405 m Flux Tower, San Joaquin Experimental Range

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The SJER flux tower is in the oak woodlands of the foothills at 400 m in elevation. The primary landuse at the San Joaquin Experimental Range is cattle grazing.

513 mm   Precip

Parent Field Area:
Flux Towers Transect ▲


igneous-felsic intrusive

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Setting & Research
Dynamic Map
Partner Organizations
  • Setting & Research

    The SJER vegetation community is mostly blue oak (Quercus douglasii), interior live oak (Quercus wislizeni), gray pine (Pinus sabiniana), California Buckeye (Aesculus californica), poison oak (Toxicodendron diversilobum) and many species of naturalized annual grasses and native grasses and forbs. Elevation of the tower is 405 m. Mean minimum T is 9.3ºC, mean maximum temperature is 23.5ºC. Mean annual precipitation is 513 mm year-1. (information from Goulden et al., 2012).

    Panorama of San Joaquin Experimental Range. May 2014.

    A full size image is available at the digital library.

    For additional information, see Goulden et al., 2012.

    This flux tower is part of a larger transect: SJER (405 m); Soaproot Saddle (1160 m); P301 (2015 m); Short Hair Creek (2700 m)

    Panorama of San Joaquin Experimental Range. May 2014.

    A full size image is available at the digital library.

  • Dynamic Map

    To fully zoom into a small area, you may need to visit the "Map" button and uncheck "Terrain" view.

  • Data

    Flux Tower Transect, SJER - Flux Tower, Meteorology (2009-2016)
    7 components    405 m Flux Tower, San Joaquin Experimental Range    Biology / Ecology, Climatology / Meteorology    Mike Goulden, Anne Kelly

  • Photos

    SSCZO - Flux Towers

    An eddy covariance flux tower is located near the top of the P301 watershed. Instruments collect data on temperature, relative humidity, and fluxes of carbon dioxide and water vapor to determine the physiological responses of the site (for example, how photosynthesis increases with light) and summed over a year to determine the carbon balance of a site (how much carbon it is gaining or losing). Three other flux towers have been instrumented at different elevations with the Sierras including the San Joaquin River, Soaproot, and Short Hair Creek.

    This west-east transect spans elevation gradient from 400 m to 2700 m. The change in elevation is accompanied by a slight increase in precipitation, but the main change is a shift from rain-dominated precipitation to snow-dominated precipitation. The climatic shift plays out in other ways as well. At lower elevations, high temperatures and low water availability limit evapotranspiration by vegetation. Meanwhile, forest activity (evapotranspiration) at higher elevations is limited by cold winter temperatures. There is a sweet spot at middle elevations of yera-round evapotranspiration and forest activity.

    Photo galleries of each flux tower are available: San Joaquin Experimental Range;  Soaproot SaddleProvidence subcatchment P301; and Short Hair Creek.

    SSCZO - SJER field area

    This gallery showcases the landscape, vegetation, equipment and facilities at the SJER field area. 

  • Partner Organizations

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  • Geology

    • igneous-felsic intrusive

    SJER – 400 m elevation
    Quad: Millerton Lake

    Ward Mountain Trondhjemite (Kw) (formerly Leucotonalite of Ward Mountain)
    “Medium- to fine-grained biotite leucotonalite (trondhjemite). Rock appears gneissic in outcrop and deformed and recrystallized in thin section... Biotite, generally in tiny plates, is the sole primary mafic mineral. Secondary muscovite in plates as much as 2 mm across is abundant locally... U-Pb age of … 115 m.y” (Bateman and Busacca 1982). “Biotite averages about 10 percent of the rock… most samples contain less than 5 percent alkali feldspar… Deformed trondhjemite, which constitutes the bulk of the rock, is fine grained and gneissic, and when viewed in thin section it can be seen to have a granoblastic texture… The Ward Mountain Trondhjemite intrudes the Bass Lake Tonalite” (Bateman 1992).

    For more detail on the other flux towers, refer to each page:

    Soaproot Saddle, 1100 m elevation
    Quad: Shaver Lake
    Bass Lake Tonalite (Kbl, formerly Tonalite of Blue Canyon)

    P301, 2000 m elevation
    Quad: Huntington Lake
    Dinkey Creek Granodiorite (Kdc, formerly Granodiorite of Dinkey Creek)

    Short Hair Creek, 2700 m elevation
    Quad: Blackcap Mountain
    Aplite and felsic quartz monzonite dikes (Kap)
    Granodiorite of Dinkey Creek (Kdc, see description for P301)