James L. Jenkinson
Jeffrey pine (Pinus jeffreyi) was discovered in 1852 in the Shasta Valley of California by John Jeffrey, a Scottish botanical explorer. Partly overlapping ponderosa pine (Pinus ponderosa) in range and superficially resembling it, Jeffrey pine was first classified as a variety of ponderosa pine (28,45). These western yellow pines produce wood of identical structure and quality and are closely related taxonomically (10). Jeffrey pine is distinct chemically, ecologically, and physiologically and is readily distinguished from ponderosa pine on the basis of bark, leader, needle, bud, and cone morphology (23).
General: The Jeffrey pine may live 400 to 500 years and can attain immense size. It typically grows to 4 to 6 feet in diameter, and 170 to 200 feet in height. To date, the largest Jeffrey pine recorded in the western Sierra Nevada had a diameter of 7.5 feet, and a height of 175 feet.
The Jeffrey pine needles are in bundles of three (3), and are 7 to 11 inches long. Its’ cones are 6 to 10 inches long, and oval lacking the spines, which make ponderosa pine cones prickly.
The Jeffrey pine bark is deeply furrowed, and reddish-brown compared to orange of the ponderosa pine. It also has a strong vanilla or pineapple odor.
Distribution: Jeffrey pine is found primarily in California extending north through the Klamath Mountains into southwestern Oregon, across the Sierra Nevada into western Nevada, and south to the Transverse and Peninsular Ranges and into northern Baja California. In the northeast, central, and southern portions of its range, climate and elevation determine its distribution, rather than soil type.
Habitat: The Jeffrey pine can occupy many sites from the edges of moist, high mountain meadows to arid slopes bordering deserts, and it will grow over a wide range of elevations. The Jeffrey pine also grows in a diverse range of climatic conditions. It grows well on harsh and infertile sites. It is tolerant of drought, adapts to cold weather because it requires a shorter growing season than the ponderosa pine. Cold winters largely determine its presence in the Klamath, western Sierra Nevada, and southern California ranges.
Regularity: Regularly occurring
Jeffrey pine thrives in comparatively harsh environments throughout most of its range (1,21,24,55,58). Contrasted with ponderosa pine, Jeffrey pine completes annual top growth sooner, enters dormancy earlier, and requires longer cold exposure for leader growth in spring (27). Because Jeffrey pine is especially cold hardy (21,22), tolerant of drought (51,58,59), and adapted to short growing seasons, it competes well and typically dominates other conifers on cold, xeric, and infertile sites.
- The native range of Jeffrey pine.
The Jeffrey pine grows on a wide variety of well-drained soils. In the northwest portion of its range, the Jeffrey pine grows on infertile soils. However, it typically grows on infertile soils, mostly shallow and fine, fine loamy, and clay-textured gravelly surface soils. This pine grows at elevations as low as 200 feet.
In the Sierra Nevada, Jeffrey pine typically grows on volcanic soils with coarse soil texture, as gravelly sandy loams or loamy coarse sands. Jeffrey pine grows at elevations from 1,600 to over 9,000 feet.
Jeffrey pine has exhibited potential for re-vegetation of acid mine waste sites in northeastern California. It was found to be well adapted to a sulfur mine spoil site that was high in acidity and low in nitrogen availability.
Aboveground description: Jeffrey pine is a large, slow-growing, long-lived conifer [63,133]. Trees often live 400 or 500 years. In Jeffrey pine/huckleberry oak vegetation in central Sierra Nevada, the oldest Jeffrey pine tree was an estimated 631 years old . Jeffrey pine may reach 200 feet (60 m) tall [69,112], and diameters of up to 8.2 feet (2.5 m) are reported . Crowns are rounded  or long and symmetrical .
|Tree maturity and site conditions affect form and size. Rounded crowns are typical for mature trees, and young trees often have pyramidal crowns. Lower branches are large and somewhat droopy, and upper branches are smaller and ascending . At high-elevation sites, Jeffrey pine can be deformed by high winds . |
The Jeffrey pine trunk is normally straight with thick, large plates of bark separated by deep furrows [32,54,130,198]. Jeffrey pine saplings and adults averaging 2 inches (5 cm) and 48.8 inches (124 cm) in diameter had estimated bark thicknesses of 0.2 inch (0.5 cm) and 2.6 inches (6.5 cm), respectively . Fifty Jeffrey pine trees from the south slope of Mt Pinos in southern California with an average DBH of 21 inches (53 cm) had an average bark thickness of 2.1 inches (5.3 cm) .
|Charles Webber Â© California Academy of Sciences|
Needles are 3 to 11 inches (8-28 cm) long and most often in bundles of 3, but bundles of 2 are possible [69,112]. Needles are retained for 2 to 10 years [32,69]. Needle thickness varies with location on the tree and elevation. Needles in the sun are thicker than those in the shade, and needles on trees at high-elevation sites are thicker than those on trees at low-elevation sites . Pollen cones are small, 0.8 to 1.4 inches (20-35 mm) long, and female cones are large, 4.7 to 12 inches (12-30 cm) long [69,112]. Cone size can vary between years and sites. The largest Jeffrey pine cones are produced in the Reno-Tahoe area, according to Haller . Female cones mature 2 summers after being pollinated . Jeffrey pine produces winged seeds. Seeds are between 10 and 13 mm long, and wings are up to 1.2 inches (3 cm) long [112,130]. Seed weight averages 123 mg (Forest Service, US Department of Agriculture, cited in ).
Belowground description: The Jeffrey pine taproot penetrates deeply, and lateral roots are considered "strong" and "extensive". In an open stand, on shallow ultramafic soils in the northern Sierra Nevada, Jeffrey pine roots up to 2 inches (5 cm) in diameter were found in a soil pit 100 feet (30 m) from the nearest tree .
Sierra Nevada Forests
The Limestone salamander is a highly localized endemic of the Sierra Nevada forests foothills conifned to a limited reach of the Merced River. The Sierra Nevada forests are the forested areas of the Sierra Nevada Mountains, which run northwest to southwest and are approximately 650 kilometers long and 80 km wide. The range achieves its greatest height towards the south, with a number of peaks reaching heights of over 4000 meters. Several large river valleys dissect the western slope with dramatic canyons. The eastern escarpment is much steeper than the western slope, in general.
The Sierra Nevada forests ecoregion harbors one of the most diverse temperate conifer forests on Earth displaying an extraordinary range of habitat types and supporting many unusual species. Fifty percent of California's estimated 7000 species of vascular plants occur in the Sierra Nevada, with 400 Sierra endemics and 200 rare species. The southern section has the highest concentration of species and rare and endemic species, but pockets of rare plants occur throughout the range.
Sierra Nevada amphibian endemics are the Yosemite toad, Mount Lyell salamander (Hydromantes platycephalus), the Vulnerable Limestone salamander (Hydromantes brunus), Kern salamander and the Endangered Inyo Mountains salamander (Batrachoseps campi). The non endemic amphibians are: the Endangered Southern mountain yellow-legged frog (Rana muscosa); the Near Threatened Cascades frog (Rana cascadae); Northern red-legged frog (Rana aurora); Pacific chorus frog (Pseudacris regilia); Foothill Yellow-legged frog (Rana boylii); Long-toed salamander (Ambystoma macrodactylum); and the Monterey ensatina (Ensatina eschscholtzii).
A considerable number of mammalian taxa are found in the ecoregion, including the Long-eared chipmunk, Alpine chipmunk, Western heather vole, Walker Pass pocket mouse, and the Yellow-eared pocket-mouse. A diverse vertebrate predator assemblage once occurred in the ecoregion including Grizzly bear (Ursus arctos), Black bear (Ursus americanus), Coyote (Canis latrans), Mountain lion (Puma concolor), Ringtail (Bassariscus astutus), Fisher (Martes pennanti), Pine marten (Martes americana) and Wolverine (Gulo gulo).
There are a small number of reptilian taxa present in the Sierra Nevada forests: sagebrush lizard (Sceloporus graciosus); Northern alligator lizard (Elgaria coerulea); Southern alligator lizard (Elgaria multicarinata); Sharp-tailed snake (Contia tenuis); California mountain kingsnake (Molothrus ater); Common garter snake (Thamnophis sirtalis); Couch's garter snake (Thamnophis couchii); Western gopher snake (Pituophis catenifer); Longnose snake (Rhinocheilus lecontei); and the Common kingsnake (Lampropeltis getula).
A number of bird species are found in the ecoreion including high level predators that include several large owls, hawks and eagles. Other representative avifauna species present are the Blue-headed vireo (Vireo solitarius); Brown-headed cowbird (Molothrus ater); and the Near Threatened Cassin's finch (Carpodacus cassinii).
Sierra Juarez and San Pedro Martir pine-oak forests Habitat
This taxon can be found in the Sierra Juarez and San Pedro Martir pine-oak forests. The ecoregion is located in two mountain ranges in the state of Baja California, Mexico: the Sierra de Juarez and the Sierra de San Pedro Martir. Both mountain ranges belong to the physiographical province of Baja California, and constitute the northernmost elevated peaks of the Baja Peninsula. The mountainous range that descends into a large portion of Baja California becomes more abrupt at Juarez and San Pedro Martir; the eastern slope is steeper than the western. Altitudes range between 1100-2800 meters. The granitic mountains of Juarez and San Pedro Martir have young rocky soils and are poorly developed, shallow, and low in organic matter.
Dominant trees in the ecoregion are: Pinus quadrifolia, P. jeffreyi, P. contorta, P. lambertiana, Abies concolor, and Libocedrus decurren. The herbaceous stratum is formed by Bromus sp. and Artemisia tridentata. Epiphytes and fungi are abundant throughout the forests.
Characteristic mammals of the ecoregion include: Ornate shrew (Sorex ornatus), Puma (Puma concolor), Fringed Myotis bat (Myotis thysanodes), California chipmunk (Tamias obscurus), Bobcat (Lynx rufus), Coyote (Canis latrans), San Joaquin kit fox (Vulpes macrotis) and Bighorn sheep (Ovis canadensis).
Numerous birds are present in the ecoregion, including the rare Bald eagle (Haliaeetus leucocephalus), California condor (Gymnogyps californianus), Pinyon jay (Gymnohinus cyanocephalus), and White-breasted nuthatch (Sitta carolinensis).
A number of different reptilian taxa are found in these oak-pine forests; representative reptiles here are: the Banded rock lizard (Petrosaurus mearnsi); Common checkered whiptail (Cnemidophorus tesselatus), who is found in sparsely vegetated areas; Coast horned lizard (Phrynosoma coronatum), often found in locales of sandy soil, where individuals may burrow to escape surface heat; Night desert lizard (Xantusia vigilis), who is often found among bases of yucca, agaves and cacti; and the Baja California spiny lizard (Sceloporus zosteromus).
The Pacific chorus frog (Pseudacris regilla) is an anuran found within the Sierra Juarez and San Pedro Martir pine-oak forests as one of its western North America ecoregions of occurrence. The only other amphibian in the ecoregion is the Western toad (Anaxyrus boreas).
California Montane Chaparral and Woodlands Habitat
This taxon can be found in the California montane chaparral and woodlands, a near coastal ecoregion in Central and Southern California, USA. This ecoregion is disjunctive, with a major element in Southern California and another along the Monterey County coast. The ecoregion encompasses most of the Transverse Range that includes the San Bernardino Mountains; San Gabriel Mountains; portions of the Santa Ynez and San Rafael Mountains; Topatopa Mountains; San Jacinto Mountains; the Tehachapi, Greenhorn, Piute, and Kiavah Mountains that extend roughly northeast-southwest from the southern Sierra Nevada; and the Santa Lucia Range that parallels the coast southward from Monterey Bay to Morro Bay.
The California montane chaparral and woodland ecoregion consists of a complex mosaic of coastal sage scrub, lower chaparral dominated by chamise, upper chaparral dominated by manzanita, desert chaparral, Piñon-juniper woodland, oak woodlands, closed-cone pine forests, yellow pine forests, sugar pine-white fir forests, lodgepole pine forests, and alpine habitats. The prevalence of drought-adapted scrub species in the flora of this ecoregion helps distinguish it from similar communities in the Sierras and other portions of northern California. Many of the shared Sierra Nevadan species typically are adapted to drier habitats in that ecoregion, Jeffrey Pine (Pinus jeffreyi) being a good example.
