2011-06-09

Mountain pine beetle activity may impact snow accumulation and melt, says CU-Boulder study

A new University of Colorado Boulder study indicates the infestation of trees by mountain pine beetles in the high country across the West could potentially trigger earlier snowmelt and increase water yields from snowpack that accumulates beneath affected trees.

Led by CU-Boulder geological sciences department doctoral student Evan Pugh, the study was undertaken near Grand Lake, Colo., adjacent to Rocky Mountain National Park, an area that has been devastated by mountain pine beetle attacks in recent years. Mountain pine beetles have killed more than 4 million acres of lodgepole pine trees in Colorado and southern Wyoming since 1996, the most severe outbreak on record.

Pugh and his team monitored eight pairs of tree stands, each pair consisting of one live stand and one dead stand roughly an acre each in size and located adjacent to each other, sharing the same topography, elevation and slope. The team monitored the two distinct phases of pine beetle tree death during the three-year study -- the "red phase" in which dead trees still retained red needles, and the "gray phase" in which all of the tree needles and some small branches had been shed, said Pugh.