BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Pinus torreyana | Torrey Pine 



GENERAL BOTANICAL CHARACTERISTICS : 
Torrey pine is a native, slow-growing tree endemic to California
[25,30].  It grows from 25 to 60 feet (7.5-18 m) tall, but is usually
around 40 feet (12 m) in height [17,33].  The mature crown is open and
rounded with many large branches [14].  The needles are in fascicles of
5 and are 8 to 12 inches (20-30 cm) long [16].  The bark is rough and
flaky [16].  Cones are large, 4 to 6 inches (10.2-15.2 cm) wide, and
long.  They are harder and heavier than most other pine cones [33].
Torrey pine taproots may reach 25 feet (7.5 m) into sandstone, and
lateral roots can extend up to 225 feet (67.5 m) from the trunk [9].
The oldest Torrey pines are about 150 years old [21].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Torrey pine regenerates sexually.  It does not reproduce naturally by
vegetative methods.    

Seed production and dissemination:  Torrey pines begin to produce seed
when they are 12 to 18 years old.  Torrey pine exhibits delayed seed
dispersal, a pattern of seed release intermediate between open- and
closed-cone species.  In the TPSR, Torrey pine cones begin to open when
seeds are mature, but seed fall continues for up to 13 years after cone
maturity.  Over 76 percent of available seeds were in cones 1 or more
years after seed maturity [27].  Seed release accelerates through the
fourth year when cones retain 22 percent of seeds, and then levels off
or slowly declines [27].  Over 15 percent of the original seed is
retained 11 years following cone maturity [26].  At age 14, cones are
mostly open but still retain about 10 percent of seed [14].  Torrey
pines on Santa Rosa Island may release seed more rapidly than those in
the TPSR [26].

Seed viability decreases with cone age, but seeds at least partially
exposed for 10 years remain viable [27].  Predispersal loss of seed is
high in Torrey pine.  Before dispersal, 6.8 percent of seed is lost to
arthropod seed predators within the cone and 4.6 percent of seed has
already germinated.  Germination of seed in the cone is unique to Torrey
pine in the genus Pinus [26,27].  The seed of Torrey pine is nearly
wingless; wind dispersal is negligible.  Birds such as scrub jays aid in
seed dissemination [9,20].   

Seedling development:  Cold stratification periods of 30 to 90 days at
33 to 41 degrees Fahrenheit (.56-5 deg C) are recommended for rapid and
complete germination [17].  Seedling mortality is largely a function of
water stress and is highest in July and August.  Seedling establishment
increases with disturbance such as fire.  Very few seedlings are
currently survive to reproductive age [26].


SITE CHARACTERISTICS : 
Torrey pine has adapted to a harsh environment of poor soils and little
moisture [33].  The climate is maritime with low winter rainfall and
frequent fog [40].  The species occurs in scattered groves or is widely
dispersed on ridgetops, slopes, and gullies.  It is also found in
coastal highlands, canyons, and mesas [4,16].  It grows in open,
shallow, humus-poor, sandy soils [33,40].  Torrey pine is found at
elevations of 200 to 500 feet (60-150 m) [13].


SUCCESSIONAL STATUS : 
Facultative Seral Species

Torrey pine is shade tolerant.  Approximately 90 percent of Torrey pine
seedlings are found under adult trees [26].


SEASONAL DEVELOPMENT : 
Torrey pine is monoecious.  Cones are pollinated from January to March
and reach maturity in the summer two and a half years later [26].  Cone
opening initiates when seeds are mature [14].  Seed dispersal begins in
September after cone-ripening [16,17].  
  

Related categories for Species: Pinus torreyana | Torrey Pine