Pinus sabiniana Douglas ex D. Don

gray pine
California foothill pine
foothills pine
bull pine

More info for the term: fresh

Gray pine is a drought-tolerant, native evergreen conifer. Mature
trees average from 40 to 80 feet (12-24 m) in height and from 12 to 36
inches (30-90 cm) in d.b.h. [38,40]. Trees usually maintain a pyrimidal
growth form until the pole stage. Mature trees typically have multiple
trunks [40]. Gray pine is self-pruning, and lower branches are often
a considerable distance above the understory [35]. Gray pine grows a
deep taproot where soil depth permits [4,40]. In hardpan soils, it
develops a spreading, shallow root system with a weak taproot extending
through the duripan [40]. The bark of young trees is thin [40], while
older trees have thick bark [35]. Needles grow from 8 to 12 inches
(20-30 cm) long and are shed every 2 to 3 years [39]. Gray pine's
heavily spined female cones are among the largest and most massive in
the genus. Fresh cones average from 0.7 to 1.5 pounds (0.3-0.7 k), and
may exceed 2.2 pounds (1 kg) [40]. The cones are typically from 6 to 12
inches (15-30 cm) long. They do not form an abscission layer and are
retained long after seeds are shed. The hard-coated, heavy seeds are
from 0.6 to 1.0 inch (15-25 mm) long and have short-winged seeds
[17,38,39]. The lifespan of gray pine is unclear because most older
specimens were cut by early settlers, but it is believed to be 200+
years [40].



Gray pine cones. Creative Commons image by Keir Morse.

More info for the term: forest

Gray pine is endemic to California. It is distributed from Siskiyou
County south through the foothills of the Klamath, Cascade, and Coast
Ranges and the Sierra Nevada to Ventura County [23,39,40]. Near its
southernmost Sierra Nevada limit, gray pine is absent from a 55-mile
(89-km) stretch between Kings River and the South Fork of the Tule River
[23].



Distribution of gray pine. 1971 USDA, Forest Service map digitized by Thompson and others [52].

More info for the terms: fire regime, moderate-severity fire, natural, prescribed fire, scarification, seed, severity

Fire is a natural component of the blue oak-gray pine community [1].
Historically, these woodlands burned at 15- to 30-year intervals [1].
Fires were typically intense but of light or moderate severity, with
vegetation and fuels extremely dry in summer [9,28]. Researchers at the
San Joaquin Experimental Range in O'Neals, California, noted fire
surface temperatures near woody vegetation of 1,200 degrees Fahrenheit
(650 deg C) in a blue oak-gray pine community with a mixed-grass and
sparse brush understory [28]. A prescribed fire in a blue oak-gray pine
community in Glenville, Kern County, generated subsurface temperatures
of 156 degrees Fahrenheit (69 deg C) at a depth of 2 inches (0.8 cm)
below ground [35].

Gray pine is highly flammable. The needles contain ether extracts
[5]. It is a heavy resin producer, with the wood, bark, cones, and
needle sheaths all containing pitch [35,40]. Congealed flows of resin
that have dripped from wounds are common on gray pine. Consequently,
it is susceptible to fire damage [40].

Gray pine has two adaptations which enable it to survive fire. First,
some large trees will withstand moderate-severity fire. Mature trees
with thick bark and self-pruned trunks are best able to avoid fatal
scorching [35]. Secondly, seed regeneration is favored following fire.
Fire creates a favorable bare mineral soil seedbed, and heat
scarification of the woody seedcoat increases germination rates [40].

FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find FIRE REGIMES".

More info for the terms: fire suppression, stand-replacing fire

Gray pine is increasing in blue oak-gray pine communities due to fire
suppression and lack of blue oak regeneration [14]. Rangeland managers
are reporting an increase of chaparral brush invading grassy
understories of blue oak-gray pine woodlands, also because of fire
suppression [8]. Timber species are invading the woodlands as well
[26]. Prescribed burning would help restore the blue oak-Digger pine
community to a more desirable species balance. Managers, however,
should be alerted to the regeneration capacity of blue oak ecotypes
within their area. See the blue oak FEIS write-up for further
information.

