BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Juniperus californica | California Juniper 



GENERAL BOTANICAL CHARACTERISTICS : 
California juniper is a native conifer that is adapted to xeric sites
[35,36].  As a seedling under 12 inches (30cm) in height, it is shade
dependent [24].  Its growth is crooked, forked, and multistemmed [6].
Its branches are stiff with irregular stems [25].

Its scalelike leaves are denticulate at the margins, glandular, pitted
on the back, and bluntly pointed [22,25].  The leaves occur in whorls of
two.

At maturity, California juniper reaches 3 to 15 feet (1-4.5 m),
occassionally reaching 40 feet (12 m) in height [19,25,31].

Each fruit contains one to two seeds, and the ripe berries are reddish
brown [19,25].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
California juniper seeds are dispersed by birds and mammals, which eat
the berries and then excrete viable, scarified seeds [24].  Minimum
seed-bearing age is not reported [19].


SITE CHARACTERISTICS : 
California juniper most commonly occurs in pinyon-juniper woodlands that
border and integrate with chaparral along desert margins [14,24].  This
woodland type also occurs with montane forest elements, with Joshua tree
woodland, and with coastal sage scrub [14,15].  California juniper is a
dominant species in desert chaparral [14].

California juniper occurs in a climate that has mild, moist, sunny
winters and hot, dry summers.  Most precipitation falls between December
and April, with annual precipitation ranging from less than 12 to more
than 40 inches (300-1,000 mm) at higher elevations [14,26].  Winter
temperatures range from 25 to 65 degrees Fahrenheit (-4 - 18 deg C), and
summer temperatures range from 55 to more than 100 degrees Fahrenheit
(12-38 deg C).  The growing season of California juniper is 340 to 360
days [14].

Soils of chaparral are porous, rocky, coarse, and sandy or silty.  These
soils are low in clay and in nutrients in comparison to agricultural
soils.  These soils are also very shallow [14].  California juniper also
occurs on alluvial fans and steep slopes [14,15,38].  

The altitude at which California juniper occurs varies as follows
[5,15,26]:

Location                      Feet            Meters
Christmas Tree Pass, NV    3,220-4,020        975-1,218     
Sonoran Desert, CA         3,500-10,000       1,060-3,030
San Beradino and 
San Gabriel Mountains, CA  3,000-9,000        900-2,700

California juniper is most commonly associated with singleleaf pinyon.
Associates other than those previously mentioned vary between habitats.
Montane conifer forest associates are mentioned in the Distribution and
Occurrence frame.  Pinyon-juniper woodland associates are
mountain-mahogany (Cercocarpus spp.), bitterbrush (Purshia spp.),
snakeweed (Gutierrizia brecteata), narrowleaf goldenweed, and California
buckwheat (Eriogonum fasciculatum) [15,38].  Desert edge and chaparral
associates include oaks (Quercus spp.), blackbrush (Coleogyne
ramosissima), creosotebush (Larrea divaricata), chamise (Adenostoma
fasciculatum), manzanita (Arctostaphylos spp.), ceanothus (Ceanothus
spp.), birchleaf mountain-mahogany (Cercocarpus spp.), desert
bitterbrush (Purshia glandulosa), Dorrs sage (Salvia dorii), and
cliffrose (Cowania spp.)  [15,26,31,38].


SUCCESSIONAL STATUS : 
Obligate Climax Species

Mature California juniper is not shade tolerant.  Seedlings, however,
appear to be shade dependent, possibly because these seedlings will
replace the juniper they grow up under [24].  In the absence of
disturbance (fire or other), junipers tend to replace themselves as
mature stands gradually die out [31].  Severe fires result in
elimination of nonsprouting junipers, such as California juniper, and
favor fire-adapted species of desert chaparral [15,18].  On rocky breaks
where it is protected from fire, California juniper is a climax species,
but in grasslands frequently disturbed by fire, California juniper is
not a climax species [39].


SEASONAL DEVELOPMENT : 
Despite a growing season that is between 340 and 360 days, height growth
of dominant juniper trees is only 2 to 4 inches (5-10 cm) per year and
diameter growth only 0.04 to 0.2 inch (1-5 mm) per year [24].  Water is
the growth-limiting factor; tree age is not a major influence on the
growth rate [24].

California juniper flowers in the spring [19,25], and seeds germinate in
early spring [22].

Related categories for Species: Juniperus californica | California Juniper