Vegetation patches larger than 1/2 acre. Based on information from reference data sources including 6" resolution aerial photos, Parks and Recreation natural area assessments, and vegetation surveys along the banks of the Willamette and Columbia rivers. Vegetation patches area classified as forest, woodland, shrubland, or herbaceous. The mapping area includes all land within the City of Portland and the unincorporated parts of Multnomah County that are administered by the City of Portland.
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Purpose: For analyzing vegetation within Portland's riparian and upland areas. Developed as an input to the Bureau of Planning's GIS model for identifying significant natural resources.
The key goals of the vegetation mapping project were
1) refine the location of vegetation "patches" of areas previously mapped by Metro;
2) incorporate vegetation maps generated by other agencies such as Portland Parks and Recreation and the Portland Bureau of Environmental Services and refine and improve that information where necessary;
3) map vegetation patches meeting Portland’s criteria for inclusion in the natural resource inventory a 1/2 acre minimum patch size versus the 1 to 2 acre patch size used by Metro for the regional dataset;
4) map all vegetation within a 1/4 mile of a surface stream, wetland, or regionally significant habitat resources included in Metro’s inventory;
5) classify the vegetation into four NVCS classes: forest, woodland, shrubland, and herbaceous;
6) further classify vegetation as either "natural/semi-natural" or "cultivated"; and
7) update, refine and improve the vegetation data annually as new aerial photos become available.
Update Frequency: As needed
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