The pine forests of British Columbia which covered a significant portion of land in the past, have been reduced to negligible. The woods have been eaten up by the mountain bark beetles, which have long sustained in these woods and have always been destroying the clumps of pinewood. The number of mountain bark beetles in the pine forests of British Columbia has abruptly increased to dangerous levels in the last 20 years or more. A significant reduction in the density of forests was first noticed in century. This reduction was first attributed to the growing number of mountain bark beetles by a forest ecologist, Scott Green from the University of Northern British Columbia. In the past, the pine forest used to recede in summer but would regain its density in the winter. But over the past 20