Measurement of snow interception and canopy effects on snow accumulation and melt in a mountainous maritime climate, Oregon, United States

Abstract

[1] The results of a 3 year field study to observe the processes controlling snow interception by forest canopies and under canopy snow accumulation and ablation in mountain maritime climates are reported. The field study was further intended to provide data to develop and test models of forest canopy effects on beneath-canopy snowpack accumulation and melt and the plot and stand scales. Weighing lysimeters, cut-tree experiments, and manual snow surveys were deployed at a site in the Umpqua National Forest, Oregon (elevation 1200 m). A unique design for a weighing lysimeter was employed that allowed continuous measurements of snowpack evolution beneath a forest canopy to be taken at a scale unaffected by variability in canopy throughfall. Continuous observations of snowpack evolution in large clearings were made coincidentally with the canopy measurements. Large differences in snow accumulation and ablation were observed at sites beneath the forest canopy and in large clearings. These differences were not well described by simple relationships between the sites. Over the study period, approximately 60% of snowfall was intercepted by the canopy (up to a maximum of about 40 mm water equivalent). Instantaneous sublimation rates exceeded 0.5 mm per hour for short periods. However, apparent average sublimation from the intercepted snow was less than 1 mm per day and totaled approximately 100 mm per winter season. Approximately 72 and 28% of the remaining intercepted snow was removed as meltwater drip and large snow masses, respectively. Observed differences in snow interception rate and maximum snow interception capacity between Douglas fir (Pseudotsuga menziesii), white fir (Abies concolor), ponderosa pine (Pinus ponderosa), and lodgepole pine (Pinus contorta) were minimal.

A Process-Based Application of State-and-Transition Models: A Case Study of Western Juniper (Juniperus occidentalis) Encroachment

“…2) subsequent sublimation losses were generally close to zero, and 3) sublimation was approximately 5% of winter precipitation (Stork et al, 2002). That site was wetter (average winter precipitation of 2000 mm), lower (1200 m), and more densely forested (30-to 50-m canopy heights, 65%−80% canopy closure).…”

“…The South Mountain Experimental Catchments are located in the interior Western United States, which is generally cooler, drier, and more open in terms of canopy compared with the Oregon study site (Stork et al, 2002). Lower vegetation generally becomes covered with snow early in the winter.…”

Instrumental method for reducing error in compression-derived measurements of rainfall interception for individual trees

“…Historically, direct measurements of water fluxes at varying temporal resolutions have been performed using weighing lysimeters (e.g. Fritschen et al 1973, Edwards 1986, Storck et al 2002. Although weighing lysimeters have provided valuable insights into the roles of vegetation in hydrological processes (e.g.…”

Impact of land-use changes on snow in a forested region with heavy snowfall in Hokkaido, Japan

“…The lysimeters (each with a 16-m 2 surface area) were placed beneath a mixed forest canopy and were designed to measure the snowpack water equivalent on the ground and outflow. The full details of the design and construction of the lysimeters are provided by Storck et al (2002). Each lysimeter had a maximum design load of 1500 mm of SWE and was weighed by four load cells positioned under the centre of each quadrant of the lysimeter.…”

“…Hardy et al, 1997;Link & Marks, 1997;Pomeroy & Granger, 1997;Suzuki et al, 1999aSuzuki et al, , 2006Koivusalo & Kokkonen, 2002; 444 Kazuyoshi Suzuki et al Storck et al, 2002;Suzuki & Ohta, 2003;Zhang et al, 2004). Pyke & Andelman (2007) noted that it is important to consider land use when estimating snow cover.…”