Fire managers recommend broadcast burning of blue oak-gray pine
woodlands in spring after grasses have dried, usually late May, or in
fall after the first rains. Fires are set with drip torches and
permitted to burn downslope. There should be little or no wind.
Recommended relative humidity range during spring is 30 to 35 percent;
recommended ambient air temperature is between 70 to 80 degrees
Fahrenheit (21-27 deg C). In fall, recommended relative humidity is 25
to 30 percent. Fall temperatures of 70 to 75 degrees Fahrenheit (21-24
deg C) are suggested [1].

If the woodlands contain a chaparral understory, upslope strip burning
during winter and early spring is recommended. At this time, chaparral
brush is fully green and grass shoots are from 2 to 3 inches (0.8-1.2
cm) high. Acceptable ranges of humidity are from 25 to 30 percent;
acceptable temperature ranges are from 70 to 75 degrees Fahrenheit
(21-24 deg C) [1].

Dwarf-mistletoe is eliminated from an infected area following a
stand-replacing fire [31].

Bark beetles (Arhopalus asperatus) have been observed attacking severely
scorched gray pine within hours following fire [45].

More info on this topic.

More info for the term: phanerophyte

Phanerophyte

Gray pine grows on exposed, dry, rocky slopes at elevations from 100
to 6,000 feet (30-1,800 m) [23,26]. The climate is Mediterranean, with
mild winters and hot, dry summers [35]. Annual mean precipitation is 21
inches (530 mm), ranging from 3 to 40 inches (76-1,000 mm) [6,40].
Eighty percent of precipitation occurs during winter and early spring.
Snow falls occasionally [35]. The annual mean temperature is 61 degrees
Fahrenheit (16 deg C), with maximum summer temperatures sometimes above
105 degrees Fahrenheit (41 deg C) [6,9]. Relative humidity is often 5
percent or lower in summer [9].

More info on this topic.

This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

233 Oregon white oak
234 Douglas-fir - tanoak - Pacific madrone
238 Western juniper
239 Pinyon - juniper
244 Pacific ponderosa pine - Douglas-fir
245 Pacific ponderosa pine
246 California black oak
247 Jeffrey pine
248 Knobcone pine
249 Canyon live oak
250 Blue oak - Digger pine
255 California coast live oak

More info on this topic.

This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

More info for the term: shrub

FRES20 Douglas-fir
FRES21 Ponderosa pine
FRES27 Redwood
FRES28 Western hardwoods
FRES29 Sagebrush
FRES34 Chaparral - mountain shrub
FRES35 Pinyon - juniper
FRES42 Annual grasslands

More info on this topic.

This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the terms: forest, shrub, woodland

K005 Mixed conifer forest
K006 Redwood forest
K009 Pine - cypress forest
K010 Ponderosa shrub forest
K011 Western ponderosa forest
K023 Juniper - pinyon woodland
K024 Juniper steppe woodland
K028 Mosaic of K002 and K026
K029 California mixed evergreen forest
K030 California oakwoods
K033 Chaparral
K034 Montane chaparral
K035 Coastal sagebrush
K038 Great Basin sagebrush
K048 California steppe

More info for the term: prescribed fire

Moderate-severity fire kills a substantial number of gray pine. The
prescribed fire in Glenville (see Fire Ecology or Adaptations) killed 83
percent of gray pine present. All surviving gray pine were large trees
[35].

More info for the term: seed

The blue oak-gray pine community is preferred habitat for black-tailed
deer, California quail, and mourning dove [9]. Gray pine seeds are an
important diet item for various birds and rodents. Scrub jay, acorn
woodpecker, and California gray squirrel are major seed consumers [40].
Livestock also eat the seeds. High concentrations of resins and
terpenes render gray pine browse unpalatable [42].

