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Because of the Gap Analysis Program, the Oregon Natural Heritage Information Center 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, ORNHIC also has developed statewide and regional historical or "presettlement" vegetation coverages, and is working on the development of a potential natural vegetation coverage. These are described below.
GAP Historical or "Presettlement" Land Cover
The Oregon Natural Heritage Information Center worked with the Defenders of Wildlife and Jim Strittholt to develop the first statewide, GAP historical 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 coverages created by ORNHIC based on General Land Office (GLO) survey data, crosswalked to GAP land cover types
- Eastern Oregon rangeland cover developed by the Oregon Natural Heritage Information Center
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 historical vegetation and wildlife habitat losses. This coverage is available online. An image of the historical wildlife habitats can be found below.
For ORNHIC's historical vegetation maps based on original GLO survey data, see our General Land Office Surveys page.
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