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Abstract
We compared 45 photographs taken before 1925 to photographs taken as late as 1999 and documented landscape changes above 5,000 feet elevation in the Wallowa, Elkhorn, and Greenhorn Mountains of northeastern Oregon. We noted the following major changes from these comparisons: (1) the expansion of subalpine fir into mountain grasslands, (2) the invasion of moist and wet meadows by several tree species, (3) a loss of whitebark pine from subalpine habitats, (4) continued soil erosion stemming from livestock grazing long since discontinued, and (5) a high rate of natural gravitational mass wasting. The most important factor contributing to changes in woody vegetation has been a reduction in fire frequency. Fires that occurred before 1925 were nine times more frequent than those that occurred at the end of the 20th century. Historical land uses and origins of place names are described.
Keywords
Wallowas,
Elkhorns,
Greenhorns,
Oregon,
photography (repeat),
photo history,
land use,
long-term change,
landscape ecology,
tree encroachment,
whitebark pine,
recreation,
Eagle Cap Wilderness Area,
erosion,
fire frequency,
climate,
subalpine ecosystem
Citation
Skovlin, Jon M.; Strickler, Gerald S.; Peterson, Jesse L.; Sampson, Arthur W. 2001. Interpreting landscape change in high mountains of northeastern Oregon from long-term repeat photography. Gen. Tech. Rep. PNW-GTR-505. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 78 p