Oak species are an important component of many chaparral and forest communities throughout the ecoregion. Canyon Live Oak, Interior Live Oak, Tanbark Oak (not a true Quercus species), Engelmann Oak, Golden-cup Oak, and Scrub Oak are some examples. Mixed-conifer forests are found between 1371 to 2896 meters elevation with various combinations and dominance of incense cedar, sugar pine, and white fir, Jeffrey Pine, Ponderosa Pine, and mountain juniper. Subalpine forests consist of groves of Limber Pine (Pinus flexilis), Lodgepole Pine, and Jeffrey Pine. Very old individual trees are commonly observed in these relict subalpine forests. Within this zone are subalpine wet meadows, talus slope herbaceous communities, krumholz woodlands, and a few small aspen groves.
In addition to these general vegetation patterns, this ecoregion is noted for a variety of ecologic islands, communities with specialized conditions that are widely scattered and isolated and typically harbor endemic and relict species. Examples include two localities of Knobcone Pine (Pinus attenuata) on serpentine soils, scattered vernal pools with a number of endemic and relict species, and isolated populations of one of North America’s most diverse cypress floras, including the rare Gowen Cypress (Cupressus goveniana goveniana) restricted to two sites on acidic soils in the northern Santa Lucia Range, Monterey Cypress (Cupressus macrocarpa) found only at two coastal localities near Monterey Bay, and Sargent Cypress (Callitropsis sargentii LR/LC) restricted to serpentine outcrops. Monterey Pine (Pinus radiata) is also restricted to three coastal sites near Monterey Bay.
The ecoregion is also home to a few endemic or near-endemic mammalian vertebrates, such as the White-eared Pocket Mouse (Perognathus alticolus EN), a mammal known only to two disjunct mountain ranges in southern California: San Bernardino Mountains in San Bernardino County (ssp. alticolus), and the Tehachapi Mountains, in Kern, Ventura, and Los Angeles counties. The near-endemic fossorial Agile Kangaroo Rat (Dipodomys agilis) is found in the southern disjunctive unit of the ecoregion, and is known only to the Los Angeles Basin and foothills of San Gabriel and San Bernardino mountains in Ventura, Los Angeles, and Riverside counties north to Santa Barbara County and through the southern Sierra Nevada, including Mount Pinos, Tehachapi and San Gabriel mountains, and northern San Fernando Valley. Non-endemic mammals found in the ecoregion include Botta's Pocket Gopher (Thomomys bottae) and Trowbridge's Shrew (Sorex trowbridgii). Some larger vertebrate predators can be found in the ecoregion, including Puma (Puma concolor), Bobcat (Lynx rufus), Coyote (Canis latrans), and Ringtails (Bassariscus astutus).
The ecoregion boasts five endemic and near-endemic amphibians, largely Plethodontid salamanders. Some specific salamander taxa found here are the endemic Tehachapi Slender Salamander (Batrachoseps stebbinsi VU), known from isolated sites in the Caliente Creek drainage, Piute Mountains, and Kern County, California along with scattered populations in the Tehachapi Mountains to Fort Tejon, Kern County; the near-endemic Blackbelly Slender Salamander (Batrachoseps nigriventris); the Monterey Ensatina (Ensatina eschscholtzii); the Channel Islands Slender Salamander (Batrachoseps pacificus), endemic to a narrow range restricted solely on Anacapa, Santa Cruz, Santa Rosa, and San Miguel islands; and the Arboreal Salamander (Aneides lugubris), found only in California and Baja California. A newt found here is the Coast Range Newt (Taricha torosa). Anuran taxa in the ecoregion include the Foothill Yellow-legged Frog (Rana boylii NT); the Southern Mountain Yellow-legged Frog (Rana muscosa EN), a California endemic occurring in several disjunctive populations; and the Northern Red-legged Frog (Rana aurora).
The California montane chaparral and woodlands ecoregions contains a number of reptiles such as the Coast Horned Lizard (Phrynosoma coronatum), who ranges from Northern California to Baja California. Also found here is the Sagebrush Lizard (Sceloporus graciosus); the Western Fence Lizard (Sceloporus occidentalis); the Southern Alligator Lizard (Elgaria multicarinata); and the Side-blotched Lizard (Uta stansburiana). The Two-striped Garter Snake (Thamnophis hammondii) is a restricted range reptile found near-coastally from Monterey County, California southward to Baja California.
The California Condor once inhabited much of the ecoregion, with the western Transverse Range acting today as a refuge for some of the last wild populations, after considerable conservation efforts, especially in the Los Padres National Forest. The Heermann's Gull (Larus heermanni NT) is found in coastal areas of the ecoregion.
Habitat and Ecology
Comments: In México the species grows 1500-3000 m altitude along the rocky ridges, basins and arroyos of the Sierra de Juárez and San Pedro Mártir in Baja California Norte. Annual rainfall 300-500 mm.
Jeffrey pine occupies habitats from the edges of moist, high-elevation meadows to the borders of arid deserts , but is often dominant on dry, infertile sites throughout its range . Montane forests above the ponderosa pine zone are typical Jeffrey pine habitat .
Climate: Short growing seasons, drought, and cold are tolerated by Jeffrey pine . Throughout the Jeffrey pine range, average January temperatures range from 9 to 36 Â°F (-13 to 2 Â°C). Day and nighttime temperatures in July may differ by 47 Â°F (26 Â°C) in the Klamath Mountains and on eastern slopes of the Cascade Range and Sierra Nevada. Winter precipitation contributes most to the average annual precipitation in Jeffrey pine habitats. Annual precipitation levels are lowest on eastern slopes of the Cascade Range and Sierra Nevada and range from 15 to 17 inches (380-430 mm). Annual precipitation averages are much greater at elevations of 4,170 to 4,990 feet (1,270-1,520 m)) in the Klamath Mountains and on the western slopes of the Sierra Nevada. Average snow fall can be less than 30 inches (760 mm) on low-elevation sites in the Klamath Mountains and greater than 200 inches (520 cm) in high-elevation Sierra Nevada habitats .
Climate and growing conditions in Jeffrey pine habitats can vary considerably with elevation. In the Carson Range of western Nevada, annual precipitation levels based on 25 years of records averaged 23.3 inches (591.8 mm) at low, 29.3 inches (744.2 mm) at mid-, and 44 inches (1,118 mm) at high elevations. During a 2-year period, the average maximum temperature was about 16 Â°F (9 Â°C) higher at low- than high-elevation sites. Average daily maximum soil temperatures varied only about 5 Â°F (3 Â°C) between low- and high-elevation sites . For a short discussion of germination and seedling emergence at these sites, see Cached seed. In Jeffrey pine habitats in Baja California Norte, low-elevation sites averaged 12 to 20 inches (300-500 mm) of annual rainfall, and high-elevation sites averaged about 24 inches (600 mm). Snow was possible from December to February at high elevations. June through August were hottest and driest .
Cold tolerance: Jeffrey pine is considered more drought and cold tolerant than ponderosa pine based on site occupancy differences . However, Wagener  observed no mortality differences in young or old ponderosa pine and Jeffrey pine after extremely cold weather in California. In sympatric populations, mortality of ponderosa pine was less than Jeffrey pine. The researcher suggested that if cold tolerance differences exist between the species, they occur in the seedling stage or that cold causes damage other than mortality. For more on differences and similarities between Jeffrey pine and ponderosa pine, see Haller .
Jeffrey pine buds and leaves from 1-year-old twigs on 10- to 40-year-old trees collected in midwinter from California resisted injury at temperatures as low as -22 Â°F (-30 Â°C). Twig tissue resisted damage at -58 Â°F (-50 Â°C) .
|Jeffrey pine elevational range by state and region|
|California||1,500-10,600 [54,112] most common at 6,000-9,000 |
|Baja California Norte||1,500-9,500 [104,130,211]|
|North Coast and Klamath Ranges |
(on serpentine outcrops)
|as low as 200 |
|Slate Creek Valley of the Inyo National Forest||found trees at 10,000-11,000 |
|Sierra Nevada||5,000-9,000 |
|northern Sierra Nevada||4,990-6,000 |
|southern Sierra Nevada||6,990-8,990 |
|southern California||3,600-6,600 |
|San Bernardino Mountains||5,400-9,800 |
|Traverse and Peninsular ranges||4,500-9,800 |
Soils: Jeffrey pine typically grows on shallow, rocky, infertile soils  and survives on dry pumice and bare granite substrates . About 20% of Jeffrey pine's distribution occurs on ultramafic soils; the rest occurs on volcanic and granitic parent materials . In southwestern Oregon and northwestern California, Jeffrey pine is most typical of ultramafic soils, including serpentine [2,5,22]. Kruckeberg  considers Jeffrey pine a "faithful" indicator of serpentine soils at low to moderate elevations in northwestern California and southwestern Oregon. Kruckeberg also suggests that the main Jeffrey pine range is on nonserpentine soils, but that outlier populations are often restricted to serpentine soils .
The following paragraph provides more descriptive reports of the soils common in Jeffrey pine habitats throughout its range. Douglas-fir-Jeffrey pine forest types in the North Umpqua and Tiller Ranger Districts of southern Oregon occupy sites with shallow (x=15.7 inches (40 cm)), coarse-textured soils . On eastern slopes of the Sierra Nevada, Jeffrey pine is most common on decomposed granites . Jeffrey pine vegetation associations in upper montane habitats of central and southern Sierra Nevada occupy moderately deep to deep (x=32-39 inches (81-99 cm)) sandy to loamy soils with granitic or volcanic origins . The incense-cedar-Jeffrey pine cover type in Humboldt Redwoods State Park occurs on shallow serpentine soils . In Lassen Volcanic National Park, Jeffrey pine-white fir forests occurred on sites with higher pH (x=5.9) and greater basic cation (K, Ca, Mg) exchange capacity than other forest types . In the western Great Basin of Nevada, Jeffrey pine is restricted to soils derived from hydrothermally altered andesite. Altered soils have lower pH, calcium, and phosphorus than unaltered soils, which are dominated by big sagebrush. A lack of competing vegetation on these soils likely allows Jeffrey pine to tolerate the average annual precipitation of 262 mm/year, normally considered outside its tolerance range [26,27]. For a detailed description of soil composition and chemistry of Jeffrey pine stands in the Little Valley of Nevada, see Johnson . Soils in Jeffrey pine-mixed conifer forests in the Sierra San Pedro MÃ¡rtir are shallow, well to excessively drained, and strongly acidic (pH x=5.3). Organic matter averaged 2.3% in surface soils, and coarse-textured fragments averaged 26.5%. For more on soil nutrient composition, see Stephens and Gill .
Key Plant Community Associations
On very dry sites and on serpentine soils, Jeffrey pine is often a climax
species [2,129]. However on more productive sites and in mixed-conifer forests,
Jeffrey pine's dominance is dependent on recurrent fire. Without fire or other
disturbances that create gaps in the canopy, Jeffrey pine is often replaced by
more shade-tolerant conifers such as white fir (Abies concolor) [42,106].
The following lists are vegetation classifications in which Jeffrey pine is dominant.
General, western United States:
Jeffrey pine forests, cover type 247 of the Society of American Foresters 
Douglas-fir (Pseudotsuga menziesii)-Jeffrey pine forest type in the North Umpqua and Tiller Ranger Districts 
Jeffrey pine/huckleberry oak/red fescue (Quercus vaccinifolia/Festuca rubra) above 3,500 feet (1,100 m)
and Jeffrey pine/red fescue below 3,500 feet (1,100 m) in the upper Illinois River drainage of the Siskiyou Mountains 
General southwestern Oregon forest typings Â
Jeffrey pine/hoary manzanita/Idaho fescue (Arctostaphylos canescens/F. idahoensis)
Jeffrey pine/wedgeleaf ceanothus (Ceanothus cuneatus)/Idaho fescue
Jeffrey pine/Idaho fescue
Jeffrey pine/incense-cedar (Calocedrus decurrens)/huckleberry oak
Jeffrey pine/huckleberry oak-pinemat manzanita (A. nevadensis)
Jeffrey pine/huckleberry oak-pinemat manzanita-dwarf silktassel (Garrya buxifolia)
Jeffrey pine-incense-cedar/whiteleaf manzanita (A. viscida)
Jeffrey pine-incense-cedar-Douglas-fir 
incense-cedar-Jeffrey pine cover type in Humboldt Redwoods State Park 
The following eastside pine associations are recognized in northeastern California:
Jeffrey pine/mountain big sagebrush (Artemisia tridentata subsp. vaseyana)/Idaho fescue
Jeffrey pine/antelope bitterbrush-curlleaf mountain-mahogany/western needlegrass (Purshia tridentata-Cercocarpus
ledifolius/Achnatherum occidentale subsp. occidentale)
Jeffrey pine/antelope bitterbrush-Utah snowberry/bluegrass (Symphoricarpos oreophilus var.
