Detailed assessment of the decline of core forest in the Conterminous United StatesThis article is part of a larger document. View the larger document here.
Forest loss and fragmentation of the remainder threaten the sustainability of many ecological attributes and processes that depend on extensive forest cover. The direct loss of intact forest is an obvious threat; less obvious are the indirect threats posed by isolation and edge effects, which encompass a wide range of biotic and abiotic inuences on remnant forest (Forman and Alexander 1998, Harper and others 2005, Laurance 2008, Murcia 1995, Ries and others 2004). Because fragmentation is a spatial process, monitoring the threats posed by forest fragmentation necessarily involves analysis of forest maps. The forest maps from the National Land Cover Database (NLCD) have proven useful for synoptic analyses because they provide consistent and complete coverage for the Nation. However, those synoptic analyses provide no details about the forest types or ownerships that are being fragmented. That information is important when considering conservation and restoration alternatives such as where to add or remove forest cover and whether the effort should be a public or private concern. A recent analysis of forest fragmentation trends using NLCD maps from 2001 and 2006 documented a decline in relatively intact forest in the conterminous United States (Riitters and Wickham 2012). The objective of this report is to reevaluate that decline in relation to forest types and ownerships by incorporating in situ data from the Forest Inventory and Analysis (FIA) databases.