Lucie Royer
Natural Resources Canada, Canadian Forest Service

SERG Project #2004/07
Year of Project: 2004
Report Received: 2005


Technical Note


The hemlock looper (HL), Lambdina fiscellaria (Guen.), is a native insect that periodically defoliates coniferous forests of eastern Canada. Extensive tree mortality may occur after only one or two years of severe defoliation by this insect. This pest may impact on the timber resource and its management in two ways: by reducing tree growth causing a delay in the harvesting schedule; and by killing trees before the optimal time of harvesting. Outbreaks of this pest generally begin as small, scattered infestations, which explosively increase in size and distribution. Therefore, major issues for improving HL management are early outbreak detection and early intervention where it is required. Our current inability to accurately forecast insect densities and the damage that they cause, in terms of reduced wood supply, greatly hinders forest management, and requires accurate long-term predictions of future timber supply.

This project proposes to address these issues by developing predictive models to map initial defoliation risk, resulting growth loss and tree mortality, in relation to HL density.

The deliverable for 2004-2005 was to produce maps of susceptibility to HL (risk of defoliation) with NL government contribution. In addition, we sampled HL population in 15 sites (5 of each: low, moderate and high initial HL density based on mean number of eggs during the spring) at the egg, larval and pupal stages.