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Because of the Gap Analysis Program, the Oregon Natural Heritage Program has developed and is constantly improving three major types of vegetation or land cover maps in GIS. While much of the work has focused on existing vegetation and land cover, ORNHP also has developed statewide and regional historic or presettlement vegetation coverages, and is working on the development of a potential natural vegetation coverage. These are described below.
Historic or Presettlement Land Cover
The Oregon Natural Heritage Program worked with the Defenders of Wildlife and Jim Strittholt to develop the first statewide, historic vegetation coverage for Oregon. It was compiled from a number of sources.
The most important sources were:
- Forest coverage developed by H.J. Andrews in the 1930s obtained from the OSU/USFS Forest Sciences Lab
- 1:24,000 historic vegetation coverages of the Willamette Valley, the Umpqua Valley, and the Oregon coast developed by the Oregon Natural Heritage Program
- Eastern Oregon rangeland cover developed by the Oregon Natural Heritage Program
This coverage was updated for the gap final report in 1999 at an 1:100,000 scale, to allow for a comparison between the existing and historic vegetation and wildlife habitat losses. This coverage is available on-line. An image of the historic wildlife habitats can be found below.
ORNHP is continuing to work on the completion of the 1:24,000 historic vegetation coverages based on the General Land Office surveyor’s notes. Currently funding is available to complete the Rogue Valley, and funding is being sought for the Grand Ronde and Wallowa River Valleys.
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