Pine beetles eat Canada, boosting GHG emissions
Jeremy Hance, mongabay.com
July 10, 2008


Plague of beetles causes massive deforestation in Canada, contributes to climate change



The mountain pine beetle, a small tree-devouring insect, has deforested an area of British Columbia the size of Louisiana — over 130,000 square kilometers. The 5 millimeter insect is a perfect tree-destroying machine. The beetles bore through the tree's bark to reach the phloem of the tree, which contains the tree's organic nutrients. The beetles then feed on these nutrients and lay their eggs. The trees defend themselves by secreting extra resin, but the beetles are often able to combat this by releasing a blue fungi. In about two weeks time, the tree turns a tell-tale red and essentially starves to death. The mountain pine beetles move on.

The mountain pine beetle, like forest fires, is a part of the natural cycle of a forest. However, the current outbreak is abnormal in its scale. Usually fire and winter cold snaps keep the beetles under control. But intense forestry management has meant a dearth of forest fire. Combined with a long series of unseasonably warm winters, the beetles have been spreading further and further every year. Many blame the warm winters, and therefore the scale of the infestation, on climate change. There was hope that this winter — which was colder than many previous — might stop the beetles, but so far it doesn't seem to have been effective as scientists hoped.


Aerial view of extensive attack by mountain pine beetle. Photo by Lorraine Maclauchlan, Ministry of Forests, Southern Interior Forest Region
British Columbia is not the only victim — in 2002 the beetles reached Alberta. According to an article in The Economist, the beetles have now entered the parks of Banff, Jasper, Kananaskis, and have traveled as far as Slave Lake in the central-north of the province. The beetle has also made its way south into the American west, attacking Colorado forests vigorously, with 6,000 square kilometers falling victim so far.

One of the great concerns now is that the beetles will reach the boreal forest. The boreal is made up primarily of jack pines, which have no natural defenses against pine beetles.

"I don't want to be alarmist, but it is certainly feasible that a future outbreak later this century could go across the boreal," Werner Kurz, who studied the outbreak in regards to carbon emissions, told the Vancouver Sun. "Basically the warmer the climate gets, the greater the chances that this could occur."

Pine beetles as carbon emitters

In April it was announced that the massive infestation, which was been aided by a warming climate, has in turn become a net contributor to climate change. A study in Nature showed that the pine beetle plague had turned British Columbia's forest from a carbon sink into a massive carbon emitter. The scientists estimate that between 2000 and 2020, 990 megatons of carbon will be released into the atmosphere (five times more than Canada's annual emissions from transportation).

"When trees are killed, they no longer are able to take carbon from the atmosphere. Then when dead trees start to decompose, that releases carbon dioxide into the atmosphere," Kurz, who headed up the study, told National Geographic. The Senior Research Scientist with the Canadian Forest Service believes that the current outbreak and other insect infestations should be factored into the carbon cycle.

Solutions to the problem are increasingly difficult since the infestation has grown to such a scale. Kurz has suggested that many of the dead trees should be logged — leaving some to decompose and enrich the soil — while a massive replanting of new trees should be undertaken. Turning the dead trees into biofuels has also been mentioned. The idea is controversial, but Kurz told the Vancouver Sun that it should be seriously considered, "You are creating a biofuel that is not competing with the human food supply."

Whatever happens to the areas already devastated, many wait to see how long it will take before natural processes finally stop the mountain pine beetle. However, if the insects reach the boreal forests all bets may be off.








CITATION:
Jeremy Hance, mongabay.com (July 10, 2008).

Pine beetles attack Canada, boosting GHG emissions.

http://news.mongabay.com/2008/0710-hance_pine_beetles.html