Jeffrey pine/antelope bitterbrush/woolly mule-ears (Wyethia mollis)
Jeffrey pine/curlleaf mountain-mahogany
Jeffrey pine-California black oak/skunkbush sumac (Quercus kelloggii/Rhus trilobata
yellow pine (Jeffrey pine and ponderosa pine)/antelope bitterbrush/Idaho fescue/granite
yellow pine/curlleaf mountain-mahogany/arrowleaf balsamroot (Balsamorhiza sagittata)
yellow pine-California black oak/bluegrass on granite
Jeffrey pine-white fir/bluegrass on granite
Jeffrey pine-white fir/Utah snowberry/Wheeler bluegrass (P. nervosa)
yellow pine (Jeffrey pine and ponderosa pine)-white fir/western needlegrass on ash from recent pyroclastic flow
yellow pine (Jeffrey pine and ponderosa pine)-white fir/Utah snowberry/woolly mule-ears
yellow pine (Jeffrey pine and ponderosa pine)-white fir/pale serviceberry-Oregon-grape
(Amelanchier pallida-Berberis repens) 
Jeffrey pine phase of the white fir/tailcup lupine (Lupinus caudatus) habitat type on low southwest slopes
of the South Warner Mountains in Modoc County 
Jeffrey pine-white fir forests below 6,200 feet (1,900 m) in Lassen Volcanic National Park 
antelope bitterbrush/Jeffrey pine association on eastern slopes
in the Nevadense province (Lassen County and southward) 
Jeffrey pine upper montane forests at 4,990 to 6,000 feet
(1,520-1,830 m) in the northern Sierra Nevada and at higher elevations 6,990
to 8,990 feet (2,130-2,740 m) in the southern Sierra Nevada 
Jeffrey pine phase in midmontane coniferous and lower montane
eastside Sierran forests 
upper transition forest type in the Lake Tahoe region 
The following vegetation types are recognized in Yosemite National Park:
western juniper (Juniperus occidentalis)-Jeffrey pine woodlands on granitic domes above
6,600 feet (2,000 m)
California red fir-pine (Abies magnifica-Pinus spp.) forests 
Jeffrey pine forest in the Glass Mountain Region of east-central California 
The following old-growth mixed-conifer forest associations occur on the
Teakettle Experimental Forest:
Jeffrey pine/pinemat manzanita-greenleaf manzanita (Arctostaphylos patula)
Jeffrey pine/greenleaf manzanita-whitethorn ceanothus (Ceanothus cordulatus)
Jeffrey pine/greenleaf manzanita 
The following vegetation types occur in the upper montane region of central
and/or southern Sierra Nevada:
Jeffrey pine/huckleberry oak
Jeffrey pine/greenleaf manzanita-snowbush ceanothus (C. velutinus)
Jeffrey pine/whitethorn ceanothus-big sagebrush (Artemisia tridentata)
California red fir-white fir-Jeffrey pine
Jeffrey pine-California red fir 
Jeffrey pine and Jeffrey pine-white fir types of southern California forest formations 
yellow pine forests on dry transmontane slopes in southern California 
Jeffrey pine forests in lower montane coniferous forest zones of the Transverse and
Peninsular ranges 
The following vegetation associations are found in the San Bernardino Mountains:
pine forest type at elevations above 6,000 feet (1,800 m) 
mixed Jeffrey pine forests (may include white fir, sugar pine (P. lambertiana),
incense-cedar, and/or western juniper)
Jeffrey pine-canyon live oak (Q. chrysolepis)
Jeffrey pine/timber chaparral (whitethorn ceanothus and deer brush (C. integerrimus) common)
Jeffrey pine-birchleaf mountain-mahogany (Cercocarpus montanus var. glaber) 
western coniferous forest type, Jeffrey pine is most abundant on south slopes 
General California forest typings Â
Jeffrey pine forests throughout California on dry, cold, well-drained slopes, ridges, and basins
Jeffrey pine-fir (Abies spp.) forests on moister sites than Jeffrey pine
forest type listed above 
ponderosa pine-Jeffrey pine sparse vegetation community 
Soils and Topography
Above 1600 m (5,250 ft) in ultramafic regions and at all elevations everywhere else within its range, Jeffrey pine grows on any well-drained forest soil, regardless of parent material. Most of the usual soils that carry Jeffrey pine are coarse or gravelly sandy loams or loamy coarse sands that often merge with rocklands. Where these soils are of recent volcanic origin (ashes, pumice, or cinders) they are Dystric or Typic Xerorthents or Xeropsamments of the order Entisols. Jeffrey pine characteristically grows on granitic soils in the Sierra Nevada. These soils extend over complex systems of branching ridges, ravines, and canyons at elevations ranging from 1520 to 2740 m (5,000 to 9,000 ft), are usually found in a humid microthermal climate, and vary from about 0.6 to 1.4 m (2 to 5 ft) deep. They are Dystric and Typic Xerochrepts and Xerumbrepts of the order Inceptisols. Volcanic soils and mud flows commonly support Jeffrey pine in the northern Sierra Nevada and adjacent Cascade Range. They are extensive on gentle to steep slopes of dissected plateau-like areas at elevations up to 1830 m (6,000 ft), and most vary from 0.5 to 1 m (1.6 to 3.3 ft) deep (31). They are Ultic, Typic, and Dystric Haploxeralfs of the order Alfisols.
East of the Sierra Nevada crest from Lassen to Alpine Counties, CA, and along the Virginia Range of adjacent western Nevada, isolated patches of Jeffrey and ponderosa pines grow on more than 125 islands of altered andesite (3). These edaphically restricted stands range in elevation from 1310 to 2130 m (4,300 to 7,000 ft), and many are within the Pinyon-Juniper woodland (20).
Summer nights are warmer and differences in day-night temperatures are smaller for Jeffrey pine in the western Sierra Nevada and southern California than elsewhere in the range. July day-night differences in these regions are as little as 11° C (20° F), and rarely exceed 19° C (34° F). In the Klamath Mountains and east of the Sierra-Cascade crest, July day-night differences mostly exceed 19° C (34° F), approach 26° C (47° F) in some areas, and decrease to 13° C (24° F) only for stands at highest elevations.
Throughout the range, precipitation falls mostly during the winter season. Mean annual rainfall averages as little as 380 to 430 mm (15 to 17 in) in places east of the Sierra-Cascade crest, is only 200 mm. (8 in) for certain stands scattered along the eastern Sierra Nevada and Virginia Range of western Nevada (3), and exceeds 1270 to 1520 mm (50 to 60 in) in parts of the western Sierra Nevada and Klamath Mountains. Mean snowfall in Jeffrey pine localities typically ranges from 30 cm (12 in) or less at lowest elevations in the Klamath Mountains to well over 520 cm (204 in) at high elevations in the Sierra Nevada, particularly along the central crest.
Habitat & Distribution
The Jeffrey pine regenerates sexually through seed production over a two-year cycle. Trees flower in June and July of the first year, and cones mature in the summer of the second year. Most seeds are shed in September and October. Seeds typically fall only about 100 feet from the parent tree, although fall storms with high winds may carry seeds up to 1/2 mile away.
On the west side of the Sierra Nevada, seed crops are borne every 2 to 8 years. Trees may start to bear cones as early as eight years old, but typical seed bearers are 30+ years old and 60 to 180 feet tall. Seeds germinate quickly in the spring. However, regeneration of Jeffrey pine by seed or replanting may fail due to poor seedbeds, sparse seed crops, poor seed dissemination, seed predators, cutworms, and diseases.
Seedlings establish most successfully on bare mineral soil. A major cause of regeneration failure is competition for moisture from other vegetation. Heavy competition from brush, grasses, and sedges for soil water can be lethal to Jeffrey pine seedlings in the dry summer period, while shade from shrubs can slow growth of surviving seedlings.
Jeffrey pine can grow to impressive size on the best sites, however; by contrast, stand productivity is low for Jeffrey pine on infertile sites, sometimes growing sparse stands in which 300-year-old trees are less than 100 feet tall.
Associated Forest Cover
South of the Pit River in northeastern California and on the east side of the Cascade Range in southwestern Oregon and northern California, Jeffrey and ponderosa pines form extensive forests and usually intermingle in both closed and open, parklike stands. Jeffrey pine forests range widely from 1520 to 2130 m (5,000 to 7,000 ft) of elevation in the northern Sierra Nevada, and from 1830 to 2900 m (6,000 to 9,500 ft) in the central and southern Sierra Nevada. Ponderosa pine, sugar pine, white fir, incense-cedar, California red fir, western white pine, lodgepole pine, and western juniper (Juniperus occidentalis) all mix in locally, but few of them join Jeffrey pine on south slopes and granitic soils (9,44).
Jeffrey pine is the dominant yellow pine in forests east of the Sierra Nevada crest and in the Transverse and Peninsular Ranges into Baja California. In the Sierra San Pedro Martir, it ranges from 1830 to 3050 m (6,000 to 10,000 ft) and shares the southern limits of sugar pine, white fir, incense-cedar, and lodgepole pine (10,45,52).
Jeffrey pine forests constitute one of the more unusual forest cover types in western North America (14). Because Jeffrey pine has wide edaphic and elevational ranges in diverse physiographic regions, Jeffrey Pine (Society of American Foresters Type 247) is highly variable and adjoins or merges with many others: Red Fir (Type 207), White Fir (Type 211), Lodgepole Pine (Type 218), Pacific Douglas-Fir (Type 229), Port-Orford-Cedar (Type 231), Douglas-Fir-Tanoak-Pacific Madrone (Type 234), Interior Ponderosa Pine (Type 237), Western Juniper (Type 238), Pinyon-Juniper (Type 239), Sierra Nevada Mixed Conifer (Type 243), Pacific Ponderosa Pine-Douglas-Fir (Type 244), Knob-cone Pine (Type 248), Canyon Live Oak (Type 249), and California Mixed Subalpine (Type 256). Associated understory species are diverse, reflecting climatic influences (14, p. 123).
Diseases and Parasites
Human activity is often damaging in other ways. Highway de-icing salts (48), sewage effluents (2), and air pollutants such as ozone (39) all may severely injure or kill Jeffrey pine. Like other conifers, Jeffrey pine is susceptible to herbicide damage at certain seasons of the year and stages of growth (40). Spraying during the growing season may kill trees or distort growth of new shoots, although observations in plantations suggest that Jeffrey pine resists phenoxy herbicide damage.
Among the biotic agents attacking Jeffrey pine are two needle diseases, a limb canker, at least five different rusts, western dwarf mistletoe, three major root diseases, and various heart rots (2).
Elytroderma disease (Elytroderma deformans) has reached epidemic proportions in stands into which cold air drains and has reduced growth and killed trees for years after major outbreaks (46). Medusa needle blight (Davisomycella medusa) has markedly decreased growth of individual trees, especially on poor sites after drought. Cenangium limb canker (Cenangium ferruginosum) may severely attack young trees growing under poor conditions and usually kills suppressed or weakened branches.
Stalactiform rust (Peridermium stalactiforme) infects lower limbs and spreads upward in the crowns of young Jeffrey pine; infected trees are almost always near the alternate hosts, particularly Castilleja spp. Filamentosum rust (Peridermium filamentosum) kills the middle or upper crowns of scattered mature trees, can spread from pine to pine, and has displayed a potential for intense outbreaks. Sweetfern rust (Cronartium comptoniae) frequently kills young trees, and tarweed rust (Coleosporium madiae) may cause heavy defoliation in occasional wet years. Western gall rust (Peridermium harknessii) kills seedlings and large trees of Jeffrey pine by producing abundant, globose branch galls or large bole-deforming stem cankers. Although its major outbreaks are often decades apart, this rust is ubiquitous in California and potentially hazardous to young Jeffrey pine in moderately cool, humid environments (2).
The worst disease of Jeffrey pine is caused by western dwarf mistletoe (Arceuthobium campylopodum). Heavy infections cause witches' brooms, severely reduce growth, and eventually kill the tree. Young trees are highly susceptible to infection from surrounding infected overstory trees (37). Dwarf mistletoe has predisposed many stands to insect attack and has induced 60 to 80 percent of all Jeffrey pine mortality in years of severe drought (4).
Fungal diseases of the roots of Jeffrey pine include annosus (Heterobasidion annosum), armillaria (Armillaria mellea), and black stain (Verticicladiella wagnerii). Fungi that cause heart rots in Jeffrey pine include species of Lentinus, Fomes, and Polyporus. In southern California, red rot (Dichomitus squalens) attacks Jeffrey pine through broken tops, bole wounds, and large dead limbs (2).
Insects that damage Jeffrey pine are as numerous as the fungal diseases. Collectively attacking every part of the tree, they include twig and needle scales, various defoliators, borers, and tip moths, several bark beetles, and a host of cone and seed feeders (17).
