BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Pinus contorta var. murrayana | Sierra Lodgepole Pine 



GENERAL BOTANICAL CHARACTERISTICS : 
Sierra lodgepole pine is a native conifer from 90 to 100 feet (28-30 m)
in height and averaging 16.5 inches (42 cm) in d.b.h. [38,41,55,64].
Trees growing near timberline are shrubby in form [12].  Sierra
lodgepole pine is long-lived; some trees have lived in excess of 600
years [64].  Its bark is thin [39,41].  The branches are short and
finely subdivided into branchlets of small diameter [62].  Needles are
from 1.2 to 2.4 inches (3-6 cm) long and occur in fascicles of two
[29,41].  The nonserotinous cones are 1.6 to 2.4 inches (4-6 cm) in
length, and often occur in clusters [12,27,29,62,65].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Sierra lodgepole pine is prolific, reliable seed producer, with good
seed crops occurring every 1 to 3 years [12,27,34,55].  Cones first
appear between the ages of 4 and 8 [13,34].  The percentage of viable
seed is high.  Germination studies have shown that seed viability is
between 75 to 77 percent in southern Oregon and 72 percent in the Sierra
Nevada [13].  Seeds are wind dispersed and fall approximately 200 feet
(60 m) from the source [13].  They have remained viable for up to 17
years in cold storage [34].  Seeds require a minimum of 20 percent full
sunlight to germinate [13,39].  Bare mineral soils or disturbed duff
that is free of competing vegetation have the highest rates of
germination [55].  A study in the central Sierra Nevada showed that
Sierra lodgepole pine establishes in large numbers in localized areas of
disturbance, such as tree-fall sites [43].

In the southern Cascade region, squirrels may cause significant cone
losses [12].  However, seed loss to birds and rodents does not greatly
affect Sierra lodgepole pine reproduction because of the heavy cone
crops and high germination capacity of seeds [55].  Browsing by elk and
deer is usually not a major cause of seedling mortality.  Grazing or
trampling by livestock can, however, result in some losses [39].  Gopher
herbivory also kills young seedlings [14].

Sierra lodgepole pine does not sprout from the root crown [55].


SITE CHARACTERISTICS : 
Sierra lodgepole pine grows in areas with cold, wet winters and dry,
warm summers [38,53].  In the southern part of its range, Sierra
lodgepole pine grows under xeric conditions [23,56].  Annual
precipitation ranges from 30 to 60 inches (750-1,500 mm), mostly in the
form of snow [48,52].

Sierra lodgepole pine thrives on a broad spectrum of soil types, from
water-logged organic soils to well-drained glacial outwashes [13,62].
It also grows in soils with underlying hardpan.  Soil parent materials
include pumice, ash, and granite [22,45,52,55].  Sierra lodgepole pine
most commonly grows in soils with a pH of 5.1 to 5.3 [45].  It cannot
tolerate soils approaching a pH of 8 [11].

Sierra lodgepole pine occurs from 5,000 to 11,600 feet (1,515-3,508 m)
in elevation in California and from 3,000 and 7,000 feet (910-2,130 m)
in Oregon [38,41,56].

Other canopy associates not mentioned in Distribution and Occurrence
include quaking aspen (Populus tremuloides) and western juniper
(Juniperus occidentalis ssp. australis) [40,48,57].  Sierra lodgepole
pine understory is sparse [48].  Associate understory shrubs include
birchleaf mountain-mahogany (Cercocarpus ledifolius), pinemat manzanita
(Arctostaphylos nevadensis), gooseberry currant (Ribes montigenum),
purple mountain heather (Phyllodoce breweri), bitterbrush (Purshia
tridentata), whitethorn ceanothus (Ceanothus cordulatus), bearberry
(Arctostaphylos uva-ursi), and western huckleberry (Vaccinium
occidentale) [3,33,48].  Herbaceous associates include sedges (Carex
spp.), bottlebrush squirreltail (Elymus elymoides), western needlegrass
(Stipa occidentalis), pinegrass (Calamagrostis rubescens), rockcress
(Arabis spp.), sulfur buckwheat (Erogonum umbellatum), and pussypaws
(Spraguea umbellata) [39,48,59].


SUCCESSIONAL STATUS : 
Facultative Seral Species

Sierra lodgepole pine establishes soon after disturbance and is
moderately shade tolerant [13,18,20,26].  It forms stable climax
communities in the zone just above red fir and white fir-mountain
hemlock forests [1,43,48].  It is dominant on more xeric or infertile
sites within the white fir-mountain hemlock forest [1,7,52], but is
generally a seral tree within that forest type [1].


SEASONAL DEVELOPMENT : 
Pollen is shed in June.  Fertilization occurs 13 months after
pollination, usually in June or July [12,13,55].  Cones open and
disperse seed from late August to mid-October, and do not persist on the
tree [12,13].

Related categories for Species: Pinus contorta var. murrayana | Sierra Lodgepole Pine