Salvage harvest effects on advance tree regeneration, soil nitrogen, and fuels following mountain pine beetle outbreak in lodgepole pine

Griffin, Jacob; Simard, Martin; Turner, Monica

tvestlopment, pr s the potentialred first-year effects osapling density with tall (30–140 cm) sall exceeded 1600 stems ha1. Relative sp pine. Soil temperature at the litter–soil interts. Soil NH4+ concentration and resin bag N accumulation increased through time in all beetle-kiopy fuel load and canopy bulk density both were reduced; dead fuel depth, duff depth, and canopyof needle shedding after beetle-kill accounted for 25–40% of this total canopy fuel reduction. Sered fuel complex (immediate increase in dead woody surface fuels and expected long-term reductiuntreated stands.The extent and severity of recent native bark beetle (Dendroctonae) outbreaks in western North America have created a pressing need for forest managers to understand potential consequences of post-disturbance management. For example, post-outbreak imber harvest (i.e., salvage har) could alter future forest deveoductivity and susceptibility toubsequent disturbance. To assess for such consequences, we measuf post-outbreak timber harvest on tree regeneration, soil nitrogen (N) availability and fuels by using a paired and replicated before–after-control-impact (BACI) experimental design with eight pairs of 0.25-ha plots in beetle-killed lodgepole pine (Pinus contorta var. latifolia) in Greater Yellowstone (Wyoming, USA). Post-outbreak timber harvest reduced total (live + dead) lodgepole pine basal area by 90%. Total (advance regeneration) declined by about 50% following harvest, plings declining most, but mean post-harvest sapling density stiecies density was unaffected and remained dominated by lodgepoleface was warmer during summer in harvested stands, and soil NO3- concentration increased with harvest relative to untreated plolled plots and were not affected by harvest. Following harvest, dead woody surface fuels in all size categories doubled, and can base height did not differ between untreated and harvested plots. Harvest did reduce canopy fuels, but the natural progression alvage harvest seems unlikely to alter post-outbreak successional trajectories in these lodgepole pine forests. However, the alton in large-diameter fuels) in harvested plots could cause subsequent fire behavior and effects to differ between harvested and