The ponderosa pine twig scale (Matsucoccus bisetosus) feeds on branches and stems of trees of all ages and is the most destructive of the scales. Two of the more serious defoliators are the pine needle sheathminer (Zelleria haimbachi) and pandora moth (Coloradia pandora). Larvae of the sheathminer have destroyed more than 75 percent of the new needles in localized outbreaks in California. Larvae of the pandora moth are among the largest of any forest insect and consume whole needles in spring before bud break. Extensive outbreaks occur every 20 to 30 years, cause heavy defoliation for 2 to 4 years, and predispose the trees to attack by bark beetles and borers.
The western pineshoot borer (Eucosma sonomana) stunts the needles and retards height growth of young trees by as much as 30 percent annually. The ponderosa pine tip moth (Rhyacionia zozana) kills current shoots of saplings and young trees up to 2 m (6 ft) tall and may chronically retard growth for many years. The fir coneworm (Dioryctria abietivorella) kills the terminal buds of saplings and poles and frequently causes a permanent fork in the main stem. Larvae of the pine reproduction weevil (Cylindrocopturus eatoni) can destroy saplings and young trees where brush competition causes severe water stress.
The Jeffrey pine beetle (Dendroctonus jeffreyi) is the single worst enemy of Jeffrey pine (13). This bark beetle is prevalent throughout the range of its host, and has caused staggering losses of timber in mature stands. Several other insects that attack the main stem commonly precede or accompany Jeffrey pine beetle, notably the California flatheaded borer (Melanophila californica) and two pine engravers, the emarginate ips (Ips emarginatus) and Oregon pine engraver (I. pini, or I. oregonis). The red turpentine beetle (Dendroctonus valens) also attacks injured or weakened Jeffrey pine and induces fatal attacks by other bark beetles. Throughout California, lethal bark beetle activity is usually associated with dwarf mistletoe infestation or root rots, indicating that pathogens predispose the trees to insect attacks (4).
Insects often cause major losses of Jeffrey pine cones and seeds. The worst of these are the Jeffrey pine seedworm (Laspeyresia injectiva) and ponderosa pine seedworm (L. piperana), which eat seeds within the immature cone (17,26).
Deer, jack rabbits and snowshoe hares, pocket gophers, porcupines, and domestic livestock damage and kill young Jeffrey pine. Resident, mobile populations of these mammals make substantial losses likely in most areas. Pocket gophers consume whole seedlings, feed on the roots, stem, and crown of saplings, and often annihilate young plantations (11). Porcupines commonly eat the inner bark and cambium of saplings and poles and either kill them outright or cause a spiketop above the girdled stem.
Fire Management Considerations
Prescribed fire is often used in Jeffrey pine habitats. The following sections provide information on surface and aboveground fuel characteristics and potential prescribed or wildfire behavior in Jeffrey pine vegetation.
The timing and severity of prescription fires in Jeffrey pine habitats depend on management goals and site conditions. Increased fire severity typically increases seedling establishment but can kill adult trees. Stand density is closely related to fire severity. Dense forests will likely fuel more severe fires than open-canopy forests. Fire may also be used to manipulate species composition in Jeffrey pine habitats. Fir trees are less likely to survive fire than Jeffrey pine, and cover of small-diameter firs can be reduced by low-severity fires. Clearly defined management goals, an understanding of site and stand conditions, and a well-designed prescription fire will produce the best results in the fire management of Jeffrey pine.
Fuels: Characteristics of fuels typical of Jeffrey pine habitats including needles, cones, litter, duff, small- and large-diameter stems, and snags are described from a large portion of Jeffrey pine's range.
Needles and cones: Jeffrey pine needles dry rapidly, ignite easily, and support fire spread . A fuelbed (35Ã35 cm, <2 inches (5 cm) tall), created from Jeffrey pine needles collected near Lake Tahoe, Nevada, produced a maximum flame height of 34 inches (87 cm) after being dried to 1.5% to 2.7% moisture. Average flame time was 64.7 seconds, and burn time averaged 391.4 seconds. Average combustion was 90.1%, and average rate of weight loss was 35.3 μg/s. Mean flame height produced by the Jeffrey pine fuelbed was the highest of all 13 western conifer species tested. Flame time was lowest of all species tested, and percent combusted was second to ponderosa pine. Based on the reported values, surface fires could be supported by Jeffrey pine needle litter, and rapidly and nearly complete combustion of surface fuels would be likely . Findings were similar for other Jeffrey pine needle fuel beds tested . The maximum flame length produced after 10 Jeffrey pine cones with 2.3% fuel moisture collected from the Tahoe Basin were burned in a fire chamber was 31 inches (80 cm). Flame and smolder times averaged 262 seconds and 4,412 seconds, respectively. Cone burn time averaged 4,674 seconds, and combustion averaged 89%. Cones burned almost completely to white ash. Flame length, smoldering time, and burn time produced by burning Jeffrey pine cones were the longest of the 9 pine species tested .
Surface and aboveground fuels: Fuel bed characteristics were averaged in 4 Jeffrey pine stands from the central Sierra Nevada. Stands were monocultures of Jeffrey pine saplings (1-4 inch (2.5-10 cm) DBH), pole-size (4-24 inch (10-60 cm) DBH), mature (24-47 inch (60-120 cm) DBH), or old (>47 inch (120 cm) DBH) Jeffrey pines. Litter and duff depths averaged 0.4 inch (1.1 cm) and 2 inches (5.4 cm), respectively. Litter and duff weight averaged 8.965 kg/mÂ². Woody fuel weight averaged 0.025 kg/mÂ² for the 0- to 0.25-inch (0.64 cm) size class; 0.196 kg/mÂ² for 0.25- to 1-inch (0.64-2.54 cm) size class; and 0.073 kg/mÂ² for the 1- to 3-inch (2.54-7.62 cm) size class. There were no woody fuels in the over 3-inch (7.62 cm) size class .
Litter and duff fuel loads were much greater and 1,000-hour fuel loads much less in Jeffrey pine forests from the southern California Valentine Camp Natural Reserve than Jeffrey pine forests in the Sierra San Pedro MÃ¡rtir National Park. The 2 areas differed in fire management. Fires have not been excluded from the Sierra San Pedro MÃ¡rtir like they have in southern California. A summary of the fuel loadings and canopy cover differences in the 2 sites is given below [161,162]. For additional information on these sites and their differences in stand structure and fire management, see Fire-return intervals and Succession without fire.
|Average fuel loads (SE) of Jeffrey pine forests in the Valentine Camp Natural Reserve and Sierra San Pedro MÃ¡rtir National Forest|
|1-hour fuels||10-hour fuels||100-hour fuels||1,000-hour fuels||litter and duff layer||canopy closure|
%, measured with densiometer
|Sierra San Pedro MÃ¡rtir National Forest, Baja California Norte ||0.11 (0.03)||0.85 (0.16)||1.20 (0.27)||13.64 (3.84)||8.69 (no duff)||40.1|
|Valentine Camp Natural Reserve, southern California ||3.13 (1.05)||1.78 (1.22)||28.38 (7.48)||44.4 |
In Jeffrey pine-mixed conifer forests of the Sierra San Pedro MÃ¡rtir, almost 50% of plots had no coarse woody debris. Coarse woody debris was defined as wood on the forest floor, at least 3 feet (1 m) long, with a large-end diameter of at least 5.9 inches (15 cm). Average coarse woody debris load was 15.7 t/ha but ranged from 0 to 154.5 t/ha. Rotten coarse woody debris was more abundant than sound coarse woody debris. Large-end diameters ranged from 5.9 to 38 inches (15-96 cm), and most were less than 18 inches (45 cm). The very patchy coarse woody debris distribution may have been a chance occurrence or more likely was because debris was concentrated in unburned microsites protected from fire by topography or rocks . See Snags and decay ecology for addition information on snags in Jeffrey pine habitats.
Fire behavior affected by fuel load: In the Blacks Mountain Experimental Forest, wildfire effects were studied in thinned, thinned and prescribed burned, and untreated ponderosa pine forests where Jeffrey pine was common. Before the treatments and the wildfire, there had been few fires in the area more than several acres in size since the early 1900s. Some thinned stands were burned in prescribed fires before the Cone wildfire in late September. Wildfire severity and postfire mortality (>90%) were greatest in untreated stands. Severe surface fires with some torching were common in the thinned stands and produced 40% to 60% mortality. Low-severity surface fire occurred in thinned and burned stands, with little mortality unless trees were adjacent to untreated stands . Differences in early fall, late fall, early spring, and late spring prescribed understory fires in open, mixed Jeffrey pine, Douglas-fir, and incense-cedar forests on the Quincy Ranger District of the Plumas National Forest are described by Kauffman and Martin . Prefire and postfire characteristics are provided. Fuel conditions, weather, fire behavior (heat combustion, spread rate, and flame length), fuel consumption, and postfire changes in litter, bare ground, and duff are described.
Burned and unburned soils: Many studies provide information on burned and unburned soils in Jeffrey pine forests. Blank and others  evaluate effects of a severe wildfire in Jeffrey pine forests that produced white ash on the soil surface are evaluated in comparisons of burned and unburned soils in Nevada's Toiyabe National Forest. Burned and unburned soils in the Little Valley area of the eastern Sierra Nevada were compared 20 years after a stand-replacing fire in a 100-year-old Jeffrey pine forest by Johnson and others . In the Tahoe National Forest, forest floor nutrient contents and soil chemical properties were compared on prescribed burned, logged and slash burned, and unburned Jeffrey pine-dominated sites. See Murphy and others  for details. Soil nutrients and chemistry were described 2 months before and 1 year after the July Gondola wildfire in a mixed-conifer forest in the southeastern part of Nevada's Lake Tahoe Basin. For results of this study, see Murphy and others . On the Teakettle Experimental Forest, soil temperatures, moistures, and respiration rates were evaluated on undisturbed, burned, thinned, burned and thinned mixed-conifer stands 2 years after disturbances by Concilio and others and Ma and others [23,93]. After a severe crown fire in Jeffrey pine-oak (California black oak and canyon live oak) woodlands, Goforth and others  compared the physical and chemical properties of ash and soils on burned and unburned sites. Soils from burned Jeffrey pine-oak woodlands were also compared to soils from burned mixed-conifer forests where tree densities averaged 5 times that of the woodlands.Defensible space: Instructions for creating defensible space and for constructing a defensible house in wildfire prone mixed-conifer forests of the Incline Village/Crystal Bay area of Lake Tahoe are available from Smith and Adams . Although instructions were designed for Incline Village/Crystal Bay, many provided suggestions are applicable to other wildland urban interface areas.
Broad-scale Impacts of Plant Response to Fire
Throughout California, survival of Jeffrey pine decreased with increased fire
severity and fuel
loadings. Low-severity fires typically produced low Jeffrey pine mortality.
All 4 Jeffrey pine trees monitored after a severe fire in Cuyamaca
Rancho State Park, California, died within 1 year of the fire. The study area had not burned
for 95 years or more, and forests had more white fir and incense-cedar and
greater stem density than they did before fire exclusion . Just a single
Jeffrey pine tree died after an October prescribed fire on Spooner Summit in Lake Tahoe Basin.
Prefire and postfire fuel loadings were 5.1 and 4.9 tons/acre, respectively. Of
the 245 Jeffrey pine trees marked before the fire, 26 suffered complete crown scorch but 1
year after fire had green growth. However, researchers predicted some additional
postfire mortality from insect attacks and drought. Dendroctonus valens and
Ips pini together attacked 31% of burned Jeffrey pine trees, and 53% and
12% of Jeffrey pine trees were
attacked by D. valens and I. pini alone, respectively . Less than 3% of the total canopy was
killed in the Starr King Fire, which burned south of Yosemite Valley in mixed
Jeffrey pine, red fir, and western
juniper vegetation. The fire burned from 4 August to 3 October; fire intensity
was very low in the first 10 days. Between 29 August and 9 September,
fire size nearly doubled. Fireline intensity estimated
beneath Jeffrey pine ranged from 29.49 to 539.48 BTU/s/foot. Downed Jeffrey pine
logs and snags burned "intensely" .
Seed caches on burned sites:
Researchers found that chipmunks preferred to cache seeds in ash and that
seedlings from caches on burned sites survived longer than those on unburned
sites. In the laboratory, long-eared and yellow-pine chipmunks from the Carson Range in Washoe County, Nevada,
located 98% of artificial caches made in the sand but just 2.3% of caches made
in ash. When chipmunks were provided seed to cache themselves, the average
number of caches made in ash was significantly greater than
the number made in sand (P=0.02). Researchers suggested
seeds in sand were easier to locate by smell than seeds in ash, and ash caching may have
reduced stealing or pilfering
by others . Seeds from artificial caches on
pine-dominated burned sites near Lake Tahoe, Nevada, produced 14.8 times more
seedlings than those on unburned plots (P=0.002). The rate of seed
removed by animals on burned sites was lower than on unburned sites for 1 to 5
months after fire. Caches in soil produced 3.5 to 8.5 times as many seedlings as
caches made in pine needle litter on the soil surface .
