Five Anthropogenic Factors That Will Radically Alter Forest Conditions and Management Needs in the Northern United States

The Northern United States includes the 20 states bounded by Maine, Maryland, Missouri, and Minnesota. With 70 million ha of forestland and 124 million people, it is the most densely forested (42% of land area) and most densely populated (74 people/km^sup 2^) quadrant of the United States. Three recent, large-scale, multiresource assessments of forest conditions provide insight about trends and issues in the North, and collectively these and other supporting documents highlight factors that will be extraordinarily influential in large-scale northern forest management needs over the next 50 years. This review article discusses five of those factors: (1) northern forests lack age-class diversity and will uniformly grow old without management interventions or natural disturbances, (2) the area of forestland in the North will decrease as a consequence of expanding urban areas, (3) invasive species will alter forest density, diversity, and function, (4) management intensity for timber is low in northern forests and likely to remain so, and (5) management for nontimber objectives will gain relevance but will be challenging to implement. Suggested actions to address these factors include the following: develop quantifiable state and regional goals for forest diversity, understand the spatial and structural impacts of urban expansion on forests, develop symbiotic relationships among forest owners, forest managers, forest industry and the other stakeholders to support contemporary conservation goals, and work to understand the many dimensions of forest change. In the next several decades, climate change seems unlikely to overwhelm or negate any of the five factors discussed in this article; rather it will add another complicating dimension.