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主导地区的重要水源。除了提供融水外，森林还提供社会所重视的商品和服务，包括木材生产、碳固存、生物多样性保护、养分拦截和与大气的水交换。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，创建间隙和防火带切割。然而，这些FMP可能会产生意想不到的后果，包括增加积雪融化和峰值流量，这可能会导致侵蚀，使河流不稳定，造成水资源短缺，并降低水质和生态系统健康。水和森林管理人员需要在最大限度地提高森林生产力和最大限度地减少对水资源的影响之间取得平衡。该项目将研究由于FMPs在雪为主的森林中对高峰和融化季节径流的作用，改变了森林配置。研究结果将有助于减轻自然和管理森林变化造成的有害水文影响，并增强美国西部和其他受这些森林雪水支持的地区的经济恢复力。研究和教育将在多个教育层次上进行整合。K-12外展将通过决策室实现，这是一项小组模拟练习，旨在：1）发展有关特定水主题的知识，2）了解决策和实施基于科学的解决方案中涉及的权衡。决策室将在北卡罗来纳州科学节上与莫尔黑德天文馆科学中心合作实施，该科学节有着吸引多样化学生的历史。在大学一级，该项目开发的数据和模型将纳入水量和水质评估课程。北卡罗来纳州公立学校、杜克大学和爱达荷州大学的教育活动将激励新一代科学家和工程师进行探索、合作和教学。 该项目将加深对FMP如何影响积雪、融雪以及随之而来的水文响应的理解，如变薄和间隙形成。这项研究将通过协同观测和建模，推进对辐射转移、积雪和融化以及森林流域随之产生的水文反应的综合评估。具体而言，该项目将：1）开发，验证和评估基于物理学的森林辐射模型为异质森林和2）评估森林斑块和间隙配置的变化对水文响应的影响，通过整合辐射模型与积雪融化和积累模型和分布式水文模型。将在多个地点进行模型的假设检验、参数化、评价和验证，包括云母溪实验流域（爱达荷州）、南部塞拉临界区观测站（加州）和尼沃特岭长期生态研究地点（科罗拉多）。经验证的模型将评估是否存在最佳的森林斑块和间隙配置，可以最大限度地减少FMP的负面影响或提高水文效益。在项目期间开发的综合模型将向更广泛的社区发布，它将有助于对森林变化情景进行强有力的水文影响分析，并为测试未来的可持续水资源和森林管理战略奠定基础。

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.