The report estimated that at least 530 million cubic metres of wood has already been killed, which is about 12 percent of the western province's total supply of salable pine -- a key softwood construction lumber.

But the report by British Columbia's Ministry of Forests said the number of trees killed annually appears to be declining as susceptible trees die off, and the infestation rate may return to pre-outbreak levels by 2015.

The insects have lived on lodgepole and ponderosa pine in Western Canada for thousands of years, but nature has controlled major outbreaks by killing the beetles through extreme winter cold or with forest fires.

The area has not had the required cold snap in recent years, and efforts to fight fires to protect the timber supply and area communities have increased the number of older trees, which are more susceptible to an insect attack.

Trees killed by the beetles can be harvested for several years after they have died, but the provincial researchers said that more needs to be known about how long that wait can be.

The report said that, based on current assumptions on sawlog shelf-life, some areas of the province now hit by the infestation could see a decline in timber supply within four or five years.

The drier dead trees are subject to more cracking, which reduces the amount of timber and plywood that can be produced from each log.