Results and Current Status
Results from the 3-stage removal of the forest overstory
on North Fork of Workman Creek indicated:
- Streamflow increased from both the moist- and dry-site treatments,
but not from the riparian areas.
- Evaluation of the treatments in 1979, after 13 years of data
collection, showed that the increases had remained stable (Hibbert
and Gottfried 1987).
- Winter stormflows responded less to treatment than summer stormflows,
although the actual volumes of winter runoff were larger (Hibbert
and Gottfried 1987).
- Sediment yield increases were low (Rich
et al. 1961). Most sediments moved during high-volume stormflows,
and most material originated from the channels and main logging
road (Rich
and Gottfried 1976).
South Fork of Workman Creek
Results from thinning the forest overstory to 40 ft2/acre on South Fork
of Workman Creek showed:
- Water yield increases, which remained constant for 13 years (Hibbert
and Gottfried 1987). Severe forest overstory removal (to 40 fl2/acre)
to encourage growth of the ponderosa pine forests is not recommended
for present day management. An adverse reaction of the public would
likely be created because of the esthetic of such a treatment and because
of the perceived influence such a thinning would have on other components
of the ecosystem.
- There was little effect on soil movement (Rich
1962, Rich
and Gottfried 1976). A wildfire on upper area of South Fork produced
the greates amount of soil disturbance.
Implications
Research on the Sierra Ancha Experimental Forest has contributed to the
knowledge base of hydrology, watershed management, and basic ecology for
over 65 years. These studies provided:
- Guidance for subsequent watershed research programs in chaparral
and mixed conifer forested ecosystems.
- Information on water yield responses to vegetation manipulation that
is useful to land managers and researchers.
- Research findings that continue to be implemented when designing
multiple resource ecosystem management treatments.
Current Status
Most of the hydrologic measurements on the Sierra Ancha Experimental
Forest were discontinued in the late 1970s and 1980s in response to a
shift in USDA Forest Service research priorities. Currently, only the
Upper Parker Creek weir, the Sierra Ancha weather station, and the USDA
Natural Resources Conservation Services snow measuring station are active.
Ecologically-oriented research continues to a limited extent.
Arizona State University entered into a lease agreement with the Forest
Service in 1983 to use the Parker Creek Headquarters complex. The experimental
forest and surrounding Tonto National Forest continues to be used for
faculty and graduate student ecological research and summer field classes.
The Parker Creek complex is used for Forest Service, University, and conservation
group meetings. The Sierra Ancha Experimental Forest has a tradition of
natural ecosystem ecology and management research and the potential for
future contributions.
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