The Mountain Pine Beetle — 25 Years After

It was about 25 years ago that managers in Tweedsmuir Provincial Park noticed a patch of beetle killed pine trees. It is popularly believed that this was the starting point for the infestation that ravaged much of the BC interior Lodgepole pine stands and, had aggressive measures been taken, the extent of the damage might have been reduced.

When faced with an outbreak of this type, a usual prophylactic measure is to deploy pheromone traps to attract beetles and then burn the concentrated area of infected trees to kill the larvae. In bigger infestations, large scale burns are prescribed over hundreds or thousands of hectares to fence in the outbreak.

Managers did conduct prescribed burning on over 600 ha in 1995 and again on 250 ha in 1997, according to records, but these proved insufficient to arrest the spread beyond the Park’s boundaries. Conditions for a beetle outbreak were ripe. In terms of the environment, a series of milder than normal winters suppressed beetle mortality.

The measurable impacts on the BC forest economy twenty-five years on have been striking.

First, the volume of Lodgepole pine in the harvest has nosedived. Before the infestation, Lodgepole constituted 55% of the harvest. Peak mortality was attained in 2005 and then began to fade to near zero a decade later. As operations to salvage the timber ramped up, it began to account for up to two-thirds of the cut before beginning to trail off to just a quarter by 2020. Gains in other species offset some of the loss but nowhere near all, leaving the aggregate harvest at about two-thirds of its levels 20 years ago.

Looking back, one could ask if the long-term management decisions, made by foresters and companies favoring Lodgepole monocultures, were optimal given the outcomes?

Given the recurring large value destruction in both trees and capital, might not a more nuanced approach to forest management have been a benefit in past timberland planning?

The full version of this article, written by FEA Partner Henry Spelter, appears in the monthly edition of FEA’s Lumber Markets Status and Trends (LMST) newsletter. The LMST is published weekly. To subscribe, and access this article and associated graphs, please contact Dave Battaglia.