Workshop: Using Elevational Treelines to Predict Climate Change Effects on the Future Size and Distribution of Mountain Forests; University of Idaho, August 4-7, 2015

山脉覆盖了地球陆地面积的大部分（约24%），居住着约20%的世界人口，为近一半的世界人口提供关键的生态系统服务，并经常形成国家之间的边界。大多数这些山地生态系统都覆盖着森林，这些森林是重要的，往往是关键的服务，如水的储存和供应，商业建筑和供暖产品，娱乐和旅游，所有这些都表明了在未来全球变化下了解其未来可持续性的重要需要。这次讲习班将汇集来自世界各地的专家，试图综合观察到的森林边界的机械原因。具体而言，会议的重点将放在生态生理适应及其与遗传机制的联系上。会议将在一个为对科学感兴趣，但在科学、技术、工程、数学领域缺乏代表性的高中生提供暑期体验的设施举行。讲习班将允许在实地站参加暑期班的学生直接参加。会议的智识方法将是产生关于山地森林海拔分布未来可能变化的预测能力。树线的上下边界确定了这种分布格局，并根据目前大气二氧化碳上升和全球变暖的情景预测了未来的变化。这些森林的边界和规模的这种变化可能会极大地改变许多生态系统的服务，包括积雪的积累和对农业和市政的供水。此外，对这些山林的未来大小和分布的预期变化的早期估计可以大大有利于未来的森林管理政策。讲习班将汇集具有公认专业知识的全球研究人员，以了解非生物和生物环境如何机械地影响山地森林的上下边界（树线）的高度，从而提供一种估计全球山地地带性森林带总宽度未来变化的方法。山地森林边界以前被认为是气候变化对全球生态系统影响的风向标。然而，关于驱动目前全球树木线观测到的海拔高度的具体机制，几乎没有达成共识。目前关于生理限制存在矛盾的观点，包括基本的代谢过程，如光合作用捕获与碳的代谢过程，以及可能限制其中任何一种的非生物/生物因素。此外，大多数关于驱动树线高度的机制的证据来自于对成熟树木的测量，而不是在死亡率通常是所有生命阶段中最高的早期建立阶段。更具体地说，树木线上的树木繁殖一直是一个被忽视的重点领域，包括新幼苗建立是一个关键的瓶颈生命阶段的想法。此外，研讨会参与者将讨论碳处理（碳汇）限制而不是碳获取（碳源）限制应该作为理解树线上新幼苗建立的一个缺失但至关重要的组成部分。最终目标将是编写一份综合手稿，提交一份有广泛读者群的国际期刊发表。另一个主要目标是通过研讨会场地（爱达荷大学麦考尔场站）的K-12课程、参与的研究生和助理教授以及主要的社交媒体渠道，让尽可能多的外部研讨会参与者进行互动。

Mountains cover a major portion of the Earth's land area (approximately 24%), house approximately 20% of the world's population, provide critical ecosystem services to nearly half of the world population, and often form the boundaries between countries. Most of these mountain ecosystems are covered with tree forests that are key to important, often critical, services such as water storage and supply, commercial building and heating products, recreation and tourism, all of which dictate an important need for understanding their future sustainability under future global changes. This workshop will bring together experts from around the globe in an attempt to synthesize the mechanistic causes of observed forest boundaries. Specifically, emphasis at the meeting will be placed on ecophysiological adaptations and their linkages to genetic mechanisms. The meeting will be held at a facility that offers summer experiences to high school students interested in science but underrepresented in the fields of science, technology, engineering, and mathematics. The workshop will allow direct access by students attending summer classes at the field station. The intellectual approach of the meeting will be to generate predictive capabilities about potential future shifts in the elevational distributions of mountain forests. The upper and lower treeline boundaries define this distribution pattern, and future shifts have been projected based on current scenarios of rising atmospheric carbon dioxide and global warming. Such shifts in the boundaries and, thus, size of these forests could dramatically alter a host of ecosystem services, including snowpack accumulation and water supply to agriculture and municipalities. Moreover, future forest management policies could benefit significantly from early estimates of the anticipated changes in the future size and distribution of these mountain forests. The workshop will bring together global researchers with recognized expertise for understanding how the abiotic and biotic environment influences mechanistically the elevation of the lower and upper boundaries (treelines) of mountain forests and, thus, a method for estimating future changes in the total breadth of the zonal forest bands found on mountains across the globe. Mountain forest boundaries have been recognized previously as a bellwether of climate change impacts on global ecosystems. Yet, little consensus exists regarding the specific mechanisms driving the elevations currently observed for treelines across the globe. Conflicting ideas currently exist concerning physiological constraints, including fundamental metabolic processes such as the photosynthetic capture versus the metabolic processing of carbon, plus the abiotic/biotic factors that may be limiting either. Moreover, most of the evidence for mechanisms driving treeline elevations comes from measurements on mature trees, rather than the early establishment stages when mortality is often the highest of all life stages. More specifically forest tree reproduction at treelines has been a neglected area of focus, including the idea that new seedling establishment is a critical, bottleneck life stage. Also, workshop participants will address the idea that carbon processing (sink) instead of carbon acquisition (source) limitations should be included as a missing, yet crucial, component for understanding new seedling establishment at treeline. The ultimate objective will be the formulation of a synthesis manuscript to be submitted for publication in an internationally-refereed journal with a broad readership. Another primary objective will be to involve the interaction of as many external workshop participants as possible via the K-12 program at the workshop venue (McCall Field Station, Univ Idaho), participating graduate students and Assistant Professors, and major social media outlets.