More info for the terms: association, codominant, cover, density, forest, hardwood, natural, shrub, shrubs, tree, woodland

Gray pine and blue oak (Quercus douglasii) occur together over much of
California's oak woodlands. The blue oak-gray pine community varies in
stand density and composition, often sharing dominance with several
other tree species. The understory may be mostly grasses, shrubs, or
mixtures of both [16]. Pure stands of gray pine occur in localized
areas of serpentine soil [21], but more often, blue oak provides more
cover within the community type. At lower elevations, the blue oak-gray
pine woodland grades into chaparral, valley oak (Q. lobata) woodland, or
Oregon white oak (Q. garryana) woodland. At higher elevations, it mixes
with California black oak (Q. kelloggii) or ponderosa pine (Pinus
ponderosa) forest [16,26]. In its easternmost distribution, gray pine
merges with desert communities such as western juniper (Juniperus
occidentalis) and big sagebrush (Artemisia tridentata) near the Great
Basin and singleleaf pinyon (P. monophylla)-California juniper (J.
californica) near the Mojave Desert [16].

Plant associates: Overstory associates not mentioned in Habitat Types
and Plant Communities or SAF Cover Types include Coulter pine (P.
coulteri), California buckeye (Aesculus californica), interior live oak
(Quercus wislizenii), bigcone Douglas-fir (Pseudotsuga macrocarpa), and
MacNab cypress (Cupressus macnabiana) [3,11,18,26,43].

Common shrub associates include toyon (Heteromeles arbutifolia),
wedgeleaf ceanothus (Ceanothus cuneatus), chamise (Adenostoma
fasciculatum), California scrub oak (Q. dumosa), desert scrub oak (Q.
turbinella), California buckthorn (Rhamnus californicus), common
manzanita (Arctostaphylos manzanita), birchleaf mountain-mahogany
(Cercocarpus betuloides), poison-oak (Toxicodendron diversilobum),
Sargent cypress (Cupressus sargentii), and hollyleaf cherry (Prunus
ilicifolia) [2,3,11,24,26].

Common ground associates include slender oat (Avena barbata), California
buckwheat (Erigonum fasciculatum), soft chess (Bruomus hordeaceus),
ripgut brome (B. rigidus), cutleaf filaree (Erodium cicutarium), bur
clover (Medicago hispida), ground lupine (Lupinus bicolor), and tarweed
(Hemizonia spp.) [3,8,24].

Publications listing gray pine as a dominant or codominant species are
as follows:

A classification system for California's hardwood rangelands [2]
Blue oak communities in California [3]
Association types in the North Coast Ranges of California [12]
Natural terrestrial communities of California [26]

More info for the term: tree

Tree

More info for the terms: cone, tree

Gray pine is considered an undesirable weed tree by many rangeland
managers. Production and quality of forage growing under gray pine is
less than that growing under blue oak. Additionally, gray pine provides
little shade for livestock during hot summer months [13,22,40]. It has
been extensively cut within the last century in order to clear rangeland
areas [40].

Diseases: Prominent diseases of gray pine include western gall rust
(Periderium harknessii) and dwarf-mistletoe (Arceuthobium occidentale
and A. campylopodum forma campylopodum) [1,20,31,40]. Western gall rust
forms galls on gray pine throughout its range but rarely causes serious
damage. Dwarf-mistletoe is a particularly damaging and widespread
disease [40]. It infects trees of all ages, causing reduced tree vigor
or death. Left uncontrolled, infection can increase sixty-fold within
10 years [20]. Arceuthobium occidentale also infects Douglas-fir
(Pseudotsuga menziezii) and bigcone Douglas-fir, while A. campylopodum
forma campylopodum can infect Coulter, Jeffrey (Pinus jeffreyi),
Monterey (P. radiata), and ponderosa pines [20,31]. Dwarf-mistletoe is
controlled by cutting infected trees or removing infected branches [31].

Gray pine is the specific host for Ips spinifer. This bark beetle
generally attacks fire- or drought-weakened trees. Heavy resin
production by healthy trees provides a strong defense against most
species of bark beetles. Gray pine is host to a variety of cone, twig,
and foliage insects, but the damage they cause is usually minor [40].

