BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Torreya californica | California Torreya 



GENERAL BOTANICAL CHARACTERISTICS : 
California torreya is a dioecious native evergreen tree, typically from
16.5 to 90 feet (5-30 m) tall and 8 to 20 inches (20-51 cm) in diameter
[16,21].  A record tree growing near Fort Bragg measured 141 feet (43 m)
in height and 14.8 feet (4.5 m) in d.b.h. until cut by timber thieves
[17].  The crown is pyramidal to irregular in shape [10,19].  Needles
persist for many years.  The bark is thin, from 0.3 to 0.5 inch (0.8-1.3
cm) on mature trees [19].  Roots are described as "deep" [14].  The
large, heavy seeds are from 1 to 1.4 inches (2.5-3.0 cm) long, enveloped
by a drupelike aril [16,21].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Male California torreya bear their microsporophylls within strobili.  In
contrast, the ovules of female trees are not contained within strobili
but are solitary [16].  Male strobili begin growth the year prior to
flowering, while females trees develop ovules in one growing season
[21].  Torreyas are wind pollinated [16].  Male trees must normally be
within 75 to 90 feet (23-27 m) of female trees in order to effect
pollination [24].  Seed production is erratic.  Good seed crops may be
followed by crop failure the following year [10].  Seeds mature in 2
years [19].  Being heavy, seeds usually fall near the parent plant; wind
dissemination is rare [17].  Seed predation by Stellar's and scrub jay
is high [10].  Seeds require a 9- to 12-month stratification period
before germination [21].  In one study, seeds stratified for 3 months
before planting took an additional 9 months to germinate under
greenhouse conditions.  Ninety-two percent of seedlings germinated at
that time. [15].  Temperature regimes during the stratification period
were not noted.  Seeds sometimes germinate without stratification but do
so slowly [21].

Growth of trees in the understory is slow [10].  Sudworth [24] reported
trees from 4 to 8 inches (10-20 cm) in diameter were 60 to 110 years of
age, while those from 12 to 18 inches (30-46 cm) in diameter were 170 to
265 years old.  The growth rate needs further study, however, as rates
of over 1 foot (30 cm) per year have been reported in cultivars [3].
Preliminary data obtained from tree-ring counts of saplings on the El
Dorado National Forest shows some trees attained heights of 4.8 feet
(1.5 m) in 28 years [10].

California torreya sprouts from the roots, root crown, and bole
following damage to aboveground portions of the tree [3,10,19].  Some
torreyas reproduce by layering [21], but the layering capacity of
California torreya is unknown.


SITE CHARACTERISTICS : 
California torreya grows in diverse sites such as streambanks, shaded
slopes, hot dry canyons, canyon floors, and lowland flats [3].  Best
growth occurs on moist sites.  Trees in Colusa County grow in serpentine
soil [8].

The climate is mediterranean, characterized by hot, dry summers and
cool, wet winters.  Summer climate is moderated in the outer Coast
Ranges by cool marine air and fog [29].

California torreya grows at elevations from 3,000 to 7,000 feet
(914-2,134 m) [16].

Plant associations:  Common overstory associates not listed under
Distrubution and Occurrence include tanoak (Lithocarpus densiflora),
Oregon ash (Fraxinus latifolia), California bay (Umbellularia
californica), bigleaf maple (Acer macrophyllum), white alder (Alnus
rhombifolia), and bishop pine (Pinus muricata).  Understory associates
include cascara (Rhamnus purshiana), ceanothus (Ceanothus spp.),
manzanita (Arctostaphylos spp.), Pacific rhododendron (Rhodedendron
macrophyllum), California huckleberry (Vaccinium ovatum), California red
huckleberry (V. parvifolium), and Pacific bayberry (Myrica californica)
[12,28].


SUCCESSIONAL STATUS : 
Facultative Seral Species

California torreya is very shade tolerant [9] and is found in late seral
and climax communities [3].  Following disturbance such as fire or
logging, sprouts growing from surviving perennating buds appear in
initial communities [10].


SEASONAL DEVELOPMENT : 
Stamens and arils are produced from March through May [16,21].  Seeds
ripen from August until October and are released from September through
November [15,21,27].

Related categories for Species: Torreya californica | California Torreya