Forest ecosystems will be affected directly and indirectly by a changing climate over the 21st century. This assessment evaluates the vulnerability of 11 forest ecosystems in the Mid-Atlantic region (Pennsylvania, New Jersey, Delaware, eastern Maryland, and southern New York) under a range of future climates. The report synthesizes and summarizes information on the contemporary landscape, provides information on past climate trends, and describes a range of projected future climates. This information is used to parameterize and run multiple forest impact models, which provides a range of potential tree responses to climate. Finally, these results were brought before two multidisciplinary panels of scientists and land managers familiar with the forests of this region to assess ecosystem vulnerability through a formal consensus-based expert elicitation process.