Human land use has been recognized as the single biggest driver of ecological change in the deciduous forests of eastern North America. We examine how human land use has shaped the forests of a topographically complex section of the Western Allegheny plateau over the last 90 years. Historical aerial photographs were used to describe landuse change around Athens, Ohio, with respect to the physical environment and preexisting landscape structure. Multivariate analyses suggested landscape metrics that influenced the decision to abandon a given plot of land, and how environmental gradients govern these decisions. Human land use was compared with key environmental factors such as landscape position, soil composition, and forest age. We expected that modern forests are a result of selective agricultural abandonment, driven by specific environmental and geographic factors that are important at the scale of the individual farm.
Results/Conclusions
Since 1940, the area of forest patches has increased dramatically and edge distance has declined each decade until ca. 2000, at which point forest cover stabilized. This gain in forest was accompanied by a comparable loss in agricultural land, consistent with large-scale agricultural abandonment. Forest soils tend to be shallow with high bulk density and high mineral fraction, suggesting that most forest fragments are situated on land of marginal agricultural value.
Transition to forest was governed by processes at multiple spatial scales, and the strength of these factors in driving land use decisions varies temporally. At a coarse scale, abandonment varied on an East-West gradient; at a finer scale abandonment was more likely far from existing buildings and close to other forested sites – the latter becoming more influential through time. Our data paint a picture of a complex landscape whose patchwork mosaic of forests, agricultural land, and built environments are governed by human land use decisions at both regional and site scales. Land use decisions are in turn driven by economic transition from small-scale agriculture to a site-independent service economy in the mid- and late 20th century.