A digital map of the forests of Oregon and Washington was obtained from Janet Ohman of the PNW Forest and Research Station in Corvallis. No metadata is available with the exception of a list of types. Based on the detail in the cover, it appears to have been developed at an approximately 1:100,000 scale. The map was digitized from original surveys of USFS crews headed by H.J. Andrews in the 1930s, presumably from WPA. The original cover was mapped to forest type, with a secondary classification for young forests. Recent timber harvest areas (clear-cuts) and burned forest were also mapped. Metadata for the original dataset follows:
Export Name: BVBH1936
Theme Name: VEGETATION - HISTORIC OR/WA 1936
Theme Id: 425 Theme Abbreviation: VEGH1936 Export Name: BVBH1936
Disclaimer: The ICBEMP cannot assure the reliability or suitability of this information for a particular purpose. Original data was compiled from various sources. Spatial information may not meet National Map Accuracy Standards. This information may be updated without notification. Project Name: ICBEMP
Theme Description: Historical Vegetation of Oregon and Washington Coverage Extent: OREGON AND WASHINGTON
Source: US FOREST SERVICE Last Update: 14-JAN-95 Feature Type: POLYGON Distribution Limit: NONE Theme Keywords: VEGETATION, HISTORICAL, ANDREWS Data Resolution: 1:500000 Projection: ICBEMP ALBERS File Pathname: /emp/crbv/crb/veg/hveg36 Comments: Captured from the 1936-37 Historical Vegetation Maps from HJ Andrews and Cowlins.
SOURCE INFORMATION Source System: LINE TRACE FOR X WINDOWS Source Scale: 1:500000 Source Projection: ALBERS Capture Method: Digital capture via manuscript then scanning.
CUSTODIAN INFORMATION Contact Org: USFS Contact Person: ANDY WILSON Contact Phone: Email Id: Contact Address: ICBEMP SPATIAL ANALYSIS TEAM 333 SW FIRST PORTLAND, OR 97204
PROCESSING INFORMATION Theme Generation: Lineage: Data Transfer: Procedure Contact: ANDY WILSON
ATTRIBUTE INFORMATION Label Type: ARC Table Name: HVEG36.PAT Length: 3 Attribute Name: HVEG36_CD Attribute Value Type: C
Attribute Value Description 1 NON-FOREST 2 AGRICULTURAL ZONE 3 SUBALPINE AND NONCOMMERCIAL 4 LODGEPOLE PINE 5 JUNIPER 6 DOUGLAS FIR;OLD GROWTH 7 DOUGLAS FIR;LARGE SECOND GROWTH 8 DOUGLAS FIR;SMALL SECOND GROWTH 9 DOUGLAS FIR;SEEDLING,SAPLING,POLE 10 SPRUCE-HEMLOCK;LARGE 11 SPRUCE-HEMLOCK-CEDAR;SMALL 12 CEDAR-REDWOOD;LARGE 13 PONDEROSA PINE:SMALL 14 PURE PONDEROSA PINE:LARGE 15 PONDEROSA PINE,SMALL 16 PONDEROSA PINE;SEEDLING-SAPLING-POLE 17 PINE MIX;LARGE 18 PINE MIX;SMALL 19 BALSAM FIR-MT HEM-UPPER SLOPE TYPES;LARGE 19W WESTERN WHITE PINE;LARGE 20 BALSAM FIR-MT HEM-UPPER SLOPE TYPES;SMALL 20W WESTERN WHITE PINE;SMALL 21 HARDWOOD,ALDER-ASH-MAPLE 22 HARDWOOD,OAK-MADRONE 23 RECENT CUTOVER 24 NON-RESTOCKED CUTOVER 25 DEFORESTED BURNS W WATER
Label Type: ARC Table Name: HVEG36.PAT Length: 50 Attribute Name: HVEG36_NAME Attribute Value Type: C
Before the cover was used, areas classified as young were re-classed to the forest type (ie young Douglas-fir became Douglas-fir). Polygons labeled as recent timber harvest areas and burned forest were individually re-classed, based on adjacent forest communities, elevation, and location by Jimmy Kagan and Jim Stritholt. The original cover also included forest types named "Balsam fir" and "non-commercial forests". These types were split into four separate forest communities by Jimmy Kagan, based on the locations of the polygons, as described below.
