TY - Generic T1 - Differential Snowpack Accumulation and Soil Water Dynamics in Aspen and Conifer Communities: Implications for Water Yield T2 - 75th Annual Western Snow Conference Y1 - 2007 A1 - LaMalfa, E.M. A1 - Leffler, A.J. A1 - Ryel, R.J. KW - SWE, conifer, aspen, snow interception, sublimation, soil saturation AB - Differences in snow water equivalent (SWE) in aspen and conifer stands in winters with low to high precipitation, sublimation rates of intercepted snow by conifer branches, and dynamics of soil moisture under aspen and conifer stands were in northern Utah. For low, average and high snowpack years, conifer stands averaged 33-44% lower SWE than paired aspen stands. Sublimation rates for sunlit simulated conifer branches were up to twice that of the ground snow surface; shaded branches had similar rates to the ground snow surface. When combined with the greater surface area of snow on conifer branches, sublimation could explain all or most of the differences in SWE between conifer and aspen stands. Soil column water content was generally higher in aspen throughout all periods of the year. For 2006, aspen stands were estimated to yield 400+ mm more water than the adjacent conifer stands and have saturated soil columns. In 2007, we predict that aspen soils will nearly reach saturation while conifer soils will be 100 mm below saturation. JF - 75th Annual Western Snow Conference T3 - Proceedings of the 75th Annual Western Snow Conference PB - Western Snow Conference CY - Kailua-Kona, HI UR - sites/westernsnowconference.org/PDFs/2007LaMalfa.pdf ER - TY - Generic T1 - Difference in Water Balance Between Aspen and Conifer Communities: The Fate of Spring Snow Melt in a Northern Rocky Mountain Watershed T2 - 74th Annual Western Snow Conference Y1 - 2006 A1 - LaMalfa, E.M. A1 - Ryel, R. KW - Water balance, spring snowmelt, Rocky Mountains, sap flux, water yield, runoff timing, peak SWE, aspen, conifer, type conversion AB - Differences in water balance between mature deciduous quaking aspen (Populus tremuloides) and evergreen conifer (e.g. Abies concolor, Abies lasiocarpa, Picea engelmannii and Pseudotsuga menziesii) forest communities occur as a result of complex physical and biological interactions. To better understand the potential effects of aspen conversion to evergreen conifer on watershed water yield in the northern Intermountain West, USA, we assessed several water balance transfer mechanisms, including snow accumulation, ablation, evaporation/ sublimation, soil moisture recharge, and transpiration, to determine how major differences in water balance occur in adjacent mature aspen and conifer forests during spring snowmelt. Measurements of fall sap flux were indexed to determine the annual transpiration activity period for aspen and conifer communities. Soil moisture was monitored to determine the timing of soil moisture recharge during winter snow accumulation, and field observations of snow water equivalent (SWE) and snowpack sublimation were obtained. We found SWE was the factor most different between aspen and conifer stands, with conifer stands averaging 34% less SWE at peak snowpack than adjacent aspen stands. We conclude peak SWE is likely the most important factor affecting watershed water yield between aspen and conifer stands, but that differences in soil moisture accumulation could further enhance this difference. JF - 74th Annual Western Snow Conference T3 - Proceedings of the 74th Annual Western Snow Conference PB - Western Snow Conference CY - Las Cruces, NM UR - sites/westernsnowconference.org/PDFs/2006LaMalfa.pdf ER -