Canada — It may only be the size of a grain of rice, but one species of beetle has managed to alter Canadas climate. The mountain pine beetle has increased summer temperatures in British Columbia by around 1C by destroying huge areas of forest, according to research. By reducing the amount of water pumped into the air by vegetation, the beetle has had as big an impact on local climate as forest fires, say scientists. The increase in temperature has resulted from the sun’s energy heating up the ground surface instead of being used up evaporating water. The change in surface energy balance could alter cloud formation and rainfall, said the researchers writing in the journal Nature Geoscience. Over the past decade, infestation by the beetle has affected almost 20 per cent of the whole of provincial British Columbia, a region of some 105,000 square miles of pine forest.
Scientists made the link between the beetle attacks and climate after studying satellite data. They found that throughout the affected forest, the beetle had reduced summer evapotranspiration – the movement of water from the ground to the atmosphere by plants – by 19 per cent. Author Dr Holly Maness, from the University of California at Berkeley, US, and colleagues wrote: Land cover change in the case of insect infestation is less well ordered than in other types of disturbance, because both the scale of the impacted areas and the level of mortality within affected areas are variable. Future work is needed to understand the circumstances under which patchy and variable forest mortality drive significant secondary changes in regional climate.
The beetle has had as big an impact on local climate as forest fires It has affected 20% of British Columbia’s 105,000 square miles of pine forest
The failure was in the forest areas.Advertisement
Following a 10-year strategy, ACT fire managers have created a mosaic across the landscape of different fuel levels, burning at every opportunity.
But forests have been too wet to burn this spring and the past two summers.
A network of 500 fire trails and strategic burns along the north-west urban edge, heavy grazing and extra grass slashing will create a fortress for the territory which forecasters say faces a higher than average risk this summer.
After a fire-fuelled tornado in January 2003 killed four Canberrans and frightened thousands more, CSIRO fire expert Phil Cheney told the subsequent inquiry the fire’s penetration into urban areas under extreme conditions did not reflect a failure of fuel management on the urban interface.