Toothpick method of counting Dendroctonus brevicomis (western pine beetle) emergence holes. Sisters, Oregon.

Photo by: Beal and Whiteside Date: June 1933

Credit: USDA Forest Service, Pacific Northwest Region, State and Private Forestry, Forest Health Protection. Collection: Portland Station Collection; La Grande, Oregon. Image: PS-83

Note: "The number of ventilating holes per attack and per square foot of bark has been given attention in bark counts largely for the purposes of separating them from the count of new adult exit holes. In the 'toothpick method' of making bark counts they have been separated from exit holes whenever a toothpick completely penetrates the bark from an egg gallery." From: Miller, J.M. and F.P. Keen. 1960. Biology and Control of the Western Pine Beetle. Misc. publication 800. USDA Forest Service, Pacific Southwest Forest and Range Experiment Station. p. 17.

To learn more about this photo collection see: Wickman, B.E., Torgersen, T.R. and Furniss, M.M. 2002. Photographic images and history of forest insect investigations on the Pacific Slope, 1903-1953. Part 2. Oregon and Washington. American Entomologist, 48(3), p. 178-185.

For additional historical forest entomology photos, stories, and resources see the Western Forest Insect Work Conference site: <a href="http://wfiwc.org/content/history-and-resources" rel="nofollow">wfiwc.org/content/history-and-resources</a>