Forest Investment Account

Abstract of FII Project R04-016

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Attack dynamics and management implications of western balsam bark beetle in manipulated and natural subalpine fir ecosystems.

Author(s): MacLauchlan, Lorraine (BC Ministry of Forests)
Subject: Biology, Entomology, Forestry, Pathology, Silviculture/Forest Management Systems
Series: Forest Investment Account (FIA) - Forest Science Program


Dryocoetes confusus is the most destructive insect pest of subalpine fir. D. confusus prefers downed subalpine fir and susceptible standing trees that are the largest and oldest in a stand. Outbreak dynamics seem closely linked with host susceptibility, which can be mimicked by various management practices such as falling trap trees and baiting. However, relative brood success within these two host conditions is not known, nor is it known if an abundance of downed host material will trigger an outbreak, similar to that observed with spruce beetles. Two field trials were established in 2000-2001 to study the progress of Dryocoetes population dynamics in treatments with felled trees, baited trees and a natural scenario. The progression of attack in the stand, density of attack on standing and felled trees, and insect fecundity and development within hosts has been monitored since the trials were established. As well, ten permanent sample plots are assessed annually for Dryocoetes attack and blowdown.

For further information, please contact Lorraine Maclauchlan, BC Ministry of Forests (

Updated September 08, 2005 

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