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Dr. Christopher A. Hiemstra Cold Regions Res. and Engr. Lab. (CRREL) U.S. Army Corps of Engineers Fort Wainwright, AK Christopher.A.Hiemstra@usace.army.mil office: (907) 361-5488 mobile: (907) 347-1028 November 2010. Impact of Beetle Infestation on Hydrology. Favorable Conditions for Beetles.
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Dr. Christopher A. Hiemstra Cold Regions Res. and Engr. Lab. (CRREL)U.S. Army Corps of EngineersFort Wainwright, AK Christopher.A.Hiemstra@usace.army.miloffice: (907) 361-5488 mobile: (907) 347-1028 November 2010 Impact of Beetle Infestation on Hydrology
Favorable Conditions for Beetles • Even-aged forests • Drought-stressed trees • Warmer winters (higher beetle survival) • Lodgepole pine trees are experiencing high mortality, as seen by their red coloration. In this August 2007 aerial image of the Fraser Experimental Forest, Colorado, dead reddened trees cover vast areas.
Widespread Impact Raffa et al. 2008
Precipitation Throughfall Wind Speed Sublimation Transpiration Snow Melt Infiltration Runoff Interception Interception Interception Litter Snow Soil
Potential Impacts • Pre-disturbance • Canopy intercepts ~20-36% of snow • transpiration is ~38% of precipitation • higher shading, slower spring melt • Post-disturbance • lower interception • higher sublimation, evaporation, and radiation • faster runoff, earlier hydrograph peak • Unknowns • Transpiration (forest floor compensation?) • Runoff (greater or lower; spatially variable?)
Snow Modeling (Bewley et al. 2010) • Baker Creek, BC, Canada (1570 km2) • Lodgepole pine with 50-80% mortality • 10-20% increase in peak SWE • 10-15% faster melt rate