The forests in northern Michigan will be affected directly and indirectly by changing climate during the 21st century. This assessment evaluates the vulnerability of forest ecosystems in the eastern Upper Peninsula and northern Lower Peninsula of Michigan under a range of future climates. We synthesized and summarized information on the contemporary landscape, provided information on past climate trends, and described a range of projected future climates. This information was used to parameterize and run multiple vegetation impact models, which provided a range of potential vegetative responses to climate. Finally, we brought these results before a multidisciplinary panel of scientists and land managers familiar with Michigan forests to assess ecosystem vulnerability through a formal consensus-based expert elicitation process. The summary of the contemporary landscape identifies major forest trends and stressors currently threatening forests in the region. Observed trends in climate over the past century reveal that precipitation increased in the area, particularly in summer and fall, and that daily maximum temperatures increased, particularly in winter. Projected climate trends for the next 100 years using downscaled global climate model data indicate a potential increase in mean annual temperature of 2.2 to 8.1 °F for the assessment area. Projections for precipitation indicate an increase in winter and spring precipitation, and summer and fall precipitation projections vary by scenario. We identified potential impacts on forests by incorporating these climate projections into three forest impact models (Tree Atlas, LANDIS-II, and PnET-CN). Model projections suggest that northern boreal species such as black spruce and paper birch may fare worse under future conditions, but other species such as American elm and white oak may benefit from projected changes in climate. Published literature on climate impacts related to wildfire, invasive species, and diseases also contributed to the overall determination of climate change vulnerability. We assessed vulnerability for nine forest communities in the assessment area, which were a combination of U.S. Department of Agriculture, Forest Service Forest Inventory and Analysis program forest types and Michigan Natural Features Inventory natural communities. The basic assessment was conducted through a formal elicitation process of 27 science and management experts from across the state, who considered vulnerability both in terms of potential impacts on a system and in terms of the system's adaptive capacity. Upland spruce-fir, jack pine, lowland conifers, and red pine-white pine forest communities were determined to be the most vulnerable. Barrens and lowland/riparian hardwood communities were perceived as less vulnerable to projected changes in climate. These projected changes in climate and the associated impacts and vulnerabilities will have important implications for economically valuable timber species, forest-dependent wildlife and plants, recreation, and long-range p...

Forest ecosystems across the Northwoods will face direct and indirect impacts from a changing climate over the 21st century. This assessment evaluates the vulnerability of forest ecosystems in the Laurentian Mixed Forest Province of northern Wisconsin and western Upper Michigan under a range of future climates. We synthesized and summarized information on the contemporary landscape, provided information on past climate trends, and described a range of projected future climates. This information was used to parameterize and run multiple vegetation impact models, which provided a range of potential vegetative responses to climate. Finally, we brought these results before a multidisciplinary panel of scientists and land managers familiar with the forests of this region to assess ecosystem vulnerability through a formal consensus-based expert elicitation process.The summary of the contemporary landscape identifies major forest trends and stressors currently threatening forests in the region. Observed trends in climate over the past century reveal that precipitation increased in the area, particularly in summer and fall, and that daily maximum temperatures increased, particularly in winter. Projected climate trends for the next 100 years using downscaled global climate model data indicate a potential increase in mean annual temperature of 2 to 9 °F for the assessment area. Projections for precipitation indicate an increase in winter and spring precipitation, and summer and fall precipitation projections vary by scenario. We identified potential impacts on forests by incorporating these future climate projections into three forest impact models (Tree Atlas, LANDIS-II, and PnET-CN). Model projections suggest that northern boreal species such as black spruce, quaking aspen, and paper birch may fare worse under future conditions, but other species may benefit from projected changes in climate. Published literature on climate impacts related to wildfire, invasive species, and forest pests and diseases also contributed to the overall determination of climate change vulnerability. We assessed vulnerability for nine forest communities in the assessment area. The assessment was conducted through a formal elicitation process of 19 science and management experts from across the area, who considered vulnerability in terms of the potential impacts and the adaptive capacity for an individual community. Upland spruce-fir, lowland conifers, aspen-birch, lowland-riparian hardwoods, and red pine forests were determined to be the most vulnerable ecosystems. White pine and oak forests were perceived as less vulnerable to projected changes in climate. These projected changes in climate and the associated impacts and vulnerabilities will have important implications for economically valuable timber species, forestdependent wildlife and plants, recreation, and long-term natural resource planning. ABSTRACT Cover PhotoLake of the Clouds in western Upper Michigan. Photo by Scott Pearson, used with permission.

Climate change is having important effects on forest ecosystems, presenting a challenge for natural resource professionals to reduce climate-associated impacts while still achieving diverse management objectives. Regional projections of climate change and forest response are becoming more readily available, but managers are still searching for practical ways to apply this information. We propose that commonly collected forest inventory data be used in conjunction with species distribution models to better understand the potential response of forests to climate change and inform management at the site level. In this article, we propose a new climate risk metric that incorporates stand-level forest inventory data with projections of tree species habitat from the Climate Change Tree Atlas. This climate risk metric can serve as a starting point for managers to consider how forests may be altered by climate change. We also describe two examples of how this metric was used in real-world management situations.