Urbanization in the US: land use trends, impacts on forest area, projections, and policy considerations

Abstract

Since World War II, socio-economic drivers of US urbanization such as population totals and personal income levels have increased substantially. Human land use is the primary force driving changes in forest ecosystem attributes including forest area, which is the focus of this paper. The percentage of the US population residing in urban areas is higher than that in India. In the last few decades, the primary reason behind conversion of large areas of US forests is for urban and development uses. Since 1990, land use changes in the US that have affected forests have been heavily concentrated in the South. Nationwide, more than 60% of US housing units built during the 1990s were constructed on or near areas of wildland vegetation. Between 1982 and 1997, the US population grew by 17%, while the urbanized area rose by 47%. The amount of land area per additional individual dedicated to new housing has almost doubled in the last 20 years. About 18 million hectares of private forest are projected to experience housing density increases by 2030, with the most heavily impacted watersheds occurring in the East. The US population is projected to grow by more than 120 million (40%) by 2050. Deforestation associated with this growth is projected to exceed 20 million hectares (13% of the existing private forest area). Fragmentation of remaining forests is also projected, and is expected to be concentrated in distinct sub-regions, namely, the US South, that include urbanizing areas and areas close to interstate highway corridors.