Pine beetles waning in northern Alta., booming in south

There is reason for both celebration and despair among those fighting to prevent the dreaded mountain pine beetle from spreading east and destroying billions more trees.

According to the Alberta government's aerial surveys conducted in August and September, the number of infected trees has dropped significantly - by 35 per cent - in the northwestern part of the province thanks to on-the-ground work and some particularly cold days last winter.

But for 752,200 hectares of monitored provincial lands in the south, the momentum is going the other way.