Pugh's team also used devices known as pyranometers to measure the snow surface albedo and the transmission of sunlight through forest canopies. Fisheye camera images taken from the snow surface helped the researchers to calculate the size and structure of the various tree stand canopies, he said.
"The students really got something out of working on this project," said Small. "Not only did they get internship credit, they had a chance to conduct meaningful research."
A massive fire in the study area in the late 1800s resulted in most of the succeeding lodgepole pines to be about the same size and age, making them easier targets for pine beetles. While mountain pine beetle infestations are natural events, climate change probably has played a role in the most recent outbreak. Drought conditions in the West in recent years have caused living pines to absorb less water, decreasing their ability to produce enough sap to "pitch out" beetles that are attacking them, Pugh said.
Water managers in Salt Lake City have reported extra water in river basins that hydrologic models had not predicted, Pugh said, an indication beetle-killed trees are having an impact on meltwater.
With the exception of two studies in British Columbia looking at the effects of beetle- killed lodgepole pine trees on snow accumulation and melt on flat terrain at a single site, research regarding the hydrologic impacts of mountain pine beetles has largely been speculative, said Pugh.
"Our study is the first to analyze the multiple stages of tree death from mountain pine beetles and their different impacts on snow accumulation and snowmelt," said Pugh. "There is no on/off switch here -- only gradual changes.
"The effects of the beetle-killed tree stands in terms of snow accumulation are not going to affect ski resort seasons by any means," he said
|Contact: Evan Pugh|
University of Colorado at Boulder