9524078 Reich Forest Change in a Boreal Transition Region: Productivity, Nutrient Cycling and Biodiversity at Multiple Scales. The actions of human society have profound impacts on boreal forests worldwide. Land use such as timber harvesting, climate, elevated carbon dioxide levels, and altered fire regimes all contribute to changes in the composition (species make-up), function and biodiversity of boreal forest ecosystems. This project will assess how forests are changing, and why, in relation to key regional and global factors such as logging, fire, elevated carbon dioxide, and climate. Why is it important that we better understand what those impacts are at present, and may be in the future? First, boreal forests contribute to the economic well being of the USA and globally as a source of fiber for the forest products industry. Second, boreal forests play an important role in global carbon cycles, and thus influence global carbon dioxide levels. Third, boreal forests represent the largest intact forest biome on the planet and house a better balanced flora and fauna than any other forest biome. This last point has importance economically as well as ecologically. Regions with major boreal forest coverage are used by native peoples and support a growing recreational industry that depends on wildlife, clean water, and natural beauty. Changes that alter the productivity or long-term soil fertility of boreal forests, or that alter the plant and animal diversity of such regions, are likely occurring. However, a critical question is whether they are altering such processes in ways that are beneficial, neutral, or detrimental to our long-term goals for such regions, and equally critical is the question of the magnitude of such changes, both on a forest stand basis and for a forested region as a whole. The answers to such questions will help us in two main ways. First they aid in our overall assessment of forest response to global atmospheric change and its associated climate impacts. Secon d, they enable better design of timber harvesting (and other management options), with respect to scope, type, timing, and landscape configuration. Just how much timber harvesting can occur, and how and where, with minimal detriment to the environment, is a very difficult question (and usually quite controversial) but one that is important to society .