Teakettle Experimental Forest

Climate

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 mm/yr.

Differences in soil surface temperatures are strongly influenced by vegetation patch size and high summer temperature, even at 2,000 m in elevation. In open-canopy areas, July surface temperatures can reach 60 °C, whereas 10 m away in closed-canopy forest, the temperature is 28 °C.

Soils

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.

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 shallow soils.

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

Research, Past and Present

Through the 1970s, data on water flow 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.

Collaborators

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.

Research Opportunities

There is a wealth of fundamental ecological data at the 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.

Long-Term Databases

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.