National Forest Map and GIS Data

Caitlin Dempsey


What areas of the United States contain the densest amount of woody biomass?  Showing the conterminous United States, the intensity of biomass (a measure of the amount of organic carbon—stored in the trunks, limbs, and leaves of trees) has been mapped out with a baseline year of 2000.  The darkest green areas are the locations with the most dense and tallest tree growth.  The coastal Pacific Northwest contains the highest density of biomass within the country.

The map was created from data developed by Josef Kellndorfer and Wayne Walker of the Woods Hole Research Center (WHRC) who worked with the USGS and the US Forest Service over a six year period. The project was funded by NASA’s Terrestrial Ecology Program with additional support from the Landscape Fire and Resource Management Planning Tools Project (LANDFIRE).  To compile the data, the 48 states were divided into 66 mapping zones.  Data from a variety of sources was obtained for this enormous tree mapping endeavor which include SRTM data, National Land Cover Database, and over 5 million trees from the US Forest Service’s Forest Inventory and Analysis program:

Development of the dataset is based on an empirical modeling approach that combines USDA Forest Service Forest Inventory and Analysis (FIA) data with high-resolution InSAR data acquired from the 2000 Shuttle Radar Topography Mission (SRTM) and optical remote sensing data acquired from the Landsat ETM+ sensor. Three-season Landsat ETM+ data were systematically compiled by the Multi-Resolution Land Characteristics Consortium (MRLC) between 1999 and 2002 for the entire U.S. and were the foundation for development of both the USGS National Land Cover Dataset 2001 (NLCD 2001) and the LANDFIRE project. Products from both the NLCD 2001 (landcover and canopy density) and LANDFIRE (existing vegetation type) projects as well as topographic information from the USGS National Elevation Dataset (NED) are used within the NBCD 2000 project as spatial predictor layers for canopy height and biomass estimation. Forest survey data provided by the USDA Forest Service FIA program were made available to the project under a national Memorandum of Understanding. The response variables (canopy height and biomass) used in model development and validation were derived from the FIA database. Production of the NLCD 2001 and LANDFIRE projects was based on a mapping zone approach in which the conterminous U.S. is split into 66 ecoregionally distinct mapping zones. This approach was also adopted by the NBCD 2000 project. Data products are provided on a zone-by-zone basis.

Aboveground Woody Biomass Map by Josef Kellndorfer and Wayne Walker.
Aboveground Woody Biomass Data by Josef Kellndorfer and Wayne Walker. Map from NASA, 2011.

The resolution of the GIS data at 30 meters is amazing considering the data coverage area.  In the sample images below, an area of detail taken from the Pacific Northwest shows the pattern of forest logging down to the individual plots.

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Pacific Northwest Forest Area.
Pacific Northwest Forest Area.
Detail of the Pacific Northwest showing individual forest logging plots.
Detail of the Pacific Northwest showing individual forest logging plots.

All map images are courtesy of NASA and were created by Robert Simmon.  The GIS data set for this map is available for free from the Woods Hole Research Center by visiting National Biomass and Carbon Dataset (NBCD).  Those requesting access to the data are asked to supply their name, email, and affiliation.

(Via @mrgeog)
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About the author
Caitlin Dempsey
Caitlin Dempsey is the editor of Geography Realm and holds a master's degree in Geography from UCLA as well as a Master of Library and Information Science (MLIS) from SJSU.