Presentation Type

Poster

Abstract

Forest litter within a snowpack changes the snow albedo, affecting springtime melt rates. Albedo, the percent of shortwave radiation a surface reflects, is high in snow and low in forest litter. Litter absorbs shortwave radiation and reemits longwave radiation, which should increase snowmelt rates. We are conducting a two-part study to (1) quantify winter litterfall rates in relation to canopy cover and local tree spacing, and (2) to determine the effects of litterfall density on melt rates. We predicted litterfall will be greatest in tree clumps, less near individual trees, and least in canopy openings; and that snow melt rates will increase with litter inputs, but potentially decrease at very high litterfall rates due to an insulation effect. The research takes place at Lubrecht Experimental Forest, at 1260 m of elevation. To quantify litterfall rates we deployed litter traps (1 m2) beneath six randomly selected tree clumps, individual trees, and canopy openings (n = 18 traps total). Traps will be collected after melting is complete and litter weighed. We are using a litter addition experiment (randomized block design) to investigate litterfall effects on snow attributes. Experimental blocks are placed in large canopy openings to limit natural litter inputs. Four litter addition amounts (0.1 kg/m2, 0.4 kg/m2, 1 kg/m2, and 4 kg/m2) or a control treatment are applied at random to 1 m2 plots, replicated in nine blocks. During melt season we will measure snow depth, snow water equivalent, albedo, percent snow coverage, and date of snow disappearance in each plot. The results of this research will give land managers more information on how changes to forest canopy cover, and the resulting change in litter fall, will affect snowmelt. This will allow land managers to design forest thinning and restoration prescriptions with a better understanding of the effects on water yield.

Category

Physical Sciences

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Apr 11th, 11:00 AM Apr 11th, 11:00 AM

The Effects of Forest Litterfall on Snow Melting Rates in Northern Rockies Mixed-Conifer Forests

Forest litter within a snowpack changes the snow albedo, affecting springtime melt rates. Albedo, the percent of shortwave radiation a surface reflects, is high in snow and low in forest litter. Litter absorbs shortwave radiation and reemits longwave radiation, which should increase snowmelt rates. We are conducting a two-part study to (1) quantify winter litterfall rates in relation to canopy cover and local tree spacing, and (2) to determine the effects of litterfall density on melt rates. We predicted litterfall will be greatest in tree clumps, less near individual trees, and least in canopy openings; and that snow melt rates will increase with litter inputs, but potentially decrease at very high litterfall rates due to an insulation effect. The research takes place at Lubrecht Experimental Forest, at 1260 m of elevation. To quantify litterfall rates we deployed litter traps (1 m2) beneath six randomly selected tree clumps, individual trees, and canopy openings (n = 18 traps total). Traps will be collected after melting is complete and litter weighed. We are using a litter addition experiment (randomized block design) to investigate litterfall effects on snow attributes. Experimental blocks are placed in large canopy openings to limit natural litter inputs. Four litter addition amounts (0.1 kg/m2, 0.4 kg/m2, 1 kg/m2, and 4 kg/m2) or a control treatment are applied at random to 1 m2 plots, replicated in nine blocks. During melt season we will measure snow depth, snow water equivalent, albedo, percent snow coverage, and date of snow disappearance in each plot. The results of this research will give land managers more information on how changes to forest canopy cover, and the resulting change in litter fall, will affect snowmelt. This will allow land managers to design forest thinning and restoration prescriptions with a better understanding of the effects on water yield.