Figure 7

2007 U.S. county forestion coverage (Percent). County forest coverage was obtained from the United States Department of Agriculture (USDA)[11]. Total county area was obtained from the Census Bureau[12]. Percentages of forest coverage were calculated by dividing the forest coverage area by county area (times 100%). The definition of forest coverage here is restricted to agriculture woodland, which means land supporting trees capable of producing timber or other wood products, including but not limited to logs, lumber, posts, and firewood. This data are updated by the USDA every five years. However, the 2012 data is not available yet; hence, the 2007 data were used to generate the graph.