06/18/2014 06:29 EDT | Updated 08/18/2014 05:59 EDT

Winter cold killed some pine beetles in Alberta, but some survived icy grip

EDMONTON - A cold winter in Alberta helped killed mountain pine beetles in some parts of the province, but the destructive bugs survived in some forests.

A government survey says there wasn’t much change to a large area surrounding Lesser Slave Lake,.

But the pest's numbers were diminished in wooded areas south of Grande Prairie, northwest of Edson and west of Manning.

The survey was done by cutting core samples from trees and comparing the number of living and dead beetle larvae under the bark.

Environment Minister Robin Campbell says the province must continue to take aggressive action against the beetles.

He says the survey results indicate that pine beetle populations are unlikely to decline naturally in the near future.