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Programs and Projects(RWU-4251)Maintaining Faunal Diversity in Forested Ecosystems of the Coastal and Intermountain WestREDWOOD EXPERIMENTAL FOREST AT YUROKThe Redwood Experimental Forest at Yurok was established in 1940
to study the silviculture of coast redwood (Sequoia sempervirens)
and to develop techniques for regeneration and management. The
Experimental Forest includes 379 hectares drained by High Prairie
Creek. Redwood is the principal forest species on the forest with
Douglas-fir (Pseudotsuga menziesii), Sitka spruce, (Picea
sitchensis), western hemlock (Tsuga heterophylla),
and Port Orford-cedar (Chamaecyparis lawsoniana) making
up the remainder. About 59 percent of the timberland is classified
as Site I; 35 percent is classified as Site II. Tree ages range
up to 1200 years. Topography varies considerably over the forest.
Slopes range from 0 percent to greater than 75 percent. About 45 percent of the total area (226 ha out of 502 ha) was clearcut in harvest units ranging from 1.2 to 62.7 hectares between 1956 and 1985. About 1 percent (4 ha) was harvested in 1981 using the selection system. An additional 23 percent (87 ha) is available for approved manipulative research studies and 16 percent (61 ha) is preserved in an undisturbed old-growth redwood forest condition in the Yurok Research Natural Area, established in 1976. An ecological survey was conducted for the Research Natural Area (Taylor 1982). CLIMATEThe climate is typically mild and foggy in summer. The average July temperature is 12.6 degrees C, with little precipitation other than fog drip. The average January temperature is 6.8 degrees C. Annual rainfall averages 1933 millimeters and snowfall is uncommon. No climatic data are maintained at the Experimental Forest, but data are available from the town of Klamath, in a similar climatic environment 6.4 kilometers south, and from Crescent City, 27.2 kilometers north of the Forest. Precipitation is well in excess of potential evapotranspiration, except for about a month in midsummer. SOILSThe entire region is underlain by Mesozoic rocks of the Franciscan Formation, a complex of raw to slightly metamorphic sedimentary rocks. This formation is generally soft and easily weathered, so that soil development is good, with unweathered regolith at depths of about 3 meters in most areas. Rock outcrops are few and, where they do occur, shallow soils and exposure combine to make such sites ecologically unique. The major soil series is Melbourne, with a small amount of Hugo Series along the ridge tops (about 6.5 ha) and Atwell Series at the lower elevations on the southern part of the Forest (about 2.0 ha). Unclassified alluvial soils are found along High Prairie Creek on a total of about 32.4 hectares. MAIN COMMUNITIESThe Yurok Research Natural Area supports very dense stands of old-growth redwood averaging about 200 square meters of basal area per hectare. The two dominant vegetation types on the forest are Sequoia sempervirens-Polystichum munitum and Alnus rubra-Rubus spectabilis. DATA BASESMaps Soil-vegetation maps are available for the general area. Timber DataRegeneration after cutting, young stand growth and yield, response to thinning, and redwood sprout development were recorded intermittently between 1956 and 1982. Post-harvest regeneration and effects of shelterwood removal were recorded between 1970 and 1985. Wildlife Habitat Data Data are available on species composition and abundance of vertebrate communities in response to changes in age, moisture, and structural features of forest stands from 1983 to 1985. Fish Habitat DataStream reaches and distribution of fish species in High Prairie Creek were mapped from 1984 to 1987. EXAMPLES OF RESEARCH
FACILITIES
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![[USDA Forest Service]](images/yurok1.gif)
![Yurok3 Map](../../wildlife/yurok/images/yurok3w2.gif")
