CAREER: Refining forest management strategies to maximize hydrologic gains from snow dominated watersheds

森林高地的季节性降雪是美国西部大部分地区和世界上其他降雪为主地区的重要水源。除了提供融水外，森林还提供社会重视的商品和服务，包括木材生产、碳封存、生物多样性保护、养分拦截和向大气交换水。为了维持这些生态系统服务，经常实施森林管理措施（fmp），如机械间伐、造林和防火林砍伐。然而，这些fmp可能会产生意想不到的后果，包括积雪融化和峰值流量增加，从而导致侵蚀，破坏溪流稳定，造成水资源短缺，并降低水质和生态系统健康。水和森林管理者需要在最大限度提高森林生产力和尽量减少对水资源的影响之间取得平衡。该项目将研究由于fmp而改变的森林形态对雪占主导的森林的高峰和融化季节流量的作用。研究结果将有助于减轻自然和管理森林变化带来的有害水文影响，并增强美国西部和其他由这些森林提供的雪水支持的地区的经济恢复能力。研究和教育将在多个教育层次进行整合。K-12的外展将通过决策室实现，这是一个小组模拟练习，旨在：1)围绕特定的水主题发展知识；2)了解决策和实施基于科学的解决方案所涉及的权衡。决策室将在北卡罗来纳科学节上与莫尔黑德天文馆科学中心合作实施，该中心有一个吸引不同学生群体的历史。在大学一级，在这个项目中开发的数据和模型将被纳入水量和水质评估课程。北卡罗来纳州公立学校、杜克大学（Duke University）和爱达荷大学（University of Idaho）的教育活动将激励新一代科学家和工程师去探索、合作和教学。该项目将加深对fmp（如变薄和缝隙形成）如何影响积雪积累、融雪以及随之而来的水文响应的理解。该研究将通过协同观测和模拟，推进森林流域辐射转移、积雪和融化及其水文响应的综合评估。具体而言，该项目将：1)开发、验证和评估基于物理的异质性森林辐射模型；2)通过将辐射模型与融雪和积累模型以及分布式水文模型相结合，评估森林斑块和林隙配置变化对水文响应的影响。模型的假设检验、参数化、评估和验证将在多个地点进行，包括云母溪实验流域（爱达荷州）、南塞拉临界区观测站（加利福尼亚州）和尼沃特岭长期生态研究站（科罗拉多州）。经过验证的模型将评估是否存在最优的森林斑块和林隙配置，这些配置既可以最大限度地减少fmp的负面影响，也可以提高水文效益。项目期间开发的综合模型将向更广泛的社区发布，将允许对森林变化情景进行强有力的水文影响分析，并为测试未来可持续水资源和森林管理战略提供基础。

Seasonal snow in forested uplands is a critical water source for most of the western United States and other snowfall-dominated regions of the world. In addition to providing melt water, the forests also provide goods and services valued by society, including timber production, carbon sequestration, biodiversity preservation, nutrient interception, and water exchange to the atmosphere. To sustain these ecosystem services, forest management practices (FMPs) such as mechanical thinning, gap creation, and firebreak cutting are often implemented. However, these FMPs can have unintended consequences, including increased snow melt and peak flow that can cause erosion, destabilize streams, produce water shortages, and degrade water quality and ecosystem health. Water and forest managers need to strike a balance between maximizing forest productivity and minimizing impacts on water resources. This project will study the role of altered forest configurations due to FMPs on peak and melt-season streamflow in snow-dominated forests. The results will lead to mitigation of harmful hydrologic impacts from both natural and managed forest alterations and enhance the resilience of economies in the western U.S. and other areas supported by snow-fed water from these forests. Research and education will be integrated across multiple educational levels. K-12 outreach will be achieved through the Decision Room, a group simulation exercise to: 1) develop knowledge around specific water topics and 2) understand trade-offs involved in decision making and implementation of science-based solutions. The Decision Room will be implemented in collaboration with Morehead Planetarium Science Center at the North Carolina Science Festival, which has a history of engaging a very diverse student population. At the university level, data and models developed in this project will be integrated into courses on Water Quantity and Quality Assessment. Educational activities in North Carolina public schools, at Duke University and at the University of Idaho, will inspire a new generation of scientists and engineers to explore, collaborate and teach. The project will develop an improved understanding of how FMPs, such as thinning and gap creation, impact snow accumulation, snowmelt, and the consequent hydrologic response. The research will advance integrated assessment of radiation transfer, snow accumulation and melt, and the consequent hydrologic response in forested watersheds, through synergistic observation and modeling. Specifically, the project will: 1) develop, validate, and evaluate a physics-based forest radiation model for heterogeneous forests and 2) assess the impacts of changes in forest patch and gap configuration on hydrologic response, by integrating the radiation model with a snow melt and accumulation model and a distributed hydrologic model. Hypothesis testing, and parameterization, evaluation, and validation of the models will be performed at multiple sites including the Mica Creek Experimental Watershed (Idaho), Southern Sierra Critical Zone Observatory (California) and Niwot Ridge Long Term Ecological Research site (Colorado). The validated model will evaluate existence of optimal forest patch and gap configurations that may either minimize the negative impacts of FMPs or enhance hydrologic benefits. The integrated model developed during the project, to be released to the broader community, will allow robust hydrology impact analyses for forest alteration scenarios and provide a foundation for testing future sustainable water resource and forest management strategies.