BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Pinus radiata | Monterey Pine 



GENERAL BOTANICAL CHARACTERISTICS : 
Monterey pine is a native, evergreen conifer.  It attains a height of
49.5 to 115.5 feet (15-35 m) and a d.b.h. of 24 to 36 inches (60-90 cm)
[43].  The outer bark is narrowly ridged and the inner bark is resinous
[33,43].  The needles occur in clusters of three and are 4 to 6 inches
(10-15 cm) long.  They persist for approximately 3 years [11,33,43].
Cones are 3 to 5.5 inches (7.5-14 cm) long and occur in one or more
clusters of three to five around the branch [16,33,43,54].  Monterey
pine lives a maximum of 80 to 90 years [49].

Monterey pine has a low frost tolerance [35].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
The minimum seed-bearing age for Monterey pine is between 5 and 10
years.  Maximum seed production beings at 15 or 20 years of age if trees
are open-grown, and later if stands are dense [11,25,35].  Cones are
produced annually, with good cone crops produced every other year [25].
Mature cones remain attached to the branch.  They may remain closed for
several years, depending upon temperature and humidity.  Cones open and
release seed during warm, dry periods and close rapidly when temperature
drops and relative humidity increases.  This results in a constant but
meager seed rain [52].  The cones of native populations open
infrequently because their habitat is typically cool and moist.
Seedfall is heaviest in warm, dry years [35].  Unreleased seed remains
viable for decades.  Seeds from cones up to 24 years of age have
germinated; however, germinative capacity appears to fall off with
progressing years [52].  Seeds can be exposed to a temperature of 203
degrees Fahrenheit (95 deg C) before germination is significantly
reduced [29].  Seedling recruitment is best on mineral soil [52].
Details of growth are discussed in the literature [11].

Monterey pine does not reproduce by sprouting [14,35].


SITE CHARACTERISTICS : 
The climate where Monterey pine occurs is humid with mild year-round
temperatures.  Winters are wet.  Rain does not usually fall in July and
August, but tree crowns collect moisture from summer fog moving inland
[35].  On Guadalupe and Cedros islands the climate is mediterranean
[23,35].

Soils in which Monterey pine grows are often deep, sandy loams with a
clay layer 20 to 33 inches (50-80 cm) below the surface.  Good sites
have a top layer of organic soil.  Soils are generally acidic [35].
Slopes are typically gentle and often north facing [35].


SUCCESSIONAL STATUS : 
Facultative Seral Species

Monterey pine normally invades dry sites with poor, shallow soils.  It
also invades oldfields after land clearance, grazing, fire, or logging
[48].  Trees establish in even-aged stands [52].

Monterey pine has intermediate shade tolerance [6,35].  As it matures it
becomes even less tolerant of shade, and shows optimal growth in full
sunlight [5].


SEASONAL DEVELOPMENT : 
Pollination occurs from January to February but may be extended due to
high temperatures [15,25,35].  Cones open and seeds are dispersed in the
first warm, moist days of late winter and early spring.  Cones may open
and close several times as moisture and temperature conditions fluctuate
[35].

Related categories for Species: Pinus radiata | Monterey Pine