BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Pinus lambertiana | Sugar Pine 



GENERAL BOTANICAL CHARACTERISTICS : 
Sugar pines may live 400 to 500 years and are second only to giant
sequoia (Sequoia gigantea) in total volume.  A record sugar pine in
California measured 216 feet (66 m) tall and 122 inches (310 cm) in
d.b.h.  Trees up to 250 feet (76 m) tall and 10 feet (3 m) in diameter
have been reported.  Mature sugar pine cones are among the largest of
all conifers, averaging 12 inches (30 cm) in length, and can reach 22
inches (56 cm) long.  Its needles are 3 inches (7.5 cm) long and have
five to a cluster.  Sugar pines pyramidal crown has whorls of horizontal
branches with several conspicuously longer than others.  Its sap
contains a sugary substance [7,16,21].



RAUNKIAER LIFE FORM : 
   Phanerophyte: (Megaphanerophyte)
   Phanerophyte: (Mesophanerophyte)


REGENERATION PROCESSES : 
Sugar pine does not sprout, but young trees can be rooted from cuttings.
Its primary regeneration strategy is via seed [3,16].

Flowering and fruiting:  Sugar pine is monoecious.  Reproductive buds
are set in July and August, but are not discernible until late the next
spring.  Time of pollination ranges from late May to early August,
depending on elevation.  Female strobili are approximately 1 to 2 inches
(2.5-5.0 cm) long when pollinated and may double in size by the end of
the growing season.  Fertilization occurs the following spring,
approximately 12 months after pollination.  Dates of cone opening range
from mid-August at low elevations to early October at high elevations.
Sugar pine does not become a good cone producer until it has attained a
diameter of about 30 inches (75 cm) or is about 150 years old [2,16].

Seed production and dissemination:  Mature trees produce large amounts
of seeds, averaging up to 150 seeds per cone.  In good crop years, the
proportion of sound seeds is usually high (67 to 99 percent) but in
light crop years can fall as low as 28 percent.  Seed shed may begin in
late August at low elevations and at higher elevations is usually
complete by the end of October.  Seeds are large and heavy, averaging
2,100 seeds per pound (4,630/kg).  Seeds are not dispersed great
distances by wind, and 80 percent fall within 100 feet (30 m) of the
source.  Birds and small mammals aid in seed dissemination [16].

Seedling development:  Sugar pine seeds may lie dormant, but dormancy
can be broken by a 60 to 90 day stratification.  Fresh seed may
germinate with a 90 percent success rate if adequately ripened, cleaned,
and stratified.  Losses due to unprepared seedbeds, drought, insects,
and rodents may be high.  Germination is epigeal.  Seedlings rapidly
grow a deep taproot when seeds germinate on mineral soil.  Seedlings
will germinate on both litter and bare mineral soil, but development is
slow under shade conditions.  After 2 years, taproots range from 22 to
40 inches (56-102 cm) deep.  Planting sugar pine has met with some
failure.  A low drought tolerance may be the determining factor.  Sowing
stratified seed in February or March extends the growing season and
produces healthy seedlings of plantable size in one season [4,16].

Growth and yield:  Early growth of sugar pine is slow compared to
ponderosa pine but increases rapidly in the pole stage and continues
through maturity.  On favorable sites, growth increments in basal area
of 2.5 percent or more can be sustained for up to 100 to 150 years.  The
best growth can be found between 4,500 to 6,000 feet (1,370-1,830 m) in
the central Sierra Nevada, between the American and San Joaquin Rivers.
Sugar pine is semitolerant to shade and may exhibit poor growth if
seedlings are enclosed by brush.  Sugar pine is a deep-rooted species
that is not susceptible to windthrow [9,16,21].



SITE CHARACTERISTICS : 
Sugar pine is found on a variety of sites from moist, steep, north- and
east-facing slopes, to more mesic, south-facing slopes.  The fuels under
sugar pine are generally heavy with deep soils.

Climate:  Temperature and precipitation vary widely throughout the range
of sugar pine.  The general weather pattern consists of hot, dry 
summers and cool, wet winters.  Precipitation during July and August is
usually less than 1 inch (2.5 cm) per month and summertime relative
humidities are low.  Most precipitation occurs between November and
April, mostly in the form of snow at middle elevations.  Total
precipitation varies from 33 to 69 inches (83-173 cm) per year [16].

Soils and topography:  Soil parent material include rocks of volcanic,
granitic, and sedimentary origin.  Soils formed from peridotite or
serpentinite typically support sugar pine stands of inferior growth and
quality.  The most extensive soils supporting sugar pine are
well-drained, moderately to rapidly permeable, and slightly acidic to
neutral pH (7.0).  Best development of sugar pine is on mesic soils with
sandy to clayey loam textures.  Much of the terrain occupied by sugar
pine is steep and rugged.  Sugar pines are equally distributed on all
aspects at lower elevations but grow best on warm exposures as elevation
increases.  Optimum growth occurs on gentle terrain at middle elevations
[16].

Elevation:  Sugar pine ranges from near sea level in the Coast Range to
more than 10,000 feet (3,000 m) in the Transverse Range.  Elevational
limits increase with decreasing latitude.  Typical elevational ranges
are as follows [16]:
                   Cascade Range:  1,100 to  5,400 feet (335-1,645 m)   
                   Sierra Nevada:  2,000 to  7,500 feet (610-2,285 m)
         Sierra San Pedro Martir:  7,056 to  9,100 feet (2,150-2,775 m)
Transverse and Peninsular Ranges:  4,000 to 10,000 feet (1,220-3,000 m)



SUCCESSIONAL STATUS : 
Sugar pine is primarily an early-seral to seral species.  It is
rarely found in pure stands.  When sugar pine is found to be the dominant
species in old-growth stands, it most often was dominant to begin with
or released by natural causes.  White fir would usually be the climax
species in mixed conifer forest in the absence of any natural
disturbances.  When disturbance does occur, it creates gaps in which
sugar pine is well adapted to grow [3,4,16,25].



SEASONAL DEVELOPMENT : 
Seasonal growth durations of sugar pine at various elevations in the Sierra 
Nevada are as follows [11]:

                   Height           Radial
                   Growth*          Growth
                   ------           ------
Start (days)**       146              107
Start (date)       May 26         April 17
Length (days)         51              129
Rapidity (days)       15               46

* An 8-year average.
** Number of days from January 1.

Related categories for Species: Pinus lambertiana | Sugar Pine