_Pinus monophylla_
_Juniperus californica_
_Quercus dumosa var. turbinella_
_Purshia glandulosa_
_Fremontia californica_
_Cercocarpus ledifolius_
_Yucca Whipplei_
In the San Gabriel Mountains this association is limited to the desert
slope and reaches its lower limit at the bases of the foothills and
extends up to the lower edge of the yellow pine forests. The altitudinal
extent of the pinyon-juniper association is from roughly 4000 to 6000
feet elevation.
Several habitats are evident within the pinyon-juniper belt. On north
slopes in the upper part of this association, scattered stands of pinyon
pines are found with dense patches of scrub oak intervening, while on
other such slopes a dense chaparral is present, consisting primarily of
scrub oak, mountain-mahogany, and California slippery-elm. In this type
of chaparral several hundred trap nights yielded only two rodent
species: _Neotoma fuscipes simplex_ and _Peromyscus truei montipinoris_.
There are few pinyons on the south slopes, especially in the lower parts
of the association; many of these slopes are clothed with an open growth
of manzanita and yucca, while northern exposures there support mostly
scrub oak. Many of the flats of the pinyon belt are grown to basin
sagebrush.
Following is a list of the mammals taken in about 400 trap nights at one
locality in the pinyon-juniper association. The area supported a mixed
growth of pinyon, scrub oak, mountain-mahogany, and antelope-brush,
together with smaller brushy plants, and was at the head of Grandview
Canyon, at an altitude of roughly 5000 feet.