Evan Pugh

University of Colorado Boulder | CUB · Department of Aerospace Engineering

The mountain pine beetle is killing many trees in Colorado's high-elevation forests. The thinned canopies found in dead tree stands should intercept less snow and transmit more radiation than canopies in living forests, altering snow accumulation and melt processes. We compare snow, forest, and meteorological properties beneath living and pine beet...

In regions of western North America with snow-dominated hydrology, the presence of forested watersheds can significantly influence streamflow compared to areas with other vegetation cover types. Widespread tree death in these watersheds can thus dramatically alter many ecohydrologic processes including transpiration, canopy solar transmission and s...

Bark beetles have killed more than 100,000-km2 of pine forest in western North America, causing trees to lose the majority of their canopy material and potentially leading to enhanced subcanopy snow accumulation. Over a 45-day period, we tested this hypothesis by measuring daily snow accumulation in three living and two dead lodgepole pine stands a...

A recent unprecedented epidemic of beetle-induced tree mortality has occurred in the lodgepole pine forests of Western North America. Here, we present the results of studies in two subalpine forests in the Rocky Mountains, one that experienced natural pine beetle disturbance and one that experienced simulated disturbance imposed through bole girdli...

The recent mountain pine beetle epidemic in the Colorado River Basin has resulted in widespread tree mortality in pine stands across the Colorado Plateau. Because of complex micro-scale (i.e. tree well scale) interactions between vegetation and snow processes, one of the most significant issues resulting from this epidemic is the potential hydrologi...

http://utilityii.com/bark-beetles-cause-for-concern-in-snowy-western-watersheds/

Remote sensing is a valuable tool for monitoring the impact of landscape-scale disturbances on ecosystem structure and function. We explore the impact of the ongoing insect outbreaks Dendroctonus ponderosae , D. rufipennis , and Ips spp. on southern Rocky Mountain forests, with the goal of assessing the sensitivity of leaf area index LAI and phenol...

Litter from bark beetle-infested trees and aeolian dust deposition are current perturbations to the snowpack surface albedo in subalpine forested environments in the Colorado River Basin. We examine the combined effects of dust and litter on snow surface albedo through field and controlled laboratory modification of snow surface dust and litter con...

The high-elevation forests that are a primary source for Colorado's domestic and agricultural water needs are changing rapidly due to an infestation by the mountain pine beetle (MPB). MPB are native to Colorado's high elevation forests. However, the frequency of MPB infestation and resulting tree death has increased dramatically over the past 15 ye...

In regions with snowpack-dominated hydrology, such as the upper Colorado River Basin, forested watersheds are the source of most (>70%) of the annual runoff. Widespread tree mortality significantly alters many ecohydrologic processes including transpiration, canopy transmission and interception, subcanopy wind regimes, soil infiltration, and snow s...

The recent mountain pine beetle epidemic in the Colorado River Basin has resulted in widespread tree mortality in pine stands across the Colorado Plateau. The mountain pine beetle (MPB) infests trees over large areas at a fairly rapid rate, resulting in a loss of nearly all canopy biomass within three to four years. One of the most significant issu...

Nearly two million acres of lodgepole pine forest in Colorado have been infested by mountain pine beetles (MPB) since 1996. In this study we examine the impact of tree death on snowpack accumulation and ablation. Here, we show results after one year of beetle impact. Snowpack and meteorological properties were measured at eight pairs of dead and li...

Since 1996, roughly 1.5 million acres of lodgepole pine forest in Colorado have been infested by mountain pine beetles (Dendroctonus ponderosae). We measured physical snowpack properties (depth, density, and temperature) under stands of both living and dead lodgepole pines in the Colorado Rockies. This data allowed us to investigate the effect of i...