SNOWPACK COMPARISONS BETWEEN AN OPENING AND A LODGEPOLE PINE STAND

In the fall of 1993, two snow pillows were installed at a permanent data site located at Onion Park Research Natural Area on the Tenderfoot Creek Experimental Forest in central Montana. One pillow is located in a small open meadow, and the second pillow is located 25 m away under a dense forest canopy of lodgepole pine. The two pillows were installed to standard specifications for a Natural Resources Conservation Service snow telemetry data site. Measurements of snow water equivalent (SWE) were monitored on both pillows with a continuous water level recorder from 1993 through 1995 and electronic data recorder from 1995 to present. Manual manometer levels were read during each site visit to verify data recorder values. The annual maximum SWE on the canopy pillow has averaged 77 percent of the open pillow over the winters from 1993 to 2000. Melt rates under the canopy have averaged 46 percent of that in the open. On average, final melt-out of the canopy pillow is 9 days after the open pillow. Results from this research will be used to model changes in streamfiow volume and timing of peak streamflow after forest modifications in 2001. This information should also be usefUl for hydrologic modeling or for modeling hydrologic changes after a forest has been harvested, burned or changed in structure due to age, disease, insect infestations or blowdown.