Name:
Quercus agrifolia - Quercus lobata - Umbellularia californica Forest & Woodland Group
Reference:
NatureServe Biotics 2019
Description:
This group consists of oak and other broadleaf woodlands largely endemic to the California Floristic Province. It forms one of the most extensive and conspicuous vegetation types in California. Anchored by six endemic, widespread and overlapping characteristic oak species which are (in alphabetical order): <i>Quercus agrifolia, Quercus chrysolepis, Quercus douglasii, Quercus kelloggii, Quercus lobata</i>, and <i>Quercus wislizeni</i>. These occur throughout California on coastal plains, in the coastal mountains from north to south, in the foothills surrounding the Central Valley, in the Sierra Nevada foothills up to 2000 m (rarely as high as 2500 m [8200 feet]) elevation, in the Klamath Mountains of the northwest, in the Peninsula Ranges in the south, as well as on the Channel Islands. <i>Quercus wislizeni</i> intermixes extensively with <i>Quercus douglasii</i> throughout almost all of its range. The same is true with <i>Quercus lobata</i> and <i>Quercus douglasii</i> or <i>Quercus wislizeni</i>. <i>Quercus lobata</i> and <i>Quercus wislizeni</i> may both be found in riparian or semi-riparian settings, and <i>Quercus lobata</i> is often found in mountains and foothills at higher elevations than <i>Quercus douglasii</i> in the foothills and Coast Ranges. On the Channel Islands, there are several island endemic broadleaf tree species; however, these are associated and intermix with non-island endemics, for example <i>Lyonothamnus</i> spp. and <i>Quercus tomentella</i> are often associated with <i>Quercus agrifolia</i> and are clearly ecologically related to them. Although <i>Umbellularia californica</i> is typically more mesic than many oaks, it is regularly associated with <i>Quercus agrifolia</i> in the Coast Ranges and with <i>Quercus chrysolepis</i> in the Klamath Mountains, in the Sierra Nevada and the southern California mountains. The "mixed" oak alliance (<i>Quercus agrifolia, Quercus douglasii, Quercus kelloggii, Quercus lobata</i>, and <i>Quercus wislizeni</i>) is another example of why a split between evergreen and deciduous species or montane versus lower-elevation types cannot represent the ecology of these woodland communities. There are many stands in the Coast Ranges and other parts of the state where two or more species of evergreen and deciduous oaks codominate.<br /><br />The species with the widest range is <i>Quercus chrysolepis</i>, ranging up into central Oregon and east into Arizona. Looking at association-level diversity, these stands are primarily in the California Floristic Province. <i>Quercus chrysolepis</i>-dominated stands are clearly associated with warm California Mediterranean climate and are regularly associated with <i>Quercus kelloggii, Aesculus californica</i>, and <i>Quercus wislizeni</i> throughout much of the state. Thus, although <i>Quercus chrysolepis</i> and <i>Quercus kelloggii</i> are often considered more "montane" than other California oaks, they overlap extensively with other oaks in the Sierra Nevada foothills and in the Coast Ranges. Similarly, <i>Quercus douglasii</i> and <i>Quercus wislizeni</i>, a deciduous and an evergreen oak, respectively, are the most commonly overlapping species in the warmer inland foothills surrounding the Great Valley.<br /><br />In addition, in southern California, in the Peninsular Ranges, <i>Quercus engelmannii</i> occurs and mixes with several of the above-mentioned species. Also included in this group are distinctive woodlands of other California endemic broadleaf tree species that occur as pure stands adjacent to oak woodlands, but also commonly are components of oak woodland canopy. These are <i>Aesculus californica, Juglans californica</i>, and <i>Umbellularia californica</i>.<br /><br />These woodlands vary in density from open savannas, moderately closed woodlands to closed canopy forests. In some cases, oak woodlands are of a single oak dominance by <i>Quercus douglasii, Quercus lobata, Quercus agrifolia, Quercus kelloggii, Quercus chrysolepis</i>, or <i>Quercus wislizeni</i> trees that are scattered across the landscape, and in other cases, trees of mixed composition form a closed tree canopy. They share strong adaptation to dry summers and relatively warm rainy winters, characteristic of the Californian Mediterranean climate.
Accession Code:
urn:lsid:vegbank.org:commConcept:39996-{0F63079B-4464-4DC4-99CA-ED90B9E580F6}
Plot-observations of this Community Concept:
0
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