In the 1930s, California state and federal agencies began exploring how the
Central Valley of California's water supply might be increased through management
of Sierra Nevada watersheds. In 1938, a 1,300-ha area surrounding Teakettle
Creek was designated the Teakettle Experimental Area and five drainages were
chosen for study. Stream-gauging stations and sediment basins were built in
the 1940s. The area is old-growth forest at 2,000 to 2,800 m elevation and consists
primarily of mixed-conifer and red fir forest common on the western slope of
the Sierra Nevada.
Climate at the Teakettle Experimental Forest is typical of the Sierra Nevada
range: hot, dry summers and mild, moist winters. Most of the annual precipitation
falls as snow between November and May, and snow accumulations generally persist
until late May or early June. Mean maximum snow depth is 114 cm, but ranged
from 24 to 241 cm over a 30-year period. Mean annual precipitation is 1,250
Differences in soil surface temperatures are strongly influenced by vegetation
patch size and high summer temperature, even at 2,000 m in elevation. In opencanopy
areas, July surface temperatures can reach 60 °C, whereas 10 m away in
closed-canopy forest, the temperature is 28 °C.
Teakettle includes some areas of metasedimentary and volcanic substrates, but
the majority of the forest consists of granitic soils common in the southern
Sierra Nevada. The most common soils, the Cannell and Cagwin series (Inceptisols
and Entisols, respectively), have a coarse sandy loam texture throughout the
profile and are highly permeable, with a relatively low water-holding capacity.
These poorly developed soils also have very low clay content, usually less than
5 percent. The amount of fine organic matter is distributed patchily and is
an important influence on water and nutrient-holding capacity in these coarse
soils. Soils with higher water-holding capacity or longer retention times may
have significant microsite differences in plant species composition and biomass.
Jeffrey pine, black oak, live oak, or manzanita usually occur where soil depth
is less than 50 cm. Where soils are 1 m deep, closed-canopy forest and mountain
whitethorn often dominate the vegetation.
Teakettle has four main forest types. Mixed conifer forest covers about 65
percent of the forest, predominantly between 1,900 and 2,300 m elevation. Jeffrey
pine (5.5 percent) is prevalent on shallow soil conditions within the mixed-conifer
type. Red fir (28 percent) dominates elevations above 2,300 m except for moist
locations where lodgepole pine (0.5 percent) is dominant. Within the mixed-conifer
forest there is a fine-scale mosaic of four patch types: closed canopy, shrub
patches dominated by mountain whitethorn, open gaps, and areas of rock and extremely
Long-Term Data Bases
Streamflow and sedimentation data from the Teakettle are available for 1958
to 1979. Bird-census data have been collected since 1997. A 5-year study of
snag distribution and turnover occurred from 1997 to 2001. In 1997, a long-term
permanent plot experiment was begun on 4-ha plots (18). Within these 72 ha,
all trees, snags, logs, and shrubs have been identified, tagged, and mapped.
Growth, mortality, and turnover rates will be followed over the next few decades.
Research, Past and Present
Through the 1970s, data on waterflow and weather conditions were collected
using the five gauged watersheds. In the 1980s and early 1990s, studies of songbirds
and snag dynamics were begun. In 1997, a large experiment began comparing the
effects of fire and thinning on the mixed-conifer ecosystem. More than two dozen
researchers are involved in assessing treatment effects on a range of ecological
variables, including forest and understory vegetation, regeneration, microclimate,
decomposition and respiration, invertebrates, soil nutrients and moisture, epiphytes,
and small mammals. Fire and thinning treatments were completed in 2001 and response
data are being collected for the next several years.
Major Research Accomplishments and Effects on Management
Information on stream flows and sedimentation rates gathered on the Teakettle
have been valuable for understanding regional climate effects on water production
for California's Central Valley. Research begun in the 1990s should provide
important information on the effects of fire and thinning on ecosystem function.
These restoration treatments are used by forest managers following a century
of fire suppression that has significantly altered western forest ecosystems.
Research collaborators have come from the following institutions and agencies:
California State University, Michigan Technological University, National Aeronautics
and Space Administration-Goddard Space Flight Center, Oregon State University,
University of California- Berkley, University of California, University of Maryland,
Universidad Metropolitana, University of Michigan, University of Nevada, University
of Washington, USDA Forest Service, Forest Inventory and Analysis Program, Sierra
National Forest, and Southern Research Station.
There is a wealth of fundamental ecological data at he Teakettle to build upon
for researchers interested in the effects of fire and thinning on ecosystem
function. In particular, the permanently tagged and mapped 72 ha of forest (>
40,000 trees), microclimate information, and the soil moisture, respiration,
and nutrient data. Sample points with 3 to 4 years of collected data are well
marked and mapped, making it easy for sampling at locations where other ecological
components have been measured.
Teakettle is located 80 km east of Fresno, California, between Yosemite and
King's Canyon National Parks. There is a bunkhouse cabin, dry laboratory, and
storage garage. The 1,300 ha are gated and relatively remote.
Lat. 36°58´ N, long. 119°1´ W
Teakettle Experimental Forest
Sierra Nevada Research Center
2121 2nd Avenue, Suite A-101
Davis, CA 95616
Tel: (530) 754-7398