| Area: |
455 ac (184 ha) |
| Elevation: |
6,790 to 7,296 ft (2,071 to 2,225 m) |
| Vegetation: |
Ponderosa Pine |
| Parent Material: |
Basalt |
| Years: |
1958 - 1982 |
| Treatment: |
Clearcut |
| Year Treated: |
1967 |
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Sediment instrumentation
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Aerial view of windrows to catch blowing snow
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Aerial view after treatment>
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| Objective: |
To determine how clearing a ponderosa pine watershed affects streamflow, erosion and sedimentation, vegetation, and wildlife. Prior to the clearing treatment, streamflow from WS 12 was calibrated against flow from the designated control WS 13. |
| Treatment: |
Watershed 12 was cleared of all trees in 1967. Logging slash and oaks not sold for firewood were piled in windrows. The windrows were positioned to trap blowing snow, much as snow fences do, and to shade snowdrifts until spring temperatures caused rapid melting, thereby improving the potential for increasing surface runoff. |
| Response: |
Many forest visitors protested the appearance of this treatment during the first years following harvest - the most severe applied to a pine watershed. However, it was needed to determine the maximum potential for increasing streamflow in the pine type and as a base for comparing other pine treatments.
As hopefully expected, average streamflow increased significantly - 61 mm (2.4 inches), or 41 % the first year after treatment. What was not expected was the rapid decline in response to an average of 30 mm (1.1 inches), or 18 % in year 7 when it became non-significant (Baker 1986). The amount of sediment carried by the runoff rose 200 % from an average of 45 kg per ha (40 pounds per ac) per year to 134 kg per ha (120 pounds per ac). Even so, this is not a surprising change considering the severity of the treatment (Brown et al. 1974).
Livestock forage improved considerably, averaging an additional 268 kg per ha (240 pounds per ac) annually. That's more than twice the level of the pretreatment condition. Deer forage increased 134 kg per ha (120 pounds per ac) - up 175 %, and deer use rose substantially.
Trees of commercial value no longer exist and will not reappear until long after a new generation of pines becomes well established. Meanwhile, noncommercial trees such as Gambel oaks are growing vigorously and providing abundant food and cover for wildlife. In time, the pine forest will return. Even now, an average of 135 pine seedlings per acre can be found growing throughout the area. |
| References: |
Baker, M.B., Jr. 1986. Effects of ponderosa pine treatments on water yield in Arizona. Water Resources Research 22: 67-73. Brown, H.E., M.B. Baker, Jr., J.J. Rogers, W.P. Clary, J.L. Kovner, F.R. Larson, C.C. Avery, and R.E. Campbell. 1974. Opportunities for increasing water yields and other multiple use values on ponderosa pine forest lands. USDA Forest Service, Research Paper RM-129. |
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