TARP Identifying Critical Thresholds for Acute Response of Plants and Ecosystems to Water Stress at Walker Branch Watershed, 2002-2005

This dataset contains data from a manipulative field study aimed at identifying critical thresholds for acute response of plants and ecosystems to water stress (TARP) that took place at Walker Branch Watershed in Oak Ridge, Tennessee from 2002-2005 (2002-06-20 to 2005-12-16). The study used understory tents for the removal of 100% of the growing-season throughfall and stem flow, to provide data on the impact of acute drought on mechanisms responsible for growth and mortality of deciduous forest canopy trees representative of common plant functional types (Liriodendron and Quercus). Through three years of manipulation (2003, 2004 and 2005; pretreatment measurements in 2002) various measures of tree response to surface moisture deficits were recorded including root and leaf traits, plant nonstructural carbohydrates status, hourly sapflow, basal area, and periodic observations of foliar photosynthesis and conductance. Additionally, environmental data such as air and soil temperature, soil water content, and soil matric potential were recorded. This dataset contains data 16 files in comma-separate (*.csv) format. Additional metadata are provided: 16 data dictionaries and a file-level metadata file in comma separate (*.csv) format and a user guide in PDF (*.pdf) format.本数据集源自2002年6月20日至2005年12月16日（2002-2005年）于田纳西州橡树岭市沃克分支流域（Walker Branch Watershed）开展的一项控制性野外实验研究，旨在明确植物与生态系统对水分胁迫的急性响应临界阈值（Thresholds for Acute Response of Plants and Ecosystems to Water Stress, TARP）。该研究通过布设林下遮雨棚移除生长季全部穿透降水（throughfall）与茎流（stem flow），以获取代表常见植物功能型的落叶林冠层树木（鹅掌楸属*Liriodendron*与栎属*Quercus*）的生长与死亡机制受极端干旱影响的相关数据。本次操控实验为期三年（2003、2004、2005年，2002年完成预处理测量），共记录了多种树木对地表水分亏缺的响应指标，包括根系与叶片性状、植物非结构性碳水化合物（nonstructural carbohydrates）状态、小时尺度树液流量（sapflow）、基径面积（basal area），以及定期观测的叶片光合速率（foliar photosynthesis）与气孔导度（conductance）。此外还同步采集了空气与土壤温度、土壤含水量、土壤基质势（soil matric potential）等环境数据。本数据集包含16个逗号分隔格式（*.csv）的数据文件，附带的元数据包括：16份数据字典、1份逗号分隔格式（*.csv）的文件级元数据文件，以及一份PDF格式（*.pdf）的用户指南。