Gray pine growing in hardpan is susceptible to windthrow under
waterlogged soil conditions [40].

The percent composition of gray pine seeds is as follows [47]:

protein 25.0
fat 49.4
carbohydrate 17.5
Kcal/100 g 571

The concentrations of several essential minerals in gray pine seeds
are available [47].

CA

Gray pine seeds were important in the diet of California Indians [40].

More info on this topic.

The seasonal development of gray pine is as follows:

growth starts: March to April [35]
pollination: March to April [15,40]
fertilization: Spring following pollination [40]
cones mature: September to October [40]
seeds dispersed: October to February [40]

More info for the terms: cover, density, severity, wildfire

Information regarding postfire recovery of gray pine is sparse. Keeley
[30] reported a gray pine seedling density of 133 per acre (54/ha)
following a wildfire of unreported severity at Bartlett Springs, Lake
County. Percentage cover provided by gray pine in a blue oak-gray pine
community often decreases when fires are frequent. Many blue oak
ecotypes sprout following fire, and under a regime of frequent fire,
rapidly growing blue oak sprouts interfere with gray pine seedling
growth [16,26].

More info for the terms: ground residual colonizer, root crown, secondary colonizer, seed

Tree without adventitious-bud root crown
Ground residual colonizer (on-site, initial community)
Secondary colonizer - on-site seed
Secondary colonizer - off-site seed

More info for the terms: ecotype, epigeal, seed, stratification

Gray pine produces seed at 10 to 25 years of age [33]. It is a
consistent seed producer, with large crop outputs at 2- to 3-year
intervals [40]. Gray pine has delayed seed dispersal [10,46]. Cones
open slowly, shedding seed over a period of several months [40]. Seeds
are disseminated by animals, gravity, and water [1,40]. Scrub jay and
acorn woodpecker are the most effective animal disseminators [40].

Seeds require cold stratification for approximately 30 days prior to
germination [27,33]. The exact stratification period varies with
ecotype. Seedbank-stored seed remains viable for up to 5 years [33].
Germination rates improve when the seed is scarified and increase
greatly when the nuclear cap is removed [40,48]. Germination is epigeal
[33]. Seedlings establish best on bare mineral soil under partial
shade. Most first-year growth occurs in the taproot. Subsequent top
growth is rapid; early growth rates of gray pine are among the most
rapid of all conifers. Rate of top growth averages 28 inches (70 cm)
per year for the first 8 years of life [40].

Gray pine does not reproduce vegetatively [40].

More info on this topic.

This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

3 Southern Pacific Border
4 Sierra Mountains
7 Lower Basin and Range

More info on this topic.

More info for the terms: climax, seed

Blue oak-gray pine communities are fire climax and are replaced by
ponderosa pine or other coniferous forests in the absence of fire
[16,26,32]. Gray pine readily establishes from seed on disturbed sites
and is common in all seral stages of the blue oak-gray pine community
[30]. Young trees tolerate partial shade [40]. Mature trees are shade
intolerant [25].

The scientific name for gray pine is Pinus sabiniana Dougl. [36,39].
There are no infrataxa [40].

More info for the terms: seed, tree, xeric

Gray pine has been planted on a limited basis for erosion control.
Commercial nursery stock is unavailable. Seedlings have been
established on rehabilitation sites by planting 1- or 2-year-old
bareroot stock grown from locally collected seed [27,29]. Gray pine
is an appropriate choice for planting in soils with calcium imbalances.
It will grow well on both serpentine soil, where calcium is deficient,
and on limestone soil, where calcium is abundant. In addition, it will
grow on xeric sites where establishment of other tree species is
difficult [40].

More info for the term: density

Gray pine wood has minor commercial value. It is used for making
railroad ties, box shook, pallet stock, and chips. Poor form, high
resin content, and high proportions of compression wood result in low
stumpage prices. The mechanical strength properties of the wood have
been detailed [49]. Gray pine is expensive to log due to low stand
density [40].