Reclasses were in the following steps: For non-forest land in the west-side interior valleys and in southwestern Oregon, data from the Valley Historic Vegetation coverage was patched in. Non-forest Polygons along the Pacific coast and along the Columbia River were reclassed as either wetlands, dunes, or prairies. All non-commercial forest types were reclassified as subalpine fir except in the following cases. 1. Klamath Mountain ecoregion non-commercial forests were classified as Jeffery Pine. In coastal areas, Lodgepole Pine was reclassified as Shore Pine. Juniper was left as depicted. 2. All Douglas-fir age classifications were merged into one classification. 3. Both Spruce-hemlock classes were merged into one. 4. Cedar-Redwood polygons in Curry County (seven small polygons and two large polygons) were reclassified as Coast Redwoods. Other Cedar-Redwood polygons in the Siskiyou Mountains were classified as Port Orford Cedar. The remaining Cedar-Redwood areas were classified as Western Red Cedar. 5. All ponderosa pine were merged into one classification. 6. All mixed pine classes were merged into one. 7. Balsam Firs, Mountain Hemlock and upper slope types in the Klamath Mountains and southern Cascades were classified as Shasta fir-White fir. All other Balsam Firs, Mountain Hemlock and upper slope types were classified as Pacific Silver Fir-Mountain Hemlock. 8. Hardwoods (alder, ash, willow) were merged with 'bottomland hardwoods/Gallery forests' from the Valley Historic Vegetation coverage to create a Bottomland Hardwoods classification. Some areas of this were added in the Grande Ronde valley. 9. Oak and Mandrone forests were renamed Oak-Mandrone. 10. Recent cut-over, nonforested cut-overs, and deforested burns were reclassified based on adjacent vegetation and personal knowledge.
A digital map of current vegetation for southeastern Oregon was originally created from BLM coverages, SSURGO data, and Gap data when no other data source was available, as part of a different project. Specific metadata for this coverage can be obtained from Claudine Tobalske. The coverage was updated to reflect plausible presettlement vegetation patterns. The following vegetation and land-use types were removed or modified: crested wheatgrass (Agropyron cristatum); cheatgrass (Bromus tectorum); agriculture; recent burns; recent cuts; urban; reservoirs; mines and quarries; western juniper woodland; and forest.
For Wasco, Sherman, Gilliam, Morrow, Umatilla, Union, Baker, and part of Jefferson and Lake counties, land cover polygons were obtained from from the Soil Survey Geographic (SSURGO) database. The 1:24,000 soil polygons came with associated databases for climax/historical plant composition and climax/historical tree cover. Because SSURGO data present potential vegetation based on soil types, they were used to replace post-settlement vegetation and land-use types. Where SSURGO data were not available, these types were replaced with potential pre-settlement vegetation based on the composition of adjacent polygons, and the presence of rivers and streams (for riparian areas and bottomlands). Recent burns and regenerating young forests were reverted to forest. In addition, polygons from the GLO survey were incorporated in Umatilla county (prickly pear grassland, tufted hairgrass). SSURGO polygons were also recoded throughout the area to reflect the presence of riparian vegetation (with on-screen digitizing when necessary).
Location of western juniper patches was checked against their location in the H.J. Andrews map. Those polygons that were not labeled juniper in the H.J. Andrews map were recoded based on shrub vegetation in the polygons (e.g., "Western juniper/Wyoming big sagebrush" polygons were recoded "Wyoming big sagebrush"), or based on the composition of adjacent polygons. On-screen digitizing was sometimes required.
Forest boundaries were adjusted to match those of the Andrews map, with on-screen digitizing when necessary.
GLO surveys depict presettlement vegetation in Oregon as described by surveyors for the General Land Office between 1851 and 1909, when surveying township and section lines. Most low-elevation sites with arable land were surveyed between 1851 and 1865, while most foothill and mountainous areas were surveyed between 1865 and 1895. Coverages were created at 1:24,000 using databased transcriptions of survey notes for township and section lines, with standard USGS 7.5 topographic maps as a base. Soil Survey Geographic (SSURGO) digital data were used in the Willamette Valley to identify hydric soils and separate wet prairies from upland prairies. Because the survey presents vegetation patterns at a specific date, burned and storm-damaged forest patches were recoded to the corresponding forest type to make the coverage less time-specific. A map of current forest cover types for the Siskiyou National Forest was used to help delineate the extent of Douglas fir-tan oak forest east of the available GLO data in southwestern oregon.
A new Gap map was created by merging the first (1992) and second (1999) Gap vegetation maps, deleting slivers smaller than 40 ha, and examining each remaining polygon individually to label it. When labels from the two original Gap maps were not in agreement (e.g., 1992 Gap = Rigid sagebrush-Sandbergs bluegrass, 1999 Gap = Big sagebrush shrubland), J. Kagan was consulted to determine which label was most likely to be correct. In addition, an elevation cut-off of 1700m was selected, above which Wyoming big sagebrush was recoded as Mountain big sagebrush. The MRLC classified satellite image of Oregon was also used in the labeling process, principally to confirm the location of agricultural polygons.
After updating the H.J. Andrews coverage with other coverages, straight edges sometimes resulted from polygons abruptly ending at the end of a coverage and not continuing into the adjacent coverage. These were eliminated as best as possible through polygon recoding and on-screen digitizing. The most detailed coverage was given priority when vegetation types differed between two adjacent coverages: SSURGO dominant over Gap, GLO dominant over H.J. Andrews. Exceptions were made when the less detailed coverage was historically more accurate (e.g., H.J. Andrews vs. SSURGO).