Beetle infestations can turn forests from CO2 absorbers to releasers

Infestations of bark beetles, which kill trees in large numbers, have increased dramatically in recent years in the Western US and Canada — an increase that has been linked to warming temperatures, which have in turn been linked to human-induced climate change.

A 2008 study by W. A. Kurz of Natural Resources Canada and colleagues in the journal Nature has also shown that large pine beetle outbreaks — like the current one in British Columbia—can turn an area from a carbon sponge into a carbon spigot. Healthy forests capture and accumulate carbon from the atmosphere as they grow; but beetle-kill trees decay and release back into the air the carbon they had built up over decades.[[Kurz, W. A., C. C. Dymond, G. Stinson, G. J. Rampley, E. T. Neilson, A. L. Carroll, T. Ebata, and L. Safranyik. “Mountain pine beetle and forest carbon feedback to climate change.” (Abstract) Nature Vol 452. April 24, 2008. pp. 987-990.]]

Forests, when not dramatically disturbed by agents like insects and fire, accumulate carbon and can help offset the increase in atmospheric CO2 due to human activity.