Postfire seedling establishment:
Often Jeffrey pine seedling abundance is greater on burned than unburned sites. Fire
severity and/or season can affect Jeffrey pine seedling establishment ,
and seedling recruitment on burned sites can continue for
many years after fire . Not all studies reported Jeffrey pine increases following fire [71,95,119],
and successful seedling establishment on burned sites may be gradual. Likely
postfire growing conditions, fire severity, and seed source availability affect the rate and success of
Jeffrey pine seedling establishment.
Jeffrey pine seedling densities were greater 2 years after than before spring
prescribed fires but reduced from prefire densities 2 years after fall
prescribed fires in mixed-conifer forests on the Quincy Ranger District of the Plumas
National Forest. Spring fires produced greater fireline intensities than did
fall fires, suggesting that increased fireline intensity produced better sites
for seedling establishment. However, Jeffrey pine seedling density also
increased between the prefire and second postfire sampling seasons on unburned
plots. Likely differences in fire intensity and spring and fall growing conditions affected
seedling establishment . For more information on this study, consult the Research Project Summary
Plant response to prescribed burning with varying season, weather, and fuel moisture in mixed-conifer forests of California.
The number of Jeffrey pine seedlings on 5-year-old burned sites was substantially greater
than on unburned mixed-conifer sites in northern California. The 1960 Donner Ridge
Fire was an escaped slash pile fire that burned in mid-August. Fire severity was
not described. In 1965, there were 496 Jeffrey pine seedlings (<0.8 inch (2 cm) DBH) on the 20-acre
(8 ha) burned site and just 1 on the unburned site .
Burned and unburned sites compared 7 and 14 years after this fire showed a much higher
density of Jeffrey pine seedlings and saplings on the burned than on the
unburned site. Mature trees were much more abundant on unburned than burned
sites, suggesting that the fire was severe enough to produce mortality in
Jeffrey pine trees .
|Density of mature, immature, and seedling |
Jeffrey pine on
7- and 14-year old burned and unburned plots (each 20 acres) 
|Mature (>20 cm DBH)||0.5||0.6||10.1|
|Immature (>5 years old and <20 cm DBH)||5.4||36.6||38.1|
|Seedling (≤5 years)||28.6||3.3||0.1|
Jeffrey pine recruitment was associated with moisture availability but not
recent fire in
old-growth, mixed-conifer stands on the Teakettle Experimental Forest. Jeffrey
pine recruitment was associated with wetter years (Palmer Drought Severity Index was
2.36). Just 17% of Jeffrey pine recruitment occurred 1 to 4 years after fire. Almost all
Jeffrey pine established
before 1865 in wet years during or shortly before an El NiÃ±o year. Researchers
suggested that low-severity fires on the dry, shallow soils occupied by
Jeffrey pine may not have produced favorable seedbed conditions .
Fire severity effects:
In the studies summarized below, postfire
Jeffrey pine recruitment was most abundant on sites burned in stand-replacing
fires; however, the sites burned in stand-replacing fires were evaluated 10 and
19 years after fire. Sites burned in "light intensity" fires did not have
abundant Jeffrey pine recruitment 2 years after fire. A lack of
multiple postfire studies with similar postfire sampling dates makes assessing
recruitment and mortality differences between fire severities and seasons difficult.
Density of Jeffrey pine seedlings (<2 inch (5 cm) DBH)) and saplings
(2-8 inch (5-20 cm DBH)) was typically much lower on burned than
unburned sites 2 years after "light intensity" prescribed fires in Cuyamaca Rancho State Park.
Mature Jeffrey pine mortality was limited. Fires occurred in
mixed-conifer-Jeffrey pine-California black oak woodlands with
chaparral-dominated understories. The Paso Picacho site burned in April, and the
Granite Springs and Oakzanita sites burned in December. On the Paso
Picacho site, the density of large Jeffrey pine trees on burned sites was more
than 3 times that of unburned plots. Jeffrey pine saplings were absent from
burned plots, and the seedling density on burned plots was nearly half that of
unburned plots. On the Granite Springs site, there were more large Jeffrey pine
trees on burned than unburned plots. It is unlikely, however, that large trees
were produced on burned sites, and likely differences between burned and
unburned sites existed before the fires. Sapling and seedling densities on
burned plots were significantly lower than on
unburned plots (P<0.01 and P<0.02, respectively). On the Oakzanita site, Jeffrey pine tree,
sapling, and seedling densities were greater on unburned than burned sites
. For additional information on this study, see the Research Project Summary
Response of vegetation to prescribed burning in a Jeffrey pine-California black
oak woodland and a deergrass meadow at Cuyamaca State Park, California.
A fall prescribed fire in the Tharp Creek Watershed of Sequoia National Park
produced 16.7% and 21.7% average annual Jeffrey pine mortality on 2 white fir-mixed conifer
sites monitored for 5 years after fire. Mortality was concentrated in the
subcanopy. The fire burned from 23 to 26 October 1990. Relative humidity during the day was 21% to 30% and at night was 30%
to 40%. Fuel moisture levels in the litter and duff averaged 28%. For 100-hour
and 1,000-hour fuels, moisture levels were 14% and 64%, respectively. At the
time of ignition, air temperatures were 50 to 61 Â°F (10-16 Â°C) and winds were calm. The fire was a combination of backing and strip head fires with flame lengths of 0.16 to 7.9 feet (0.05-2.4 m). One-hour,
10-hour, and 100-hour fuels were reduced by 96%, 77%, and 60%, respectively.
Tree (≥4.6 feet (1.4 m)) mortality was evaluated before and after fire as
well as from an unburned reference site. On unburned sites, there was no Jeffrey pine mortality.
Between 1 and 5 years after the fire, most tagged Jeffrey pine in the
subcanopy (below main canopy) and nearly half in the codominant canopy (part of main
overstory canopy) were dead. None of the tagged Jeffrey pine trees in the dominant canopy
(above codominant canopy) was killed. Researchers indicated that drought
conditions 3 years before and 2 years after the fire may have contributed to
mortality in the larger size classes. Basal area changes were also monitored before and after the fire.
Compared to the unburned control site, Jeffrey pine basal area increased
by an average of 0.27% and 0.42% on the 2 burned sites before the fire. From
1989 to 1994 (includes 1 year of prefire data), Jeffrey pine basal area was reduced by 6.5% and 10% on the
2 burned sites compared to the unburned site . For more information, see the entire Research Paper by Mutch and Parsons .
The relative densities of Jeffrey pine saplings and seedlings were much
greater and mature tree relative densities much lower on sites burned 10 to 19
years ago than on sites burned between 60 and 100 years ago in stand-replacing
fires. Burned areas were upper montane white fir-Jeffrey pine-mixed-conifer
forests in the Lake Tahoe Basin. In aerial photos of the Angora Ridge dated to
1917 and 1940, shrubs dominated. A forest canopy was developing in 1976,
although there were still shrub-dominated patches. Domestic sheep grazing in the
area may have affected vegetation recovery on Angora Ridge that burned 100 years
before this study .
|Relative density of Jeffrey pine trees, |
saplings, and seedlings on sites burned in stand-replacing fires between 10
and 100 years ago 
|Angora Ridge||Cathedral Creek||Cascade Lake||Luther|
|Approximate time since fire (years)||100||60||19||10|
|Saplings (<61 cm tall)||4.7||16||91||14|
|Seedlings (<10 cm in diameter)||0||1||100||17|
Mortality of Jeffrey pine trees may continue for several years on burned sites, and often
postfire insect attacks further weaken damaged trees causing additional
delayed Jeffrey pine mortality. After a small June prescribed fire in ponderosa
pine-Jeffrey pine forests in Lassen Volcanic National Park, all 14
ponderosa and Jeffrey pine trees (>18 inches (46 cm) in
diameter)) died. The first tree died 2 years after the fire, while most others died
3 years after the fire. Fire burned on a relatively steep slope. Other plots burned in
September did not kill all Jeffrey pine trees. Potential causes of delayed
mortality were not discussed . On the north shore of Lake Tahoe, the presence of bark beetles on
Jeffrey pine was compared on sites burned in prescription fires and unburned mixed-conifer forest plots. The fire produced
variable effects on individual trees. Of 389 Jeffrey pine trees evaluated,
crown scorch averaged 33%, and bole char height averaged 2.6 feet (0.79 m). A year after
the fire, bark beetle attacks were more numerous on burned than unburned Jeffrey
pine trees. Burned Jeffrey pine trees had a 24.8 times greater chance of bark beetle attack. Crown
scorch and bole char
height both had positive relationships (P=0.0001) with bark beetle
attack probability. Small trees were preferred by red
turpentine and Ips beetles but were not consistently chosen by Jeffrey pine beetles .
After a small lightning-ignited fire in a
mixed pine forest in Shasta County, California, adult Arhopalus asperatus
were observed on the most severely scorched
Jeffrey pine trees. Jeffrey pine trunks were
scorched up to 20 feet (6 m). Insect activity decreased
with time since fire .
Plant Response to Fire
Scorched Jeffrey pine on burned sites may regrow needles if terminal buds are not killed, and seedling establishment from surviving adult trees, adjacent unburned sites, and/or seed caching animals is likely on burned sites.
Terminal bud regrowth: Severely scorched trees sometimes produce new green growth from surviving terminal buds protected by scales [121,199,201]. On burned sites in the Sierra Nevada, half of 44 trees with 100% crown scorch and incinerated foliage on less than 50% of the tree produced new foliage in the first postfire year .
Seedling establishment: Jeffrey pine seedling establishment is improved in canopy gaps created by fire, where mineral soil is exposed and light levels are high . Survival of seed in fallen cones is not reported on burned sites. Jeffrey pine seeds in a test tube were killed after exposure to 210 Â°F (100 Â°C) temperatures for 0.5 hour . Seedlings on burned sites come from seed from surviving or nearby unburned mature Jeffrey pine trees , fire-scorched trees [199,201], and/or seed-caching animals [16,17]. Wagener [199,201] reported that "exceedingly good stands of seedlings" came from fire-scorched trees on burned sites in California. Additional information on Jeffrey pine seed dispersal and seedling establishment on burned sites is presented below.
Broad-scale Impacts of Fire
Jeffrey pine survival can be affected by tree size and fire timing. Survival likelihood is increased if Jeffrey pine is burned while dormant; trees are more vulnerable when actively growing [199,201]. Jeffrey pine is considered fire resistant as a 2- to 4-inch (5-10 cm) DBH sapling and highly resistant as an adult .
Wagener [199,201] observed Jeffrey pine trees on 29 burned sites in California and reported on burned tree and postfire characteristics that affected survival. Survival was more likely when trees were "young", "vigorous", and occupied "good" sites. Trees with heavy cone crops were sometimes more susceptible to mortality than equally damaged trees without cone crops. Trees with extensive crown scorch did not necessarily sustain severe bud damage, and often postfire crown growth 1 year after fire was much greater than 1 month following fire. Wagener noted that in most cases, more than 50% bud survival was necessary for tree survival. Live crown percentages were useful in predicting survival of fire-scorched Jeffrey pine, and postfire weather and insect conditions also affected survival [199,201]. The table below summarizes the levels of cambium, crown, and foliage injury that Jeffrey pine can sustain and yet likely survive.
|Percentage of cambium, crown, and foliage injury that "vigorous" Jeffrey pine trees on "above-average" sites burned by late-season (after 1 August) fires can sustain and still be expected to survive |
|Modifications to tree "vigor", site quality, and fire season||Cambium injury|| |
|Increased cambium injury||moderate (cambium kill <25% of circumference not >stump height, may be some narrow strip kill)||≥50||≥20|
|Below-average site condition||none-light||≥50||≥15|
|Midseason fire||none-light||≥50||15-25 or more|
|Low prefire "vigor", small crowns||none-light||≥60||≥15|
|Â¹Proportion of original crown in which twigs and buds are still alive after fire (includes parts bearing green or partially green foliage). |
Â²Proportion of green or partially green needles present regardless of crown location.
Immediate Effect of Fire
Adult Jeffrey pine often survives low-severity surface fires. However, mature Jeffrey pine mortality has been observed after prescribed fire in areas with accumulated litter or duff and/or woody ladder fuels . Severe surface and crown fires can kill Jeffrey pine.
