WCR: Vegetation Control of Ecohydrologic Processes

[00:233643 .菲利普斯作为陆地生态系统经济中的主要货币，水的获取、储存和使用就像人类经济中的金钱一样。像人类利用金融资源一样，植被通常不会以同样的瞬时速率吸收和释放水，而是通过将这一关键资源储存在内部储存器官中来缓冲水的供应和需求。了解植被如何以及何时捕获、储存和从根部向叶片输送水分，对于量化各种生态水文功能至关重要，如降雨径流关系和洪水响应的分水岭缓冲，以及生态系统对大气二氧化碳的吸收。本研究考察了马萨诸塞州哈佛森林植被对森林-大气水运的生理控制。本提案的具体目标是使用一种新的诊断方法来量化森林植被如何对环境刺激的变化作出水力反应。这里使用的方法对树冠和根系施加湿度、光照和降雨的短期扰动，然后追踪这些扰动在树木和土壤中的传播。这.ripple。效应包含植被内部关键水力特性和过程的综合特征，这些特性和过程支配着植被对生态系统水文的整体控制。这种新颖的方法是高度可操作的，并产生大的信噪比分析，但不会造成不可逆转的生态干扰，如损害或破坏植物的根，茎和枝。最重要的是，这种方法将对植被特性和生理、大气强迫和森林蒸发通量之间的动态关系和反馈产生基本见解。最后，该项目通过将研究与三个现有项目的重点教育活动相结合，提供了广泛的教育影响：

0233643PhillipsAs a major currency in the economy of terrestrial ecosystems, water is acquired, saved, and spent much like money in human economies. Like human use of financial resources, vegetation does not generally take up and release water at the same instantaneous rate, but rather buffers supply of and demand for water by banking this critical resource in internal storage organs. Understanding how and when vegetation captures, stores, and transports water from roots to and out of foliage is critical to quantifying diverse eco-hydrologic functions such as watershed buffering of rainfall-runoff relationships and flood responses, and ecosystem uptake of atmospheric carbon dioxide. This study examines the physiological controls exerted by vegetation on forest-atmosphere water transport, at Harvard Forest, Massachusetts. The specific objective of this proposal is to quantify, using a novel diagnostic method, how forest vegetation responds hydraulically to variation in environmental stimuli. The methodology used here imposes short-lived disturbances of humidity, light and rainfall on canopies and root systems, and then traces the propagation of these perturbations through trees and soil. This .ripple. effect contains the integrated signature of key hydraulic properties and processes within vegetation, that govern the overall control that vegetation exerts on ecosystem hydrology. This novel methodology is highly manipulative and produces large signal to noise ratios for analysis, but does not cause irreversible ecological disturbances, such as damage or destruction of plant roots, stems, and branches. Most importantly, this methodology will yield fundamental insights into the dynamic relationships and feedbacks among vegetation properties and physiology, atmospheric forcing, and evaporative fluxes from forests. Finally, this project provides broad educational impacts by integrating research with focused educational activities in three existing programs: