Subsection M261Eu
Kern Plateau
This
subsection is a high plateau west of the main crest of the Sierra Nevada.
It is between the Kern Canyon Fault and the eastern slope of the Sierra
Nevada from near Golden Trout Creek south to South Fork Valley. The
higher part of the Scodie Mountains is included in this subsection.
It has a temperate to cold and semi-arid to subhumid climate. MLRA
22e.
Lithology
and Stratigraphy. Mesozoic granitic rocks predominate in
this subsection. Also, pre-batholith metamorphic rocks are moderately
extensive. Monache and Templeton Mountains are small Tertiary andesitic
cones. There are small Pleistocene basalt flows along Golden Trout
Creek and the South Fork of the Kern River and two cinder cones associated
with them. Quaternary alluvium is common in small areas along streams,
but Pleistocene glacial till is sparse.
Geomorphology. This subsection is characterized by
gentle to moderately steep slopes on a rolling plateau and steep to very
steep slopes in the canyon of the Kern River and on edges of the plateau.
The Kern River runs from north to south in nearly a straight line along
the Kern Canyon Fault. The plateau is not deeply incised, except
near the edge of it and along the Kern River. The subsection elevation
ranges from about 3000 or 4000 feet up to 11371 feet. Fluvial
erosion and deposition are the main geomorphic processes.
Soils. The soils are mostly Dystric Xeropsamments; Dystric
and shallow Typic Xerorthents; Dystric Xerochrepts; Typic, Ultic, Pachic,
and shallow Entic Haploxerolls; and, in the southeastern part of the subsection,
shallow Xeric Torripsamments, Torriorthentic Haploxerolls, and Aridic Argixerolls.
There are Andic Xerumbrepts and Typic Vitrandepts on the volcanic rocks
of Templeton and Monache Mountains. The soils are well drained.
Soil temperature regimes are mostly mesic and frigid. Soil moisture
regimes are mostly xeric, but some are aridic.
Vegetation. The predominant natural plant communities
are Jeffrey pine series, Mixed conifer series, and White fir series, and,
in the southeastern part of the subsection, Singleleaf pinyon series.
Canyon live oak series and Mixed chaparral shrublands occur on very steep
rocky slopes along the Kern River and the southern edge of the plateau.
Sedge meadow communities are common, but not extensive.
Characteristic series by lifeform include:
Grasslands: Ashy ryegrass series, Montane meadow habitat, Nebraska
sedge series, Needle-and-thread series, Rocky Mountain sedge series.
Shrublands: Brewer oak series, Chamise series, Deerbrush series,
Greenleaf manzanita series, Interior live oak series, Tobacco brush series,
Wedgeleaf ceanothus series.
Forests and woodlands: Birchleaf mountain-mahogany series, Canyon
live oak series, Foxtail pine series, Incense-cedar series, Jeffrey pine
series, Mixed conifer series, Singleleaf pinyon series, White fir series.
Climate. The mean annual precipitation is about 10 to 30 inches.
Most of the precipitation is snow at higher elevations. Mean annual
temperature is about 35° to 55° F. The mean freeze-free period
is about 25 to 150 days.
Surface Water. Runoff is rapid from most of the area.
It flows through the Kern River to a closed basin in the southern end of
the Great Valley. Maximum flow in the streams is during spring
when snow is melting rapidly. There are very few small natural lakes
or ponds in the subsection, but many on the same plateau further up in
the Kern River basin.