British Columbia is currently experiencing a mountain pine beetle epidemic throughout the range of lodgepole pine forests in the province. This epidemic is the result of a number of factors including natural beetle population cycles, continuous mild winters, and an abundance of uniformly mature pine forest stands. The brown trees are all dead and can be seen for miles in some areas of central British Columbia.
Forestry experts and entomologists agree that you can't "stop" a beetle expansion such as we now see across British Columbia. Only nature can do this through two consecutive very cold winters. However, management activities are planned and implemented to try to slow the rate of expansion until cold winters can stem the rapid expansion of beetle populations.
Will the effects of the mountain pine beetle harm the animals living in the forests?
Mountain pine beetles kill trees, and the effect of this can impact wildlife in the forests as well. But these effects can be beneficial.
When natural processes that change forests are prevented (such as insects, disease and wildfire), the result can be a much more uniform and static ecosystem. If this occurs, the variety of habitats for wildlife are reduced from what may have been originally occurring and fewer species may result.
Natural processes such as wildfire, insects, disease and wind break up the forests and create areas with different habitats. These varied habitats can attract a wider variety of wildlife and benefit the overall diversity and health of the forest ecosystems. For example, the caribou of the Tweedsmuir and Entiako areas depend on lichens as a key food source. Beetle killed trees lose their foliage and more light can reach down through the forest. This results in increased lichen growth and a better chance of survival for the caribou.
Severe prolonged cold weather or a loss of host trees is the only way to stop the spread of mountain pine beetle. In the Cariboo-Chilcotin, the infestation in the early 1980s continued for ten years, before this weather pattern reduced the spread of mountain pine beetle.How cold does it have to get to kill off the beetle?
Temperatures must consistently be below -35C to -40C for several straight days to kill off large portions of mountain pine beetle populations. In the early fall or late spring, sustained temperatures of -25 Celsius can freeze mountain pine beetle populations to death or a sudden cold snap is more lethal in the fall, before the mountain pine beetles are able to build up their natural anti-freeze (glycerol) levels. Cold weather is also more effective before it snows. A deep layer of snow on the ground can help insulate mountain pine beetles in the lower part of the tree against outside temperatures. Wind chill affects mountain pine beetles, but is usually not sustained long enough to significantly increase winter mortality.
What are the predictions for winter this year?
Even though it's a weather phenomenon that forms at the equator, La Nina could have a major impact on Canada this winter. La Nina moves cooler air and water around the Pacific Ocean. It's been seven years since the last one. In the past, La Nina caused drought and floods around the world. It also whips up more hurricanes in the Atlantic. It generally means from B.C. to Thunder Bay, a colder and snowier winter
In the fall, La Nina tends to bring a longer, colder, and wetter-than-normal winter. While its impact is harder to predict for eastern Canada, westerners should prepare for a rough season. But what will happen is still up in the air. Since its last appearance in 2000, the planet's climate has changed quite a bit. Global warming has progressed and could alter its effects.
So we are all hoping for an extremely long cold winter this year to save our forests.