ECONOMIC-LOSSES RESULTING FROM AMBROSIA BEETLE INFESTATION OF SAWLOGSIN COASTAL BRITISH-COLUMBIA, CANADA

Estimates of ambrosia beetle damage on 10 log grades, commonly used in sawmills of coastal British Columbia, were determined by the sawmill team of an Ambrosia Beetle Task Force during 1990-1992. A total of 417 ambrosia beetle attacked logs were evaluated in eight cooperating saw mills. Test logs were processed into lumber products, graded, and valu ed. Estimates of dollar loss per cubic metre for various log diameter classes were made. The average losses for the 10 log grades with respe ct to grade of lumber, with and without pinholes, ranged from $3.27 to $77.40/m3 of log. Changes in sawing patterns as a result of ambrosia beetle infestation were also assessed. The loss of deep clear potentia l on high-grade logs increased value losses by 57%. One third of large pulp logs were sawn for lumber. Ambrosia beetle infestation of sawn l arge pulp logs resulted in-$19.20/m3 degrade loss.