A Conceptual Model Of Water Quantity Impacts From Insect-Induced Tree Death In Coniferous Forests
Gordon, Eric 1 ; Pugh, Evan 2
1 Western Water Assessment
2 University of Colorado Boulder
In snow-dominated regions, forested watersheds often provide a considerable portion of the downstream water resources, and tree death can significantly alter many ecohydrologic processes including transpiration, canopy transmission and interception, subcanopy wind regimes, soil infiltration, and snow surface albedo. Bark beetles can change the hydrologic characteristics of landscapes in these regions by destroying forest canopies, often killing all of the overhead trees within lodgepole pine stands. Since 1996, an outbreak of the mountain pine beetle has killed more than 14,600 km2 of lodgepole pine and other tree species across Colorado, causing significant devastation near the headwaters of the Colorado River. Unfortunately, few empirical studies have documented the impacts of MPB infestations on hydrologic processes and little is known about the direction and magnitude of changes in water yield and timing of runoff due to insect-induced tree death. We are working to combine existing research on forest ecology, hydrology, and clear-cutting studies to create a conceptual model of the hydrologic effects of MPB-induced tree death during different stages of mortality. We separate out the primary hydrologic processes for living forest stands, stands in multiple stages of death, and long-dead stands undergoing regeneration. This conceptual model is intended to identify avenues for future research efforts