DISTRIBUTION AND OCCURRENCE
SPECIES: Quercus lobata | Valley Oak 



GENERAL DISTRIBUTION : 
Valley oak is endemic to California.  It is distributed from Shasta
County south through the Central Valley and lower-elevation foothills
and valleys of the Sierra Nevada and Coast Ranges to Los Angeles County
[34,71].  It also occurs on Santa Cruz and Santa Catalina Islands [46].


ECOSYSTEMS : 
   FRES20  Douglas-fir
   FRES21  Ponderosa pine
   FRES24  Hemlock - Sitka spruce
   FRES27  Redwood
   FRES28  Western hardwoods
   FRES42  Annual grasslands


STATES : 
     CA


ADMINISTRATIVE UNITS : 
     PINN  SAMO  WHIS


BLM PHYSIOGRAPHIC REGIONS : 
    3  Southern Pacific Border
    4  Sierra Mountains


KUCHLER PLANT ASSOCIATIONS : 
   K001  Spruce - cedar - hemlock forest
   K005  Mixed conifer forest
   K006  Redwood forest
   K009  Pine - cypress forest
   K010  Ponderosa shrub forest
   K011  Western ponderosa forest
   K026  Oregon oakwoods
   K029  California mixed evergreen forest
   K030  California oakwoods
   K048  California steppe


SAF COVER TYPES : 
   221  Red alder
   222  Black cottonwood - willow
   223  Sitka spruce
   232  Redwood
   233  Oregon white oak
   234  Douglas-fir - tanoak - Pacific madrone
   245  Pacific ponderosa pine
   246  California black oak
   249  Canyon live oak
   250  Blue oak - Digger pine
   255  California coast live oak


SRM (RANGELAND) COVER TYPES : 
NO-ENTRY


HABITAT TYPES AND PLANT COMMUNITIES : 
This species dominates two plant communities:  the valley oak woodland
and the valley oak riparian forest.  It is often the only tree in valley
oak woodland, which are composed of grassy savannas with large, widely
spaced oaks.  The valley oak woodland and the annual grassland are
closely associated, and together form a mosiac over portions of
California's low-elevation rangeland [41].  Historically, the associated
grassland was probably dominated by perennial bunchgrasses [37].  Valley
oak woodland, once extensive, has largely been cleared for farmland and
now occurs in scattered remnant patches.  Isolated trees are sometimes
found in cultivated fields [77].

Valley oak riparian forest occurs on levees and the highest parts of
floodplains [38,40].  Canopies are open to densely closed; shrub cover
may be as great as 70 percent [13].  Historically, these forests
extended 0.6 to 5.0 miles (1-8 km) on each side of major rivers [5,38].

Valley oak riparian forest merges with Fremont cottonwood (Populus
fremontii) riparian forest near waterways and with valley oak woodland
on upland sites [39].  In foothill oak (Quercus spp.) woodlands, the
valley oak phase merges with the California black oak (Quercus
kelloggii), coast live oak (Q. agrifolia), or interior live oak (Q.
wislizenii) phases [2].  Valley oak is an indicator of rich, deep
alluvial soils that comprise some of the most fertile farmland in the
world [41,62].

Publications listing valley oak as a dominant or codominant species in
habitat typings are as follows:

A classification system for California's hardwood rangelands [2].
Blue oak communities in California [3].
Association types in the North Coast Ranges of California [16].
Riparian vegetation and flora of the Sacramento Valley [17].
Oak woodland [31].
Vegetation and floristics of Pinnacles National Monument [35].
Terrestrial natural communities of California [39].

Related categories for Species: Quercus lobata | Valley Oak