Collaborative Research: Hydrologic-Nutrient Cycle Interaction in Small Undisturbed and Man-Manipulated Ecosystems

本研究将继续研究北方阔叶林生态系统退化和扰动过程中空气-陆地-植物-水-人的相互作用。从历史上看，哈伯德布鲁克生态系统研究将生态系统生物地球化学和森林生长的长期调查与详细的实验相结合，包括实验室和地块水平的研究，整个生态系统的操纵，以及计算机模型的开发和应用。对降水投入、生态系统库和河流流出的研究将继续进行。这项长期的生物地球化学研究将通过质子预算的发展和元素循环相互作用的分析，与正在进行的和拟议的过程级研究相结合。这项研究包括两项新举措。首先，使用（NH4）2SO4、H2SO4、Na2SO4和CaSO4的地块和流域级化学操作将研究当今人为引起的氢离子、硫、氮和金属阳离子循环的变化。其次，本研究将验证植物生长时间和生理过程与水文和养分输出调节有关的新假设。哈伯德布鲁克北部阔叶林生态系统的研究是一个多研究者/多机构的努力。大多数工作将在新罕布什尔州的哈伯德布鲁克实验森林进行，但要调查的概念和过程通常适用于许多类型的生态系统。同过去一样，这项研究将有助于对森林生态系统的基本了解，并提供对更好地管理其宝贵的自然资源有用的资料。项目团队是优秀的，由经过验证的协作执行者组成。美国农业部与林务局的合作是相当积极的。学校设施是一流的。生态系统研究计划自信地建议，这个合作的，为期四年的持续奖励。

This research will continue investigations of air-land-plant- water-human interactions in aggrading and disturbed northern hardwood forest ecosystems. Historically, the Hubbard Brook Ecosystem Study has coupled long-term investigation of ecosystem biogeochemistry and forest growth with detailed experimentation, including laboratory and plot-level studies, whole ecosystem manipulations, as well as the development and application of computer models. Studies of precipitation inputs, ecosystem pools and stream outflow will be continued. This long-term biogeochemical research will be integrated with ongoing and proposed process-level studies through the development of proton budgets and analysis of element cycle interactions. The research includes two new initiatives. First plot- and watershed-level chemical manipulations using (NH4)2SO4, H2SO4, Na2SO4 and CaSO4 will investigate present-day, anthropogenically-induced changes in hydrogen ion, sulfur, nitrogen and metallic cation cycles. Second, the research will test a new hypothesis relating the timing of plant growth and physiological processes to regulation of hydrological and nutrient export. Research on northern hardwood forest ecosystems at Hubbard Brook is a multi- investigator-/multi-institutional effort. Most work will be conducted at the Hubbard Brook Experimental Forest, NH, yet the concepts and processes to be investigated are generally applicable to many types of ecosystems. This research will, as in the past, contribute to the fundamental understanding of forest ecosystems and yield information useful to the better management of their valuable natural resources. The project team is excellent and comprises proven collaborative performers. USDA/Forest Service collaboration is quite positive. Institutional accommodations are first-rate. The Ecosystem Studies Program confidently recommends that this collaborative, four-year continuing award be made.