Bugs Good For Sick Forest Report Claims

The beetle outbreak in B.C.’s interior is a sign of an overcrowded unhealthy forest says report. Bugs are actually part of the remedy.

Destructive bugs good for forest health:

by CBC News Online Last Updated: Tue Oct 30 21:13:27 2001

CORVALLIS, OREGON – Like forest fires, insect infestations may actually be healthy for forests in the long run, according to a new report.

Epidemics of insects such as the mountain pine beetle are actually a symptom of poor forest health, say the Oregon State University scientists who prepared the report, led by entomologist Tim Schowalter. ”There is now evidence that in many cases forests are more healthy after an insect outbreak,” said Schowalter in a statement.

Schowalter says insects that feed on plants can thin out forests that have become overcrowded because forest fire haven’t been allowed to burn. This reduces competition for water and nutrients and leads to a healthier forest. The overcrowding may be what is causing massive insect epidemics, he says.

Natural forests are protected against large outbreaks because the beetles’ pheromones can only be carried about three metres. In a healthy, open forest, that’s too far for the beetles to spread very far.

In an overcrowded forest, however, small, weak trees can allow the beetles to spread across the whole forest.

”When you have a highly destructive insect epidemic, what that really should be telling us is not that we have an insect problem, but that we have a forest health problem,” said Schowalter in a statement. Schowalter says the solution in these cases is not to eliminate the insects, but to address the original overcrowding problem, through controlled fires and other methods.

The report appears in this week’s issue of the journal Conservation Biology In Practice.