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Water From Colorado's Bark Beetle Forests -Project Overview <br />Elder, Rhoades & Hubbard; USFS Rocky Mountain Research Station; 5/15/08 <br />and snow retention (accumulation). We will measure both snow depth and snow water <br />equivalence (SWE): depth in high-resolution transects since depth has greater variance, <br />and SWE at a reduced number of points since it varies less and is more labor intensive to <br />measure. Conventional statistics and spectral analyses will be used to relate roughness to <br />snow accumulation within and between treatment plots. <br />We will assess treatment differences in volumetric soil moisture and temperature using a <br />combination of point sampling and continuous monitoring. Point measurements of soil <br />moisture and temperature will be gathered monthly during the growing season on all 32 <br />treatment plots. We will measure soil moisture and temperature in the upper 10 cm of the <br />soil using portable soil moisture (Campbell Scientific, CS 620) and temperature probes <br />(Fluke Inc. Model 54). Soil moisture data collection will also be calibrated with a <br />transportable nuclear probe (Troxler 3440). Moisture and temperature measurements will <br />be taken at ten locations along sample transects. To supplement these measurements we <br />will install data loggers to monitor hourly air temperature, and soil moisture and <br />temperature (Hobo Weather Stations, Onset Inc. Model H21-001) throughout the growing <br />season. Data loggers will be installed beneath dead overstory and adjacent logged areas. <br />Each weather station will measure soil temperature (12 bit temperature sensor, Onset <br />Inc.) and moisture (ECH2O, Onset Inc.) in the upper 10 cm of mineral soil at four <br />locations equidistant from the plot center. Changes in daily soil temperature and <br />moisture for all plots and treatment combinations will be modeled using correlations <br />between point measurements and continuously monitored plots. <br />Water Quality <br />Inhigh-elevation watersheds of the Rocky Mountains >95% of snowmelt water infiltrates <br />through soils and moves along shallow groundwater flowpaths before merging with <br />stream water (Troendle and Reuss 1997), so the chemical composition of surface water of <br />is tightly linked to forest soil and vegetation. To characterize changes in water quality <br />associated with mountain pine beetle and forest management we will combine <br />measurements of surface water, soil nutrient movement and soil erosion. Physical soil <br />disturbance will be characterized before and after implementing harvesting treatments by <br />measuring the extent of various disturbance types/lntenSltleS along linear sample <br />transects. Pre- and post-treatment soil compaction measures will include soil strength <br />using a cone penetrometer (Rimik Electronics, CP40 II) and bulk density using adouble- <br />cylinder, hammer-driven core sampler designed to sample with minimal disturbance <br />(Giddings Machines Co.; Blake and Hartge 1986). The presence of surface erosion <br />indicators will be compared to pre-harvest conditions. We will measure changes in both <br />nitrate production and movement in our assessment of possible treatment implications on <br />water quality, though these fluxes have not been shown to reach ecologically harmful <br />levels following subalpine forest management (Brown and Binkley 1993; Reuss et al. <br />1997). On Colorado State Forest and Fraser Experimental Forest harvest areas, we will <br />compare post-treatment surface water with pre-outbreak stream water nutrients, <br />chemistry and suspended sediment.