POSTFIRE REGENERATION STRATEGY :
Tree without adventitious buds and without a sprouting root crown
Crown residual colonizer (on site, initial community)
Initial off-site colonizer (off site, initial community)
Fire adaptations: Jeffrey pine resists fire kill through a variety of structural and physiological adaptations. Rapid taproot growth and early development of insulating bark offer protection to Jeffrey pine seedlings and young trees . Jeffrey pine is considered moderately fire resistant as a sapling (2-4 inch (5-10 cm) DBH) and highly resistant as an adult . Thick bark, protected terminal buds, self-pruning branches, open crowns, and high moisture content of needles minimize Jeffrey pine fire damage . There is some speculation that deep bark fissures may be a fire adaptation . Jeffrey pine's ability to shed burning bark scales as a means to reduce fire damage has received mention in the literature , and firefighters have reported observing fires extinguished by shedding bark scales . Bark shedding processes have not been tested experimentally .
Bark thickness: Jeffrey pine bark is often described as thick; however, bark thickness measurements are rarely reported. Using regression analyses, bark thickness of saplings with a 2-inch (5 cm) DBH was estimated at 0.18 inch (0.46 cm). Jeffrey pine adults with a 48.8-inch (124 cm) DBH had an estimated bark thickness of 2.6 inches (6.5 cm) . From 50 Jeffrey pine trees with an average DBH of 21 inches (53 cm) on Mt Pinos in southern California, bark thickness averaged 2.1 inches (5.3 cm) [197,198].
Terminal bud survival: Terminal buds that survive fire can produce new needles in the first postfire year. On several burned sites in the Sierra Nevada, researchers monitored 44 trees that had complete crown scorch and foliage consumed on more than 50% of the tree height. Half of these trees produced new needles in the first postfire year .
Seedling establishment: Jeffrey pine seedling establishment is improved in canopy gaps created by fire, where mineral soil is exposed and light levels are high . Seedlings on burned sites come from seed from surviving or nearby unburned mature Jeffrey pine trees , fire-scorched trees [199,201], and/or seed-caching animals [16,17]. Wagener [199,201] reported that "exceedingly good stands of seedlings" came from fire-scorched trees on burned sites in California.
FIRE REGIMES: Jeffrey pine occurs in many habitats and with a variety of other species throughout its range. While low-severity surface fires are common in open-canopy forests with limited understory fuels, increased forest densities and an increased presence of ladder fuels in the understory fuel higher-severity fires. On a landscape scale, a mixed-severity fire regime occurs in Jeffery pine habitats.
Fuels: Fuel types and arrangements as they relate to fire behavior in Jeffrey pine forest types have been described in many areas. Both small and large fires are possible, but low- to moderate-severity surface fires were historically common in Jeffrey pine vegetation. However, in many areas fire exclusion has increased fuel loads and produced ladder fuels that may support larger, more severe fires than was common under historic FIRE REGIMES. Western dry pine and mixed-conifer forests were "shaped by stand-maintenance fire". Before around 1850, low-severity, frequent surface fires fueled by grasses, shrubs, small trees, needles, and fallen braches rarely killed thick-barked species like Jeffrey pine. Even in times of increased temperatures and decreased moisture, fires could be large but were not necessarily severe .
In open old-growth Jeffrey pine stands in the Lassen Fire Management Area, fuels were primarily loose needles, grasses, cones, scattered fallen branches, and bark pieces. Fuel accumulations were often heavier in dwarf mistletoe-infested areas because of fallen witches' broom and dead trees . On the southern slope of Mt Pinos, widely spaced Jeffrey pine and a discontinuous understory fueled small fires that produced a mosaic of small, even-aged tree groups. Lightning-ignited fires on Mt Pinos averaged less than 4 acres (2 ha) in size. Researchers noted that fire exclusion has led to increased densities of "spindly, sapling-size Jeffrey pine" [197,198]. The Jeffrey pine/curlleaf mountain-mahogany vegetation type on top of rocky volcanic substrates in northeastern California was "nearly fire proof" due to landscape position and a lack of fuels . For more specific details regarding fuels, fuel types, and fuel loadings, see Fire Management Considerations.
Ignitions: Lightning is a common ignition source in many Jeffrey pine forests, and southern California sheepherders referred to Jeffrey pines as "lightning trees". Seventeen years of modern lightning records in north-central Baja California suggest that anthropogenic ignitions were likely before 1950. The large number of spring fires and low levels of spring lightning suggested that lightning was not likely the sole ignition source .
On Mt Pinos, pine forests may experience 600 lightning strikes/summer, and single storms have produced over 100 lightning strikes. Lightning strikes can create "sleeper" trees that burn internally until the fire is extinguished, creeps out into dry fuels, or the tree ignites. Wiggins (personal communication in ) reported that sheepherders working in southern California advised against camping under Jeffrey pines or "lightning trees", and later that day a Jeffrey pine tree in his camp was struck by lightning . From a random sample of 277 Jeffrey pine trees on the upper southern slope of Mt Pinos, 32.5% had lightning damage .
In Lassen Volcanic National Park there were 302 lightning-ignited fires in the summers from 1931 to 1981. There were an average of 7 lightning fires/year. Occasionally, a single dry lightning storm started 6 or 7 fires. Most fires were small (<0.25 acres (0.1 ha)), but larger fires (≥300 acres (120 ha)) occurred at 8- to 10-year intervals . Between 1913 and 1989, there were more than 5,000 lightning ignitions recorded in the Modoc National Forest (Cavasso, personal communication in ). For an in-depth discussion on lightning: types of lightning strikes that are most likely to cause ignition, typical delay of fire activity following lightning strikes, most commonly struck features within western forests, tree damage or mortality from lightning strikes, and indirect mortality from forest pests attracted to lightning-damaged trees, see Taylor .
Fire severity: Low-severity fires are described in most qualitative Jeffrey pine fire literature, but Jeffrey pine forests have experienced fire severities ranging from low-severity surface fires to severe, stand-replacing surface and crown fires. In the northern Sierra Nevada, stand-replacing fires occurred even before the practice of fire exclusion, but crown fires were less common than moderate- and low-severity fires . The 2002 Biscuit Fire in southwestern Oregon burned 14.4% of Jeffrey pine forests in the area: 5.3% burned severely, 7.6% burned at moderate severity, and 1.5% burned with low severity. Low-severity fires lightly scorched the vegetation, killed only a few large trees that were present on the burned site, and consumed very small diameter fuels. Moderate-severity fires killed 40% to 80% of trees, consumed most litter and fine ground fuels. High-severity fires killed nearly 100% of trees .
The McNally Fire burned about 97,214 acres (39,341 ha) of Jeffrey pine forests in the Sequoia National Forest in the summer of 2002. About 6% of the area was unburned, 24.5% burned at low severity, 49% was moderately burned, and 21.6% burned severely. Unburned patches had less than 10% canopy cover change. On low-severity burned sites, crown scorch affected less than 40% of the canopy, and mortality occurred in seedling and sapling size classes. Moderately burned sites had 40% to 89% canopy crown scorch, but most overstory trees survived. Severely burned sites had more than 89% canopy scorch, and understory mortality was complete. The Manter Fire in the southern Sierra Nevada burned approximately 13,610 acres (5,508 ha) of Jeffrey pine forest in the summer of 2000. Low-severity, moderate-severity, and high-severity fires burned 24.5%, 43.6%, and 31.9% of the Jeffrey pine forests, respectively. The northern Sierra Nevada Storrie Fire burned 41.7% of a 316-acre (128 ha) Jeffrey pine forest at low severity in the summer of 2000. Moderate- and high-severity fires burned 52.8% and 5.6% of Jeffrey pine forests, respectively. All burned sites had not burned for an extended period, as long as 125 to 150 years on some sites .
The majority of Jeffrey pine and mixed Jeffrey pine forests burned at low severity in 1989 summer fires in the Sierra San Pedro MÃ¡rtir of Baja California Norte; however, stand-replacing fires occurred as well. Whether stand-replacing fires were a result of crown fire, severe surface fire, or a combination was not determined from the aerial photographs and vegetation maps used to assess fire damage. In the northern portion of the study area, the total area burned in Jeffrey pine forests was 770.7 acres (311.9 ha): 39% burned in low-severity surface fires, 26.8% in high-severity surface fires, and 34.2% in stand-replacing fires. Stand-replacing fires occurred primarily in areas surrounded by chaparral vegetation and at elevations below 5,200 feet (1,600 m). In northern mixed Jeffrey pine forests, 861.4 acres (348.6 ha) burned, 51.3% in low-severity surface fires, 27.9% in high-severity surface fires, and 20.8% in stand-replacing fires. In southern Jeffrey pine forests, 1,800 acres (729 ha) burned, 70.2% in low-severity surface fires, 23.1% in high-severity surface fires, and 6.7% in stand-replacing fires. Fire severity ratings were based on percentage of canopy cover remaining after fire: low-severity surface fires produced <10% canopy mortality, high-severity surface fires produced over 10% canopy mortality, and stand-replacing fires killed more than 90% of the canopy .
Fire-return intervals: Once scarred by a fire, Jeffrey pine trees easily develop scars from subsequent fires, making them excellent fire recorders and extremely valuable in fire history studies . Fire history studies from Jeffrey pine habitats span the entire range of the species. Most of these studies are summarized in the table below. Average fire-return intervals were typically lower in ponderosa pine- or Jeffrey pine-dominated forest types than in mixed-conifer- or white fir-dominated forest types. In a review of fire history studies in Jeffrey pine forests, Skinner and Chang  found fire-return intervals were more variable in upper montane than in low-elevation, pine-dominated forests, and that fire-return intervals in Jeffrey pine forests were more variable than those in ponderosa pine forests, although site conditions and fire frequency were similar. Reviewers suggested that fire frequency variability in Jeffrey pine forests may have been due to a limited fire season, slow fuel accumulations, and occupation of landscapes broken up by rocky outcrops .
