Forest disturbance effects on snow and water yield in interior British Columbia

Abstract

Long-term studies at Mayson Lake (ML) and Upper Penticton Creek (UPC) in British Columbia's southern interior quantify snow-dominated hydrologic response to natural disturbances and logging. Following natural disturbance at ML, changes in snow accumulation related directly to mountain pine beetle attack were measurable by the fifth year following attack, when canopy transmittance had increased 24% due to needlefall. In year 1, April 1 snow water equivalent (SWE) was 48% higher in the clearcut than in the pine forest. This difference was reduced to 23% by year 8. A 3-year lag in snow response was also observed in a nearby burned stand where SWE was on average 27 and 59% higher in the clearcut than in the burn and forest, respectively. At UPC, April 1 SWE averaged 12% more and 12% less in a low and high elevation clearcut than forest, respectively, and snow disappeared ∼10 days earlier in both clearcuts. Partially as a result of snowmelt synchronization from higher with lower elevations after 50% of the treatment watersheds had been clearcut, April water yield increased and June to July yield decreased. Research results improve evaluation of hydrologic response to forest disturbance, including retention of beetle-killed stands versus salvage logging.

Canopy structure and topography effects on snow distribution at a catchment scale: Application of multivariate approaches

“…The decreasing importance of snow interception after spruce forest defoliation was proven in our study, which corresponds to results reported by Pugh and Small (2013) from the western United States. Our results also correspond to conclusions presented by Winkler et al (2015) who used both measured shortwave radiation and hemispherical photographs to derive the canopy transmittance. However, the reliability of results from the Ptaci Brook catchment could be influenced by the fact that our sampling sites are mostly in disturbed forests with dense treetops, and thus there is still a relatively big amount of snow intercept by the canopy formed by small branches.…”

“…However, field data bridge the gap between the real physical process and its conceptualization using suitable equation and parameters. Based on measured or simulated data, it is possible to estimate the effect of forest disturbances on snowmelt dynamics, such as windstorms, fires and insect attacks (Burles and Boon, 2011;Pomeroy et al, 2012;Pugh and Small, 2013;Winkler et al, 2015).…”

Streamflow response to clear‐cut logging on British Columbia's Okanagan Plateau

“…Following the extensive logging over half of the upper elevations of the watershed, melt in south-facing upper clear-cuts became synchronized with melt from the lower elevation forest, as described in Winkler, Spittlehouse, Boon, and Zimonick (2015), further advancing the timing, and increasing the magnitude, of high spring flows. This effect is corroborated by modelling work by Schnorbus and Alila (2013), who also showed earlier melt and increased runoff from highelevation clear-cuts augmenting that from lower elevations to produce higher peak flows.…”

Effects of forestry on summertime low flows and physical fish habitat in snowmelt‐dominant headwater catchments of the Pacific Northwest

“…As is typical of snowmelt‐dominant regions of the Pacific Northwest, the highest flows occur during the snowmelt freshet between April and June, followed by a general recession through summer and the following winter, with occasional increases in streamflow associated with autumn rainstorms. The soils in the Upper Penticton Creek catchments are generally less than 2‐m thick and consist of sandy loam and loamy sand that overlie glacial till and granitic rocks (Winkler, Spittlehouse, Boon, & Zimonick, ). Rainbow trout ( Oncorhynchus mykiss ) has been observed throughout the Upper Penticton Creek watershed.…”