Forestlands pressured by residential development; Housing density near Washington State forests grew faster than in Oregon

The number of structures on private lands bordering public forests in Washington and Oregon has more than doubled since the 1970s. The greatest increases in density were on the fringes of public forests in Pierce, King, Snohomish, and Clark counties in Washington, and Deschutes County in Oregon. That growth brings higher risks of wildfire and more negative impacts on native fish and wildlife habitat.

Aerial photographs from 1995 (upper photo) and 2006 document the increased number of private structures -- most residential--on private lands near this unidentified section of National Forest
Aerial photographs from 1995 (upper photo) and 2006 document the increased number of private structures — most residential–on private lands near this unidentified section of National Forest. Photo: National Agriculture Imagery Program.

Using aerial photography to inventory structures and compare the pace of development next to public forests, the U.S. Forest Service’s Pacific Northwest Research Station found that the development growth rate on private lands bordering Washington DNR-managed state trust lands was twice that seen on private lands next to state forests in Oregon. The study’s authors speculate that some of the disparity is because Oregon enacted its Land Conservation Act in 1973 while the Washington State Growth Management Act did not become law until 1990 — the study covered 1974 to 2005. All the same, more and more private structures are being built on private lands bordering public forests in both states.

The expansion of development at the edges of public lands raises numerous management issues for forest managers, including:

  • Introduction of invasive plants;
  • Increases in unmanaged recreation;
  • Negative impacts on native fish and wildlife; and
  • More use of roads, which can lead to a rise in human-caused wildfire starts.

While fewer new structures were built next to U.S. Forest Service lands in Washington during the 30-year period studied, it was because DNR-managed lands and commercial forestlands tended to buffer federal lands from activities on private lands. Read the study.

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