|Historic and contemporary fire-return intervals in Jeffrey pine habitats by study area. Superscripts indicate data collected and used in analyses: see legend below.|
|Vegetation type||Time period (approximate)||Fire-return interval(s) (FRI); calculation method, if provided||Notes|
|Klamath Province, southwestern Oregon2 |
|Jeffrey pine/huckleberry oak-pinemat manzanita||1840-1950||x=7.3 years||fire frequency decreased after 1950 with fire exclusion |
|Jeffrey pine/huckleberry oak-pinemat manzanita-dwarf silktassel||1529-1950||x=24.8 years|
|Jeffrey pine-incense-cedar/huckleberry oak||1422-1950||x=10.6 years|
|Jeffrey pine-incense-cedar/whiteleaf manzanita||1620-1950||x=11.2 years|
|Upper montane and subalpine basins in Scott Mountains of Klamath Range1 |
|mixed conifer||1376-1941||x=54.5 years, range=5.8-276 years||no fires from 1950 to 1995 in any basin; fires frequent, mostly small sized, likely low to moderate severity |
|Southern Cascades, northeastern California1,3 [117,118]|
|open ponderosa pine-Jeffrey pine||1700-1849||7-49 years for widespread fires (≥7 units in 700 kmÂ² study area); 2-22 years for moderate-sized fires (≥4 units); a fire ≥1 unit in 93 of 150 years||conditions wetter/cooler than average 3 years before most widespread fires (P<0.05); most widespread fires in El NiÃ±o years; conditions wetter/cooler than average (P<0.05) before nonfire years ; fire frequency significantly (P<0.001) lower from 1906-1996 than 1750-1905; 1 fire after 1910 |
|Prospect Peak in Lassen Volcanic National Park1,3(2,630-ha study area) |
|Jeffrey pine (1,855 to 2,100 m)||1656-1849a||x=4.9 years (composite)||66.9% of fires in dormant season; fire size from 1627-1904: x=241 ha, range=39-742 ha; x FRI significantly different (P<0.05) between 1656-1904 and 1905-1994; x FRI on east < south < west slopes|
|Jeffrey pine-white fir (1,840-2,220 m)||1656-1849||x=7.5 years||82.5% of fires in dormant season; fire size from 1627-1904 x=195 ha, range 6-666 ha; x FRI on east < south < west slopes ; comparisons of presettlement and contemporary forests available in Succession without fire|
|Prospect Peak, Lassen Volcanic National Park1,2,3 [173,174]|
|Jeffrey pine||pre-1900||x=16 years, range=9.5-32 years||30% of fires in growing season; x FRI on east < west ≈ south slopes|
|white fir-Jeffrey pine||x=29.8 years, range=15.5-38 years||x FRI on east <west ≈ south slopes|
|Caribou Wilderness at southern tip of Cascade Range1,2,3(950-ha study area)|
|white fir-Jeffrey pine (density and basal area of white and red fir >Jeffrey pine) (2,060-2,360 m)||1735-1874||x=70 years (point)||29% low- (>75 stems/ha remaining), 46% moderate- (25-75 stems/ha), 25% high- (<24 stems/ha) severity fires|
|Thousand Lakes WildernessÂ¹,Â²,Â³|
|white fir-Jeffrey pine||pre-1900||x=14 years, range=7-25 years||4% low-, 44% moderate-, 52% high-severity fires [173,174]|
|Thousand Lakes Wilderness1,2,3 (2,042-ha study area) |
|white fir-Jeffrey pine||1710-1995||x=4 years, range=1-20 years (composite); x=14 years, range=7-25 years (point)||4% low-, 44% moderate-, 52% high-severity fires; x fire size 145.7 ha, range 34-388 ha|
|1905-1995||too few intervals to compare|
|white fir-sugar pine (Jeffrey pine common)||1658-1995||x=9 years, range=2-35 years (composite); x=15 years, range=7-43 years (point)||2% low-, 35% moderate-, 63% high-severity fires; x fire size 103 ha, range 12-335 ha |
|1905-1995||too few intervals to compare|
|west-slope Carson Range, east-slope Lake Tahoe1(6,000-ha study area) |
|Jeffrey pine-white fir (1910-2300 m)||1650-1850||x=3.4-9.4 years (for 8 watersheds), range=1-36 years; range for widespread fire (≥6 watersheds)=3-31 years||90% dormant-season fires; no fires after 1871; from 1775-1850 widespread fires in driest years (P<0.01), fires in ≥2 to ≥6 watersheds preceded by 2-4 years wet weather (P<0.01); high moisture associated with nonfire years |
|Little Frying Pan drainage in Sweetwater Mountains of eastern CA1 (<40-ha study area) |
|Colorado pinyon-western juniper (Pinus edulis-Juniperus occidentalis)||1687-1895||x=8 years||"low-intensity" fire likely; from 1960-1996 fire size <0.1 ha; woody fuel buildup with lack of fire has increased crown fire potential in extreme weather |
|Yosemite National Park (prescribed fire natural areas) |
|Jeffrey pine||1972-1993||x=158 years||0.06% of Jeffrey pine forests burned in prescribed natural fires from 1972-1993, fire size 4-400 ha |
|Valentine Camp Natural ReserveÂ¹ |
|Jeffrey pine||1745-1889||x=9 years, range=4-17 years||last fire before 1900, but remains fairly open Jeffrey pine-dominated canopy; fires more frequent in Jeffrey pine than in red fir only 100 m away (P<0.05) |
|Dinkey Creek Watershed in southern Sierra Nevada1 (>2,070-ha study area, six 1.4-ha plots) |
|mixed conifer||1771-1873||x=3.2-5.4 years (by plot), range=1-12 years||high incidence of lightning, from 1911-1964 were 39 lightning-ignited fires (1/1.4 years), no fire >2.5 ha from 1911-1964 |
|Kings Canyon National Park1(160-ha study area) |
|yellow pine (Jeffrey pine and ponderosa pine)||1775-1909||x=3.5 years, x=11.4 years/individual tree||no fire after 1909 |
|Teakettle Experimental Forest1 (1,300-ha study area) .|
|old-growth mixed conifer (white fir dominant, but Jeffrey pine largest and tallest)||1614-1917||x=17.4 years (point), range=3-115 years||10 widespread fires from 1795-1865, after 1865 only 2 localized fires; greater number of fires in La NiÃ±a years (P<0.001) but proportion burned not different in La NiÃ±a years (P=0.77) .|
|1692-1865||x=11.4 years (composite, minimum 3 scars)|
|San Bernardino Mountains1 |
|Jeffrey pine||pre-1860||x=14 years||FRI significantly (P<0.05) longer from 1905-1974 than earlier time periods, ignitions primarily lightning |
|San Bernardino Mountains (68 plots) |
|Jeffrey pine and Jeffrey pine-white fir||pre-fire exclusion||x=15-30 years||stand structure and composition changes without fire discussed in Succession without fire |
|San Bernardino Mountains (45 plots of 10 Ã 30 m) |
|Jeffrey pine and Jeffrey pine-white fir||pre-1905||x=16 years|||
|San Bernardino Mountains |
|Jeffrey pine||1760-1904||x=12 yearsa||different subscripts, significantly different (P<0.05); annual area burned from 1940-1950 was 2,385 ha, from 1960-1970 was 1,528 ha |
|Sierra San Pedro MÃ¡rtir, Baja California Norte1 (~0.8 kmÂ²/forest type) |
|Jeffrey pine-mixed conifer||1700-1799||x=5.8-9.6 years (composite mean range from 1 fire scar to 3 fire scars and ≥25% of recording trees)||1% dormant-season, 42% early earlywood, 32% middle earlywood, 16% late earlywood, and 9.4% latewood scars|
|Jeffrey pine||1700-1799||x=3.9-10.1 years||52% early earlywood, 30% middle earlywood, 11% late earlywood, and 8% latewood scars |
Overall, fires scarring >10% of trees occurred when precipitation was low (P<0.01) and 2 previous years were wet (P<0.01, 1st year; P<0.05, 2nd year); possible causes of increased FRI after 1800s: livestock grazers reducing fine fuels and limiting fire spread and size, reduced size of native populations that burned landscape, and/or climate changes 
|Sierra San Pedro Martir2,4,5 (40,655 ha) |
|Jeffrey pine||1925-1990||x=45 years||436 fires < 16 ha, 41 fires > 800 ha and 2 fires>6,400 ha in size; long FRI attributed to slow fuel buildup and litter accumulation |
|Jeffrey pine-white fir||x=62 years|
|1Fire scars, 2age class distributions, 3radial growth, 4aerial photos, and 5vegetation and fire maps.|
Jeffrey pine occurs in a variety of habitats, many of which may not be listed in the above table. For additional information on FIRE REGIMES that may be relevant to Jeffrey pine, consult the table below:
|Fire regime information on vegetation communities in which Jeffrey pine may occur. For each community, fire regime characteristics are taken from the LANDFIRE Rapid Assessment Vegetation Models . These vegetation models were developed by local experts using available literature, local data, and/or expert opinion as documented in the PDF file linked from the name of each Potential Natural Vegetation Group listed below. Cells are blank where information is not available in the Rapid Assessment Vegetation Model.|
|Vegetation Community (Potential Natural Vegetation Group)||Fire severity*||Fire regime characteristics|
|Percent of fires||Mean interval |
|Minimum interval |
|Maximum interval |
|Pine savannah (ultramafic)||Replacement||7%||200||100||300|
|Surface or low||93%||15||10||20|
|Surface or low||78%||13|
|Mixed conifer (southwestern Oregon)||Replacement||4%||400|
|Surface or low||67%||22|
|California mixed evergreen (northern California)||Replacement||6%||150||100||200|
|Surface or low||64%||15||5||30|
|Vegetation Community (Potential Natural Vegetation Group)||Fire severity*||Fire regime characteristics|
|Percent of fires||Mean interval |
|Minimum interval |
|Maximum interval |
|Surface or low||78%||13|
|Mixed conifer (North Slopes)||Replacement||5%||250|
|Surface or low||88%||15||10||40|
|Mixed conifer (South Slopes)||Replacement||4%||200|
|Surface or low||80%||10|
|Surface or low||74%||30|
|Interior white fir (northeastern California)||Replacement||47%||145|
|Surface or low||21%||325|
|Red fir-white fir||Replacement||13%||200||125||500|
|Surface or low||51%||50||15||50|
|Sierra Nevada lodgepole pine (dry subalpine)||Replacement||11%||250||31||500|
|Surface or low||45%||60||9||350|
|Vegetation Community (Potential Natural Vegetation Group)||Fire severity*||Fire regime characteristics|
|Percent of fires||Mean interval |
|Minimum interval |
|Maximum interval |
|Great Basin Shrubland|
|Wyoming big sagebrush semidesert with trees||Replacement||84%||137||30||200|
|Surface or low||5%||>1,000||20||>1,000|
|Mountain big sagebrush with conifers||Replacement||100%||49||15||100|
|Mountain shrubland with trees||Replacement||22%||105||100||200|
|Surface or low||31%||250||50|
|Great Basin Woodland|
|Juniper and pinyon-juniper steppe woodland||Replacement||20%||333||100||>1,000|
|Surface or low||49%||135||100|
|Surface or low||78%||13|
|Great Basin Forested|
|Aspen with conifer (low to midelevation)||Replacement||53%||61||20|
|Surface or low||23%||143||10|
|Aspen with conifer (high elevation)||Replacement||47%||76||40|
|Surface or low||35%||100||10|
| *Fire Severities: Replacement=Any fire that causes greater than 75% top removal of a vegetation-fuel type, resulting in general replacement of existing vegetation; may or may not cause a lethal effect on the plants. |
Surface or low=Any fire that causes less than 25% upper layer replacement and/or removal in a vegetation-fuel class but burns 5% or more of the area.
Mixed=Any fire burning more than 5% of an area that does not qualify as a replacement, surface, or low-severity fire; includes mosaic and other fires that are intermediate in effects [50,78].
More info for the terms: basal area, climax, competition, cover, density, duff, eruption, fire exclusion, fire frequency, fire management, fire-return interval, frequency, fuel, litter, shrub, shrubs, succession, tree, ultramafic soils
Jeffrey pine is shade intolerant [7,63] and typically replaced by shade-tolerant conifers in the absence of canopy-opening disturbances [106,172]. On exceptionally harsh sites, Jeffrey pine may be a climax species [2,129].
Climax: Jeffrey pine forests restricted to ultramafic soils in the upper Illinois River drainage of Siskiyou Mountains in southwestern Oregon were considered an edaphic climax type . In the Sierra San Pedro MÃ¡rtir, Jeffrey pine/mountain snowberry vegetation is characterized as a "supramediterranean climax forest" .
Primary succession: In Lassen Volcanic National Park, a single Jeffrey pine occurred on a 10-year-old volcanic mudflow, highlighting its tolerance of early-seral conditions. Findings suggested that Jeffrey pine was more tolerant of early-seral, disturbed sites than of white fir competition and late-seral conditions. Jeffrey pine frequency and density were greater on 300-, 750-, and 1,500-year avalanche flows than in nearby white fir-dominated climax forests. On most flows, Jeffrey pine density was greatest on those plots closest to a seed source . In another study of debris flows created by the 1915 eruption of Lassen Peak, Jeffrey pine colonization of mud flows was continuous from at least 1940 to the date of the study (1987) .
Succession without fire: Numerous studies have investigated stand changes that occur in Jeffrey pine habitats in the absence of fire. Decreased Jeffrey pine recruitment, decreased Jeffrey pine importance, increased Jeffrey pine mortality, increased stand density, increased shade-tolerant conifer importance, and increased canopy closure are commonly described as succession proceeds without fire in mixed-conifer and/or Jeffrey pine-dominated stands.
Using historic photos, journals, and other sources, researchers found that decreased fire frequency together with timber harvests and intense grazing changed the composition and structure of northeastern California's eastside pine forests. Jeffrey pine and ponderosa pine forests studied in the late 1980s had greater small tree density, increased canopy closure, greater shrub density, more dead and downed material, more litter and duff, decreased stand age, reduced tree spacing, lower stand height, and less herbaceous vegetation than in presettlement time (~1850). The forest stand structure and fuel availability of forests in the late 1980s would likely support more severe fires than occurred in presettlement time .
Before fires were excluded in Lassen Volcanic National Park and the adjacent Caribou Wilderness, fires burned an average of every 11 years in Jeffrey pine habitats (Swanson 1980, cited in ). Frequent fires maintained disclimax Jeffrey pine and ponderosa pine forests by preventing the establishment of climax fir (Abies spp.) species. An abundance of fire-scarred Jeffrey pine and ponderosa pine in the area suggested that past fires burned quickly and with low intensity. Frequent low-severity fires maintained an open structure and uneven age distributions. Without fire, shrubs and white fir increase in the understory, providing ladder fuels that support crown fires .
In the Warner Mountains of extreme northeastern California, a lack of Jeffrey pine and ponderosa pine recruitment was attributed to thick litter and decreased sunlight due to increased white fir density. Changes in stand structure that were considered barriers to Jeffery pine and ponderosa pine recruitment were thought to be a result of fire exclusion and heavy grazing .
