Programs and Projects
Maintaining Faunal Diversity in Forested Ecosystems of the Coastal and Intermountain West
REDWOOD EXPERIMENTAL FOREST AT YUROK
The 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).
The 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.
The 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.
The 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
Soil-vegetation maps are available for the general area.
Regeneration 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 Data
Stream reaches and distribution of fish species in High Prairie
Creek were mapped from 1984 to 1987.
EXAMPLES OF RESEARCH
- Salmonid preference for obstacle-formed pools
- Stream structure and fish production
- Ecology of old-growth forest wildlife habitat community
Commercial facilities are available in Crescent City and Klamath.
Timber Management/Wildlife Habitat Interactions in Northern California
Redwood Sciences Laboratory
1700 Bayview Drive
Arcata, California 95521-6098
Redwood Experimental Forest at Yurok is located on the coastal front
of the North Coast Ranges in Northern California, about 2.4 kilometers
inland from the Pacific Ocean and near the mouth of the Klamath
River, approximately at latitude 41 degrees 35 minutes North and
longitude 124 degrees 05 minutes West. Elevation ranges
from 40 to 340 meters.
The Experimental Forest is readily accessible from U.S. Highway
101, 27.2 kilometers south of Crescent City and 6.4 kilometers
north of Klamath.
Maps Available for Download