Collaborative Research: Understanding the Impacts of Ice Storms on Forest Ecosystems of the Northeastern United States

冰暴是世界各地温带和北部森林地区常见的强大冬季天气事件。这些风暴可能会对森林生态系统造成灾难性的短期生态和社会经济影响，原因是树枝在重冰负荷下折断和倒塌。从长远来看，由于森林生产力和物种构成的变化；森林病虫害和病原体的毒力；以及由于更大的火灾燃料负荷而增加的火灾风险，它们的遗产也可能持续存在。尽管冰暴在塑造森林生态系统方面发挥了重要作用，但人们对冰暴及其影响的了解仍然有限。冰暴在时间和空间上的不可预测性在很大程度上限制了过去的调查，只限于大风暴之后的案例研究。美国东北部、加拿大东部和其他地区冰暴的严重程度，加剧了人们对这些风暴在塑造未来森林方面所起作用的更大澄清的必要性。北卡罗来纳州哈伯德·布鲁克实验森林的科学家们将进行一项多方面的研究计划，其中包括一项新颖的冰暴操纵实验、长期现场数据以及气候和生态系统建模。这项研究将为科学界、土地管理者和相关公众提供更多关于这些强大的和极端的冬季天气事件对北部阔叶林生态系统动态的影响的深入了解。这项综合研究计划建立在哈伯德·布鲁克和该地区先前工作的基础上，包括2012年进行的试点冰暴实验；关于森林生态系统对严重的“1998年冰暴”的响应的大量研究；以及一套新的历史气候重建，允许量化导致冰暴的气象条件。具体地说，研究人员将：(1)开发高分辨率全球气候模式模拟，以评估未来气候变化下冰暴的严重程度、频率和程度；(2)评估短期(2-3年)生态系统对四种不同强度和2种频率的实验冰事件的响应；(3)评估森林植被对1998年风暴的较长期(17年以上)响应；(4)利用实验结果和长期观测结果，改进已建立的森林生态系统生物地球化学模型，以模拟冰暴干扰；以及(V)利用高分辨率气候模拟的结果来驱动改进的生物地球化学模型，以预测未来冰暴对北部阔叶林生态系统通量和碳氮库的影响。这项研究将与更广泛的影响结合起来，涉及：(I)利用传感器技术让STEM残疾学生参与研究；(Ii)与当地利益攸关方就冰暴的影响进行对话；(Iii)制作关于冰暴的形成及其与极端事件和气候变化的相关性的视频；(Iv)本科生、研究生和博士后培训。

Ice storms are powerful winter weather events common to temperate and boreal forest regions worldwide. These storms are capable of catastrophic short-term ecological and socio-economic impacts on forest ecosystems due to branch breakage and toppling of trees under heavy ice loads. Their legacy can also persist over the longer-term through changes in forest productivity and species composition; the virulence of forest pests and pathogens; and increased risk of fire due to greater fire fuel loads. Despite their influential role in shaping forest ecosystems, knowledge of ice storms and their impacts remains limited. The temporally and spatially unpredictable nature of ice storms has largely confined past investigations to case studies following major storms. The severity of ice storms in the northeastern United States, Eastern Canada and elsewhere has heightened the need for greater clarity on the role of these storms in shaping future forests. Scientists at the Hubbard Brook Experimental Forest in NH will conduct a multi-faceted program of research that includes a novel ice storm manipulation experiment, long-term field data, and climate and ecosystem modeling. This research will provide the scientific community, land managers and the concerned public greater insight on the impacts of these powerful, and extreme winter weather events on the ecosystem dynamics of northern hardwood forests.This integrated program of research is built on a foundation of previous work at Hubbard Brook and the region, including a pilot ice storm experiment conducted in 2012; a significant body of research on the forest ecosystem response to the severe "Ice Storm of 1998"; and a new set of historical climate reconstructions which allow for the quantification of the meteorological conditions that lead to ice storms. Specifically, the investigators will: (i) develop high-resolution global climate model simulations to evaluate the severity, frequency and extent of ice storms under future changing climate; (ii) evaluate short-term (2-3 year) ecosystem response to four different intensities and two frequencies of experimental ice events; (iii) evaluate longer-term (17+ years) response of forest vegetation to the 1998 storm; (iv) use results from the experiment and the long term observations to refine an established forest ecosystem biogeochemical model to simulate ice-storm disturbance; and (v) use the results from the high-resolution climate simulations to drive the improved biogeochemical model to project future ice storm impacts on ecosystem fluxes and pools of carbon and nitrogen in a northern hardwood forest. This research will be integrated with broader impacts involving: (i) the use of sensor technology to engage STEM students with disabilities in the study; (ii) a dialog on the impacts of ice storms with local stakeholders; (iii) the production of a video on the making of an ice storm and relevance to extreme events and climate change; and (iv) undergraduate, graduate and post-doctoral training.