而，树木中有大量的水储存，水在树木中的停留时间从几天到几个月不等。树木和更广泛的生态系统中储存的水的总量，水在植物中停留的时间，以及树木储水的生态水文含义仍未完全了解。表征储水持续时间及其对树木生态水文的影响对改进水文模型至关重要。本研究收集的数据将用于验证以下假设：(1)水分在树木中储存了很长时间，其停留时间的差异与物种和尺寸特定的边材结构和水管理策略有关；(2)在日和季节时间尺度上，随着土壤水分有效性的下降，储水会缓冲水运的下降；(3)在模拟情景下，物种间水分储存和运输缓冲策略的差异将转化为气候变化对全树水分平衡和通量的差异响应。这项工作结合了稳定同位素示踪剂（氘）、气体交换和在野外收集的水力功能性状数据，以及基于过程和性状的建模，以确定水在树木器官中的停留时间，树木如何管理水的储存和器官之间的运输，以及水的储存如何在每小时到每月的时间尺度上调节整个树木的水关系。该奖项反映了美国国家科学基金会的法定使命，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。