However, such progress is possible and desirable. One exploratory attempt to assess the human role in forest function has been made in a project on the New York City Metropolitan region. The metropolitan area encompasses some of the densest and most highly developed land in the U.S., as well as open, thinly populated farming and forested landscapes. In other words it provides a wide range of conditions in which to discover the relationships between human population, development and land use patterns. Sample areas were established in several closed canopy forests in the urbanized Bronx, suburbanized areas of Westchester County, New York, and rural Litchfield County, Connecticut.
All sites show the same bedrock and soil types.
The forests differed in key ecosystem parameters, such as litter decay and nitrogen mineralization rates. Several readily available variables were assembled for cells of 4x4 km centered on the forest patches. Of the variables examined, traffic volume explained the greatest proportion of the variation among forest processes. Population density, and road density also explained large amounts of the difference. However the fact that traffic volume can be more directly linked to the input of nitrogen in the nearby atmosphere suggests that it is not only the statistically best but also the ecologically most relevant variable.