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Broad Land Cover/Use Findings

State of Oregon
National Resources Inventory (NRI) Results
(Revised December 2000)
 

See Broad Land Cover/Use Topic List for detailed results.
 

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Definition and Categories

Land Cover/Use is a term that includes categories of land cover and categories of land use. Land cover is the vegetation or other kind of material that covers the land surface. Land use is the purpose of human activity on the land; it is usually, but not always, related to land cover. The NRI uses the term land cover/use to identify categories that account for all the surface areas of the United States.

The 12 NRI Broad Land Cover/Use categories are cultivated cropland, non-cultivated cropland, Conservation Reserve Program (CRP) land, pastureland, rangeland, forestland, other rural lands (minor lands), rural transportation, urban lands, small water, large water, and federal land.

 

Results for Land and Water in 1997

In 1997, total surface area of Oregon was estimated to be 62,161,000 acres. This consisted of 61,340,800 acres of land and 820,200 acres of permanent water. Pacific Ocean waters were not included.

1997 Estimates for Oregon
Category Acres Percent
Federal Land 31,260,400 50.3%
Forestland 12,642,800 20.3%
Rangeland 9,286,300 14.9%
Cultivated Cropland 2,676,800 4.3%
Pastureland 1,960,700 3.2%
Noncultivated Cropland 1,084,900 1.7%
Urban Lands 845,300 1.4%
*Other Rural Lands 724,000 1.2%
Large Water 657,900 1.1%
Conservation Reserve Program Land 482,600 0.8%
Rural Transportation 377,000 0.6%
Small Water 162,300 0.3%
Total Surface Area 62,161,000 100.00%
*Farmsteads, farm structures, field windbreaks, barren land, and marshland

 

Non-Federal Land and Water Results for 1997

In 1997, non-federal land and water in the state was estimated at 30,900,600 acres. The largest non-federal category in Oregon was 12,642,800 acres of forestland (40.9% of non-federal lands). This was followed by 9,286,300 acres of rangeland (30.1%), 4,244,300 acres of cropland and Conservation Reserve Program (CRP) lands (13.8%), 1,960,700 acres of pastureland (6.3%), 845,300 acres of urban land (2.7%), 724,000 acres of other rural lands (2.3%), 657,900 acres of large water (2.1%), 377,000 acres of rural transportation lands (1.2%), and 162,300 acres of small water (0.5%).

Land use is not static, it is surprisingly dynamic. There are annual shifts in and out of different uses. In agriculture, there are constant shifts in the use of land among cropland, pastureland, rangeland, and forestland to meet production needs, implement rotations of land in and out of cultivation, diversify income, and sustain soil resources.

 

Water and Rangeland Fluctuations

Natural processes also cause shifts in land classification. One unusual aspect of the Oregon results is a wide variation in the large water estimates for the state. Large water is defined as lakes at least 40 acres in size and streams at least 660 feet wide. Large water estimates range from a high of more than 761,000 acres in 1987 to a low of about 495,000 acres in 1992. These changes were due primarily to the expansion and contraction of large closed basin lakes in Harney, Lake, and Klamath counties in southeastern Oregon. Long term wet and dry cycles dramatically effect the size of these lakes. 

Adobe Acrobat DocumentChart for Water Areas (20 KB)
Adobe Acrobat DocumentTable for Water Areas (11 KB)

 

Much of the change in rangeland acreage during the NRI sampling years is due to these same long term wet and dry cycles. Areas exposed by long term drying of lakes are often classified as rangeland. 

Adobe Acrobat DocumentChart for Rangeland (22 KB)
Adobe Acrobat DocumentTable for Rangeland (13 KB)

 

The relative changes estimated in the NRI data correlate well with other available climate data. This data indicates that 1987 was a high lake water year and 1992 was a low lake water year for southeastern Oregon.

 

Cropland

From 1982 to 1997, cropland in Oregon declined an estimated 560,000 acres, from about 4.4 million acres to about 3.8 million acres. However, most of this was due to over 480,000 acres of highly erodible and environmentally sensitive cropland being enrolled in the voluntary Conservation Reserve Program by Oregon farmers. In addition, an estimated 63,000 acres of cropland was converted to urban lands from 1982 to 1997.  

Adobe Acrobat DocumentChart for Cropland and Conservation Reserve Program Land (22 KB)
Adobe Acrobat DocumentTable for Cropland and Conservation Reserve Program Land (13 KB)

 

Grazing Lands and Forestland

Non-federal pastureland, rangeland, and forestland also declined in acreage from 1982 to 1997. Conversion of these lands to urban uses was one factor in this decline. An estimated 58,600 acres of pastureland, 22,700 acres of rangeland, and 105,500 acres of forestland were converted between 1982 and 1997.

Adobe Acrobat DocumentChart for Pastureland (22 KB)
Adobe Acrobat DocumentTable for Pastureland (13 KB)

 

Adobe Acrobat DocumentChart for Rangeland and Forestland (22 KB)
Adobe Acrobat DocumentTable for Rangeland and Forestland (13 KB)

 

Urban Lands

The largest increase in acreage by land use on non-federal lands was for urban lands, which grew from an estimated 585,000 acres in 1982 to about 845,000 acres in 1997. This is an increase of 44%.  

Adobe Acrobat DocumentChart for Urban Lands (22 KB)
Adobe Acrobat DocumentTable for Urban Lands (13 KB)

 

For more detailed information on Conversion see Conversion to Urban Lands, Farmsteads, Rural Transportation.

To see all results, select Geographic Area.

Send comments and suggestions to the Oregon Resources Inventory Team
Last Modification: Monday, July 28, 2003

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