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Fan Palm OasisVegetation
All natural or naturalized plant assemblages that include California fan palms are recognized as Palm Oasis habitats, cultivated stands of California fan palm are not considered Palm Oasis habitats. Densities of California fan palms vary from sparse scattered trees to dense, closely packed individuals. The vertical structure is usually well storied with fan palms towering over a subcanopy of smaller trees and large shrubs. California fan palms reach a maximum height of 25 m (82 ft). Grasses and shrubs may be found under relatively open canopies, although large stands generally have a sparse understory.
California fan palm is the dominant species in the canopy. Occasionally, fan palms are associated with coyote willow, velvet ash, California sycamore, and naturalized date palms. Fremont cottonwood, mesquite, and tamarisk may also be present. Subcanopy plants include arrowweed, squaw waterweed, alkali goldenbush, and young individuals of species in the overstory. Forbs and grasses include alkali sacaton and wiregrass.
California fan palms grow from seedling stage through young palm stage to mature trees. Only mature trees can reproduce. Most mature Palm Oasis habitats exhibit a relatively open canopy. Successful reproduction occurs after very wet winters. This response results in the "even aged" character of many palm oases. Reproduction may need to occur only once every 100 years in order to perpetuate Palm Oasis habitats.
Duration of Stages
The duration that a palm oasis persists as a particular successional stage is not clearly known, but seems to depend on the severity or frequency of fire. Fire is important for the reproduction and maintenance of Palm Oasis habitats
Fire opens up the understory, permitting fire-tolerant fan palms to become established. In addition, fire kills intolerant plants, such as mesquite, enhancing the water supply and releasing established shade-intolerant fan palms. As a result, palms grow very rapidly. Palm Oasis habitats are relatively long-lived; individuals may live for 200 years, though most probably die by year 150. Most oases exist as a mature stage often associated with a dense understory of younger palms.
Palm Oasis habitats are found adjacent to a number of other desert habitats including:
In many cases, characteristic plant species from these habitats comprise the understory of palm oases.
Many wildlife species (e.g., Gambel's quail, mourning dove, bighorn sheep) are attracted to Palm Oasis habitats because of the permanent or nearly permanent water supply. Further, the additional foliage complexity of tall trees with broad-leafed, dense canopies provides habitat not normally found in the short, shrubby creosotebush assemblages that dominate southeastern California. Species such as hooded oriole are partial to palms for nesting.
Palms are restricted to areas with permanent water or a water table that approaches the ground surface. Thus, Palm Oasis habitats generally occupy sites with moist alkaline soils near seeps, springs, and streams. The largest fan palm groves are along permanent streams or at large springs. Palm Oasis habitats are also found on hillsides or in canyons, arroyos, or washes. Many sites are adjacent to faulting activity, especially along the San Andreas Fault, where underground water frequently emerges. Hot, dry summers and cool, moist winters are characteristic. Summer temperatures are warm to hot. At the Oasis of Mara, mean temperatures for June through September range from 28 to 32 C (82 to 90 F). On only 29 days of the year does the temperature drop below 0 C (32 F). Precipitation generally occurs in winter, though summer storms originating in the Gulf of California may result in precipitation. Rainfall ranges from 8 to 15 cm (3 to 6 in per year. Potential evapotranspiration exceeds precipitation by 10 to 15 times.
Lost Palms Oasis
Lost Palms Oasis is a native fan palm oasis with over 110 palm trees. The trees are located in a deep canyon with steep walls of quartz monzonite. ...
Fan Palm Oases
There are 158 desert fan palm oases in North America. Five are located in Joshua Tree National Park. Oasis of Mara, Fan Palms, Joshua Tree National Park ...
Photos of 49 Palms
49 Palms Oasis Water rises into pools formed by large boulders in a steep and narrow canyon. Fan palm trees shade the pools as the water slowly slips ...
Oasis of Mara, 29 Palms, Joshua Tree National Park
Mammals of the Oasis · Reptiles of the Oasis · Cultural Landscape · Native American Life · The Old Well.
Common Plants of the Oasis - Oasis of Mara, 29 Palms, Joshua Tree National Park
The California fan palm (Washingtonia filifera) is a relic of a cooler, moister time. Today it is restricted to sites where ...
Oasis Plant Communities - Oasis of Mara
Biologists have defined three vegetative zones in fan palm oases: the hydric zone, the portion with standing water; the oasis ...
Oasis formation - Oasis of Mara, 29 Palms, Joshua Tree National Park
... Oasis Formation > The Oasis of Mara is near a scarp (steep slope) formed by action of the ...
Springs in the Mojave Desert
Springs & Oases 49 Palms Oasis - Joshua Tree National Park - South Mojave Desert · Saratoga Springs - Death Valley National Park - North Mojave Desert ...
Cottonwood Springs - Joshua Tree National Park, Colorado Desert
...Photo tour of Cottonwood Springs Oasis - joshua tree national park, mojave desert. ... cottonwood springs, oasis, desert vegetation, photos, fan palm, ...
Chemehuevis at Twentynine Palms
The Chemehuevis had lived at the oasis of Twentynine Palms many times before ... The water at the oasis permitted them to garden, and the surrounding area ...
Serrano Indians of the Mojave Desert
... the San Gabriel mountains to North Baldy (Mt Baden-Powell), south across the San Bernardino Valley and eastward to near 29 Palms and the Oasis of Mara. ...
49 Palms Oasis - Joshua Tree National Park
Fan palm oasis understory
Lost Palms Oasis - Joshua Tree National Park
Ibex Springs - Death Valley National Park
Oasis of Mara - Joshua Tree National Park