Lumber recovery and deterioration of beetle-killed Douglas-fir and grand fir in the Blue Mountains of eastern Oregon.

Abstract

The purpose of this study was to determine the effect of time since death over a 4-year period on the amount of usable product volume and value, and to determine the species of fungi associated with wood deterioration in the stems of Douglas-fir and grand fir trees killed by bark beetles in northeastern Oregon. Sap rot, caused principally by Cryptoporus volvatus, increased significantly with years dead for both Douglas-fir and grand fir, but there were no significant differences in sap rot among d.b.h. (diameter at breast height) classes. Few insects were associated with defective wood, probably because of the relatively dry condition of the wood. Log breakage during logging in the live samples was less than 0.5 percent of the gross volume, and the amount of wood too defective to remove from the woods was about 2.5 percent in the dead Douglas-fir and 3.8 percent in the dead grand fir. Two-year-dead Douglas-fir recovered about 8 percent less lumber volume than live and 1-year dead Douglas-fir and all classes of dead grand fir. Three- and four-year dead Douglas-fir combined lost another 7 percent in lumber volume. Average lumber value (dollars per thousand lumber tally) and average log value (dollars per hundred cubic feet) analysis showed no difference among the live and 1-year-dead Douglas-fir samples. Average log value decreased about $60 from the live class to the grand fir dead class and another $60 for the Douglas-fir dead. Contrary to popular belief, the grand fir did not deteriorate as fast as the Douglas-fir or lose as much value as expected.

Citation

Parry, Dean L.; Filip, Gregory M.; Willits, Susan A.; Parks, Catherine G. 1996. Lumber recovery and deterioration of beetle-killed Douglas-fir and grand fir in the Blue Mountains of eastern Oregon. Gen. Tech. Rep. PNW-GTR-376. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 24 p