The recent fire in Fort McMurray (Alberta, Canada) is a consequence of an intense drought that made forests susceptible to fires, home owners who build too close to these forested areas without heeding fire precautions and just the right wind conditions to send the fire into the town and residents scrambling to escape. The drought has also been accompanied by warmer winter temperatures, larger mountain pine beetle populations and many beetle killed trees.
Some believe that the mountain pine beetle tree kills have contributed to the fire season, but the conclusions lacks evidence. The experience in Northwest Canada has been a reduction in forest fires after mountain pine beetle infestations. Timing of drought and tree death may be important. Shortly after their death, pine trees have limbs full of combustable dead needles that could fuel a crown fire. However, one year later, all the needles are shed leaving needles on the ground and standing deadwood “Ghost Trees”. The Ghost Trees are less susceptible to fire than trees full of dead needles. If the dead needle stage coincides with wet weather, fire is not promoted. However, drought in combination with dead needles are limbs can create conditions for large forest fires.
Regardless, the mountain pine beetle would not be an issue without the warmer winter temperatures that accompany climate change. Climate change has opened the gates to mountain pine beetle’s northward invasion. During the transition from MPB susceptible trees to those more resistant to MPB, expect these ecosystems to be disrupted and more “ecotastrophes” such as the Fort McMurray Fire to become more common.