Predominantly a sub-alpine species, the lodgepole pine’s new foliage can handle frost down to temperatures below freezing. It also easily sheds snow that would break the branches of other tree species and can survive in marginal soils. These characteristics allow it to outcompete other species and it dominates many high-elevation areas in Canada and the western USA. However, increasing temperatures and summer drought, decreasing winter precipitation, earlier loss of the snowpack and, particularly, increasing infestations of bark beetles appear to be affecting the tree’s range.

A team of North American researchers analysed 12,600 sites across a broad geographical range. They found evidence of declines going back to 1980, and estimate that by 2020, the pine’s range in the Pacific Northwest will have declined by eight per cent. Their projections also suggest that by 2080, the pine is likely to be absent from Oregon, Washington and Ohio, and be able to survive in only 17 per cent of its current range in western North America.

‘Less frost, combined with less snow, favours heavier levels of bark beetle infestation,’ said one of the study’s authors, Richard Waring of Oregon State University. We’re already seeing more insect attack, and we project that it will get worse.’

April 2011