Dynamic Models of Land Use Change

Land Use Change in the Northeastern United States

In a major effort to understand the dynamics of land use change and its impacts on the natural resources of the northeast, the Yale FES Global Institute of Sustainable Forestry and SUNY College of Environmental Science and Forestry have completed three studies covering four regions in the northeast. These studies have been led by Mary Tyrrell (Yale GISF) and Myrna Hall (SUNY ESF) in collaboration with many other scientists and institutions.

Forests in the northeast are increasingly under threat from urban sprawl and other unplanned development. Nationwide, eighty percent of new housing construction is occurring on the rural landscape. The challenge is increasingly one of keeping forests as forests—preventing their permanent loss to development or from being fragmented into such small parcels that sustainable management is no longer feasible. Our research focused on detecting the patterns and trajectories of the cumulative changes causing forest fragmentation and permanent loss of forestland in the region.

The core of this work is the application of a dynamic land use simulation model, developed by Systems Ecologist Charles Hall and graduate students at SUNY ESF, to the problem of loss and fragmentation of forestland due to unplanned growth and sprawl. This model, GEOMOD, predicts the rate and spatial pattern of land conversion, particularly that which is anthropogenically-derived. GEOMOD is extraordinarily effective in helping people understand the dynamics of land use change, see where forests are most at risk of fragmentation and conversion to development, visualize future conditions, and plan strategic approaches to the mitigation of harmful trends. Knowing how, where, and why those changes are likely to occur can be a powerful tool for conservation organizations, community leaders, and citizens.

Using classified satellite imagery, parcelization analysis, land owner surveys, on-the-ground measurements, GEOMOD, we have assessed the impacts of sprawling development on the forests and farmlands of New England's Thames Watershed, New York's Catskill/Delaware watersheds, and the Highlands of Connecticut and Pennsylvania.  We tested the influence of a variety of biological, geological, sociological, demographic, economic, and physical factors on both where and how much development has occurred.  Future change was predicted based on this empirical analysis.  Our findings reveal that the rate of forest conversion is low (less than 0.5% per year), however the impacts are significant as the remaining forests are more fragmented.  We found that forestland that has been parcelized is 1.5 times more likely to be converted to other uses than land that has not been divided.  In some of these regions, active farmland is being lost to mostly residential development at a rate of between 1% and 2% per year.

The “Highlands Regional Study: Connecticut and Pennsylvania Updates” report was completed in 2008.  The 240-page summary is available online, as is the 368-page technical report.  These reports document the results of an extensive study of land use change and its impacts on forests and farmlands of the region, funded by the US Forest Service Northeastern Area State & Private Forestry. Other collaborators were the Regional Plan Association, the University of Connecticut, and the Appalachian Mountain Club. 

The Highlands region, which stretches from northwestern Connecticut to the rolling hills of Pennsylvania between Philadelphia and Harrisburg is under tremendous pressure from development sprawling out of New York City, Philadelphia, and even the Washington, DC metropolitan area.  The study was designed to provide a scientific understanding of the dynamics and trends of land use change, demographics, and development in the Connecticut and Pennsylvania Highlands, and of how these changes are affecting the forest and agricultural resources of the region.  A summary of the results, along with a water resources analysis conducted by the USGS, can be found online.

The first study, of the Thames Watershed in Connecticut and Catskill/Delaware watersheds in New York, was funded by the US Forest Service, Cooperative Forestry.  These largely forested places are under tremendous pressure from development and the sprawling metropolitan areas of New York City, Boston, Hartford and Providence. As the largest unfiltered surface water supply in the country, the New York City Watershed is extremely vulnerable to potential changes in land use. Protecting the remaining forested landscape is a high priority for both the local communities and the urban population of New York City. The Thames River Watershed, in northeastern Connecticut and south-central Massachusetts, known as the “Last Green Valley” between New York and Boston, is home to the Quinebaug-Shetucket National Heritage Corridor, the Norcross Wildlife Sanctuary and the Yale Myers Forest. The smallest towns in this valley have experienced an average population growth of 17% from 1990 to 2000.

The report, “Dynamic Models of Land Use Change in Northeastern USA: Developing Tools, Techniques, and Talents for Effective Conservation Action”, highlights the problem of increasing fragmentation across the landscape of one of Connecticut’s most forested areas, the “quiet corner” of northeastern Connecticut.

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