Castle Creek Watersheds

Treatments and Practices

The results from the moist-site cut on North Fork and the single-tree selection harvest on South Fork of Workman Creek indicated that even-aged management could maintain long-term timber production and improve water. The 2 Castle Creek Watersheds, East Fork and West Fork, were used to test this hypothesis.

Harvesting during treatment on West Fork of Castle Creek

In 1965, one -sixth of the area of the West Fork was harvested in irregular blocks fitted to stand conditions. The remaining area was placed into optimum growing condition by thinning and sanitation operations. The idea was to duplicate commercial forest management using a 120-yr rotation and a 20-yr cutting cycle. The harvest reduced watershed basal area from 135 to 63 ft2/acre. Harvest blocks were planted with ponderosa pine for adequate regeneration.

A debate concerning the impacts of aggressive fire suppression on forest health and the potential dangers of stand-replacing wildfires began in the middle 1970s. Forest history studies indicate that before fire suppression, most wildfires were surface fires that reduced fuel loadings, improved seedbeds, thinned advance regeneration, and retarded the establishment of shade-tolerant species. Managers attempting to reintroduce fire into the region's forests, often found it difficult because of heavy fuel buildups. Therefore, in 1981 a second watershed treatment was initiated at Castle Creek to test the effects of preharvest prescribed burning on water parameters.

The treatment was applied to the East Fork, which had previously served as the control watershed. Analyses of the data indicated that this approach was valid because the streamflow annual volume relationship between West Fork and East Fork had remained constant since 1967. The fire was ignited in November 1981 and burned about 503 acres or 43% of the watershed. Surface fuels were consumed, while the middle forest floor layer was only slightly charred and few downed logs were totally consumed. Changes in the residual stand were minimal and tree mortality was 1% of the basal area.

 
Views of mixed conifer type