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

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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.