Washington Department of Natural Resources posted by:
USDA Forest Service
Pacific Northwest Region
Forest Health Protection



Washington Forest Health Issues in 2003

Washington Forests
General Forest Conditions
Aerial Survey
Overview
Survey Results

Animal and Abiotic
Drought
Fire
Bear Damage

Western Spruce Budworm (WSBW)

A new defoliation event occurred this year on the east slopes of the North Cascades with almost 2,300 acres of defoliation recorded. In addition, the budworm outbreak in southwest Washington made a pronounced resurgence this year with 136,500 acres of defoliation recorded in southeast Washington in 2003. The Yakima area was again active, and the areas around Bumping Lake and Rimrock Lake showed continued activity with yet another impressive spread to the west and north from previous years.

The total number of affected acres mapped in Washington over the last several years are as follows:

  • 1999:189,700
  • 2000:383,000
  • 2001:236,000
  • 2002:56,567
  • 2003:138,797

Multiple landowners monitor pheromone traps as an early warning of rising populations. The map on the right shows the trapping results for 2003.
Part of the Goat Peaks Wilderness Area defoliated by western spruce budworm; photo by WA Dept. of Natural Resources
This photo taken during the 2003 aerial survey shows WSBW defoliation near the goat peaks wilderness area as seen from the air.

Additional areas of light defoliation were likely not mapped because it is very difficult to detect lightly defoliated trees from the air in smoky conditions. Moreover, Douglas-fir beetle is active in many areas where repeated defoliation has weakened trees, but often goes undetected since these trees are denuded of foliage.

Additional Information

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