| Area: |
1,121 ac (454 ha) |
| Elevation: |
6,890 to 7,610 ft (2,101 to 2,321 m) |
| Vegetation: |
Ponderosa Pine |
| Parent Material: |
Basalt |
| Years: |
1957 - 1976 |
| Treatment: |
Regular One-third Strip-cut |
| Year Treated: |
1967 |
|
Regular strip cut
Aerial view of regular strip cut 60' wide, 120' long
|
| Objective: |
To determine how a strip-cut treatment of ponderosa pine affects streamflow, erosion and sedimentation, vegetation, and wildlife. Prior to treatment, streamflow from WS 9 was calibrated against streamflow from the designated control WS 8. Watershed 8 was treated in 1974 eliminating its further use as a control for evaluation the WS 9 treatment. |
| Treatment: |
On Watershed 9, uniform strips 18 m (60 ft) wide were cut from the forest in 1967. The total area cut equaled one-third of watershed. These strips were oriented downslope to direct surface runoff into drainage channels. Harvest slash was piled in these aisles and partially burned. The strips of remaining forest, average 36 m (120 ft) wide, were undisturbed (Brown et al. 1974). |
| Response: |
The average annual water runoff increased by 25 mm (1 inch) for 6 years - up 15 % (Baker 1986). Additional analysis of streamflow was terminated because the control watershed (WS 8) was treated in 1974. Volumes of sediment removed from the watershed have been minor.
Forage preferred by livestock and by deer and elk was scarce before harvesting. Though production has increased 40 % for livestock and 100 % for big game since treatment, total forage levels remain low. Consequently, increases in deer and elk use have been slight.
If this experimental management method were to be permanently maintained, strips covering one-third of the watershed would be harvested every 40 years, with each set of strips reharvested on a 120-year cycle. |
| 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. |
|
|
