North Platte - Pine Beetle_Water Project - Overview - Section 4

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Water From Colorado's Bark Beetle Forests -Project Overview Elder, Rhoades & Hubbard; USFS Rocky Mountain Research Station; 5/15/08 EXECUTIVE SUMMARY Within the next few years, nearly all the mature lodgepole pine growing in the headwaters of the North Platte and Upper Colorado Basins and across much of Colorado will succumb to mountain pine beetle attack. Citizens of the Colorado high-country recognize that this large-scale beetle outbreak and associated forest management will influence the delivery of clean water from headwater basins for the coming decades. After decades of declining forest management activity, the public now supports and expects rapid management solutions to treat the current forest health situation. This study will compare how four management alternatives commonly used in beetle- killed pine forests influence snow accumulation, potential streamflow, water quality, soil productivity and forest recovery. The management alternatives result in distinct amounts of aboveground structure, surface roughness and soil disturbance. At one end of the spectrum, the No Action option retains standing snags, downed wood and maximum surface roughness. Logging conducted using Watershed Protection goals retains logging residue to maintain roughness and avoid soil disturbance. In contrast, the Fuel Reduction option removes slash, and the Forest Regeneration option combines slash reduction and mechanical scarification to enhance seedling establishment. Assessment of these management alternatives will improve decisions on how to sustain delivery of clean water and forest productivity from lands impacted by mountain pine beetle. PROJECT OVERVIEW Extensive mountain pine bark beetle (MPB) outbreaks are transforming forested watersheds of Colorado and western North America. Nearly half of Colorado's lodgepole pine-dominated forests had been attacked by bark beetles by 2006 (National Forest Health Monitoring, 2006), and by 2007 beetles had spread to 1.5 million acres statewide. It is currently projected that Colorado will lose all mature lodgepole pine within the next three to five years. Similar outbreaks plague lodgepole and other pine species throughout the Rockies; it is estimated, for example, that 80% of British Colombia's lodgepole pine ecosystem will succumb to beetles within a decade (Aukema et al. 2006). MPB is native to western forests, but prolonged drought and increased winter temperatures coupled with the expanse of aging forests have created a "perfect storm" of climatic and forest conditions (Logan et al. 2003). Current bark beetle outbreaks will likely have a prolonged influence on the delivery of clean water from infested watersheds of Colorado. Lodgepole stands lose 50 to 90% of the live forest overstory following MPB attack (Fraser Experimental Forest 2008 unpublished data), and pine mortality augments the amount of water and nutrients available for use by understory vegetation and runoff. Decreased snow interception by tree canopies is responsible for the increased snowpack accumulation following logging (Troendle and King 1985) and though the forest overstory will deteriorate more slowly following beetle attack, similar physical processes will regulate the magnitude and timing of post-beetle snowmelt. The net effect of the changes in snowpack accumulation and