Forest Plan Implementation
Procedures and Tools
GIS Layers for Cumulative Effects Analysis
In order to quantitatively consider cumulative harvest and cumulative road development in the effects analyses for the 2008 Forest Plan Amendment Environmental Impact Statement, new GIS layers were developed for vegetation and roads on non-NFS lands. These new layers are called "nonnfs_veg" and "non_nf_rds" and their development and use are described below.
Vegetation on Non-NFS Lands
Development of a vegetation layer for non-NFS lands was conducted by combining data from a number of sources. The base vegetation layer for non-NFS lands was derived from a layer developed for a conservation assessment completed by Audubon Alaska and The Nature Conservancy (Albert and Schoen 2007). This layer, which covers all of Southeast Alaska, provides a reasonably accurate representation of vegetation. It was based on the Tongass Size-Density Model mapping, augmented with timber inventory data from Haines State Forest and with classified Landsat Multi-spectral Scanner imagery from the Interim Landcover Mapping Program of the U.S. Geological Survey and 1997 aerial photography.
To more accurately portray the boundaries of past harvest, this layer was refined with information from GIS layers provided by Sealaska Regional Corporation, the State of Alaska, and aerial photography. The resultant combined layer is called "nonnfs_veg" and it covers all of the non-NFS lands in Southeast Alaska. A data dictionary for this layer provides definitions of the primary field codes, including the vegetation description codes.
Roads on Non-NFS Lands
Development of an existing roads layer for non-NFS lands was also produced by combining data from a number of sources. The Tongass GIS library layers contain many roads on non-NFS lands. These were supplemented with roads provided by Sealaska Regional Corporation, the State of Alaska, other available GIS layers (e.g., ESRI's StreetMap for urban/rural areas), and aerial photo interpretation. The resultant combined layer is called "non_nf_rds" and it covers all of the non-NFS lands in Southeast Alaska. A data dictionary for this layer provides definitions of the primary field codes.