Contemporary Jeffrey pine-white fir forests had significantly greater Jeffrey pine density and basal area (P<0.05) and significantly smaller diameters (P<0.05) than presettlement (pre-1850) forests on the eastern shore of Lake Tahoe. Contemporary forests reflect postlogging succession during a long fire-free period (>120 years). Presettlement forests were reconstructed from stumps cut in early 19th century, and contemporary forest characteristics came from current stand measurements. White fir density in contemporary forests was about 3 times that of presettlement forests, and the diameter of white fir trees was significantly smaller in contemporary than presettlement forests .
In the San Bernardino Mountains, tree density increased in mixed Jeffrey pine, mixed white fir, and monotypic Jeffrey pine forests after 60 or more years of fire exclusion. Small-diameter tree importance increased and large-diameter tree importance decreased without fire. In mixed Jeffrey pine forests, average tree density was 93 stems/ha in 1929, and stands had heterogeneous diameter structure. Sixty-three years later, tree density was 167 stems/ha, dominance of juvenile trees increased, and the density of large trees (>26-inch (67 cm) DBH) decreased. In mixed white fir stands, there were 174 trees/ha in 1929 and 246/ha in 1992. Over this period, trees with DBH of 4.7 to 13 inches (12-33 cm) nearly tripled, and the number of large trees decreased by half. White fir was the overwhelming dominant, which was not the case in 1929. Jeffrey pine forests in 1929 were open and had heterogeneous diameter distributions. After fire exclusion, density of white fir and incense-cedar increased, and overall tree density increased by 114%. Stems with DBH measurements less than 26 inches (67 cm) increased, and stems with DBH over 39 inches (100 cm) decreased. Tree density increases were less dramatic in Jeffrey pine forests occupying dry, high-elevation sites. The fire-return interval during the fire exclusion period was estimated at 700 years .
When Jeffrey pine-white fir forests with different fire management were compared in the San Bernardino Mountains of southern California and in La Corona Arriba in Baja California Norte, forests subject to fire exclusion in the San Bernardino Mountains had more Jeffrey pine mortality, nearly double the adult tree density, and more live and dead tree basal area than those in La Corona Arriba. Forests in the San Bernardino Mountains did not burn for about 90 years, while there was no policy of fire exclusion in La Corona Arriba. There were significantly more standing dead Jeffrey pine in southern California than in Baja California (P<0.05), and mortality was primarily a result of severe drought conditions and bark beetle attacks in southern California. Weather data from Big Bear Dam indicated that the lowest precipitation levels on record were for 2 years in the late 1990s. Researchers suggested that the density and basal area differences between the 2 sites were due to decreased fire frequency in the San Bernardino Mountains, and that increases in tree density and basal area increased the forest's susceptibility to drought and insects . When Jeffrey pine forests in the San Bernardino Mountain sites were compared to those in Sierra San Pedro MÃ¡rtir in Baja California Norte, findings were similar. Adult tree density and basal area in the San Bernardino Mountains were nearly double that of the Sierra San Pedro MÃ¡rtir. Most sites in the San Bernardino Mountains had not burned since 1905. There were 3 times as many standing dead Jeffrey pine and white fir in southern California as in Baja California. Most trees in southern California established in the last 100 years; the maximum age of Jeffrey pine was around 285 years in southern California, whereas the oldest Jeffrey pine tree in the Sierra San Pedro was 448 years old .
Succession after logging: Jeffrey pine cover increased with time since clearcut logging in red fir forests of the central Sierra Nevada, and Jeffrey pine growth increased on thinned, mixed ponderosa pine-Jeffrey pine stands in northeastern California's Black Mountain Experimental Forest. Cover of Jeffrey pine was significantly higher in 11- to 32-year-old than in 4- to 10-year-old clearcuts (P<0.05) in red fir forests. Cover averaged 0.04%, 1.6%, and 1.9% in 4- to 10-year-old, 11- to 25-year-old, and 26- to 32-year old clearcuts, respectively . After 55-year-old ponderosa pine-Jeffery pine stands in northeastern California were thinned from about 11,000 trees/acre to around 700 trees/acre, pine tree height on thinned stands was 62% and DBH was 167% of unthinned stands 5 years after treatment. Twelve years after treatment, tree height was 38% and DBH was 43% greater on thinned than unthinned stands. Thirty years after treatment, tree height was 39% and DBH was 91% greater on thinned than unthinned stands .
Jeffrey pine reproduces sexually through seed production and germination. Trees do not sprout after the loss of aboveground stems.
Pollination: Cones are wind pollinated.
Breeding system: Jeffrey pines are monoecious. A study of endemic and near-endemic California conifers revealed that Jeffrey pine was the most genetically diverse . Outcrossing rates were high in 3 Klamath Mountain and 2 Sierra Nevada populations. Density of Jeffrey pine did not affect outcrossing rates, and evidence of severe inbreeding depression was lacking . Jeffrey pine populations from serpentine soils in the Klamath Mountains and ultramafic soils in the southern Sierra Nevada were genetically similar, suggesting that directional selection likely has occurred on these sites. Klamath Mountain populations had lower heterozygosity levels than those in the southern Sierra Nevada, suggesting stronger directional selection or a past population bottleneck in the Klamath Mountain populations .
Seed production: Jeffrey pine has a "strong masting habit". Numerous seeds are shed within a few weeks every several years. Large cone crops occur at 2- to 4-year intervals [77,84]. Trees as young as 8 years old have produced cones, according to Krugman , but Rundel  reports that Jeffrey pine cones are not common until trees are at least 20 years old. In open Jeffrey pine/antelope bitterbrush forests in western Nevada's Whittell Forest and Wildlife Management Area, cone crop production ranged from 175 to less than 25 cones/tree over a 3-year period . From cones produced on the eastern slopes of the Sierra Nevada in Mono and Madera counties, the number of fertile seeds/cone before seed dispersal averaged 222 and ranged from 160 to 338. From fallen cones collected at the end of April, the number of seeds/cone averaged 11 and ranged from 0 to 55. Of the available seeds, 14.8% were sound, 15.9% were aborted, and 69.2% had insect damage .
On eastern Sierra Nevada slopes in Lassen County, seed size and number were positively related to cone size, and seed size varied with position on the cone. Cones came from young, "thriftily growing" trees. Seed number and seed weight were greatest for large- and least for small-sized cones. For large cones, the largest number of developed seeds were concentrated in the middle cone region. For small cones, the largest number of developed seeds occurred in the upper cone region .
Seed survival is largely augmented by seed caching and seed feeding by small mammals and birds. The following studies conducted in western Nevada showed that, while seed removal rates may vary by seed availability and environment, removal is nearly complete regardless. In the Whittell Forest and Wildlife Management Area, the removal rate of radioactively-labeled Jeffrey pine seed from an open Jeffrey pine/antelope bitterbrush stand was 8.1 times faster in a mast than in a nonmast year (P<0.0001), but in any year, 98% to 99% of seeds were harvested. Of the removed seeds, a little more than 63% were found in rodent caches. The rest were either consumed or cached outside the study area. Yellow-pine chipmunk caches were most common, but a small percentage of caches were likely made by golden-mantled ground squirrels . Seed removal rates did not consistently vary by elevation. Over a 2-year period, removal rates ranged from a low of 10.3%/day to a high of 71.7%/day at low-elevation sites. At midelevation sites, rates were not different between years, and at high-elevation sites rates ranged from 16.5% to 58.2%/day . Along a transect through antelope bitterbrush shrublands with scattered Jeffrey pine into closed-canopy Jeffrey pine forests with thick litter, removal of Jeffrey pine seed was significantly faster in shrublands than in Jeffrey pine forests (P<0.005). Seed obscured by litter were removed at significantly slower rates than seed on the soil surface (P<0.001). Regardless of seed location, the researcher predicted that most (≥99%) seed would be removed before snowfall . The movement and fate of seed cached in western Nevada is discussed below in the Seed dispersal, Seed banking, Germination, and Seedling establishment sections.
Seed dispersal: Jeffrey pine seeds are often moved through a combination of methods including gravity, wind, and small animals. A single seed may be dispersed through all 3 methods and relocated up to 6 times by animals. Observed and calculated dispersal distances through gravity and wind alone range from 3.48 feet (1.06 m)  to 89 feet (27 m) . Dispersal distances reported from seed caching studies range from 8.5 feet (2.6 m)  to 206 feet (62.9 m) .
Gravity and wind: Of the North American conifers that produce winged seeds, Jeffrey pine seeds are typically heaviest. Without strong winds, the majority of seeds fall within 90 feet (27 m) of the parent tree . However, observations in the field suggest much shorter dispersal distances . If winds are gusty, Jenkinson  suggests that Jeffrey pine seed may be dispersed a distance 15 times the height of seed fall. Based on ballistics calculations, Jeffrey pine seeds falling from a height of 30 feet (10 m) in winds of 5 m/s would be deposited 55.4 feet (16.9 m) from the source .
In the Whittell Forest and Wildlife Management Area, wind rarely moved seeds already on the ground more than 8 inches (20 cm) from their original positions. The study was conducted in Jeffrey pine/antelope bitterbrush vegetation on nearly flat to slightly inclined terrain with sandy soils with small rocks and patches of plant litter. The maximum dispersal distance was 150 inches (380 cm) from the initial position. Most movement occurred within the first 8 of 37 monitoring days. Under natural conditions, wings often detach after a seed is wet or moved; permanent wings in this study may have increased the dispersal distance beyond what would have occurred under natural conditions .
Animal: Yellow-pine chipmunks rapidly dispersed and cached Jeffrey pine seeds from Jeffrey pine/antelope bitterbrush vegetation in western Nevada. From a bait station seed source, 0.5% of radioactively-labeled seeds were eaten and 98.1% were cached. The average number of seeds in cheek pouches ranged from 18.5 to 29.9 based on 4 yellow-pine chipmunks. There were 36 to 91 caches made with 3 to 9.9 seeds. Caches were separated by distances of 4.6 to 16 feet (1.4-4.9 m). Transport distance ranged from 8.5 to 195 feet (2.6-59.3 m) and averaged 82 feet (25 m). Yellow-pine chipmunks typically cached seeds more than 16 to 33 feet (5-10 m) from the source and only "sparingly" cached in areas with thick pine needle litter . In the same study area using similar methods, Vander Wall  found that seeds were moved farther in a mast (x=87.9 feet (26.8 m)) than in a nonmast (x=68.2 feet (20.8 m)) year. Often seeds were moved from primary caches to secondary or up to sixth-order caches. Recaching was 3 times more common in a nonmast than in a mast year. In a mast year, the highest order cache was 3, and in a nonmast year was 6 .
Dispersal of Jeffrey pine seed was affected by habitat in the Whittell Forest and Wildlife Management Area. Radioactively labeled Jeffrey pine seed was scattered to simulate seed dispersed by wind from 2 source trees. Source tree 1 occurred in a forest clearing with deep soils and low herbaceous and litter cover. Source tree 2 was in a sparsely forested site with thin soils, boulders, and rock outcrops. There were 1,064 seeds/source tree, and 95% or more were removed within 43 hours. Three percent or less were consumed. Most caches were small, with 1 to 4 seeds, but caches with up to 35 seeds were found. The distance between caches and source tree 1 ranged from 4.3 to 178 feet (1.3-54.2 m), and from source tree 2 the distance ranged from 20 to 206 feet (6.2-62.9 m). Yellow-pine chipmunks were the most common harvesters . Yellow-pine chipmunk caching was twice as probable in antelope bitterbrush habitats and 1/6th as likely in Jeffrey pine forests than expected based on the proportion of these habitats available (P<0.001). In antelope bitterbrush habitats, over 50% of caches were in the open (>4 inches (10 cm) from shrub), 12% to 16% were under shrub canopy, and 28% to 35% were at the canopy edge. Most caches (66-73%) were in mineral soil, 24% to 27% were in light litter (<5 mm thick), and 3% to 7% were in thick litter (>5 mm). In the Jeffrey pine forests, a high proportion of caches (63-100%) were under mature tree canopies of 75% to 86% closure and in thick (2-4 inches (5-10 cm)) plant litter .
Clark's nutcrackers disperse and bury Jeffrey pine seeds, and unrecovered caches are important to successful seedling germination and establishment. On the eastern slopes of the Sierra Nevada in Mono and Madera counties, Jeffrey pine seed harvesting began in early to mid-September, and seed was stored from mid-September through mid-October. Clark's nutcrackers assessed seed quality from the sound made when shaken against their mandibles, ensuring that sound seeds were cached. They used their bills to dig shallow trenches a few centimeters long, where 1 to 15 seeds were cached. Caches were often made at tree bases, near rocks, and in other sites where snow melt was early. Open pumice substrates were preferred over pine needle litter as cache sites. Caches were 4 to 120 inches (10-300 cm) apart . For additional information on the utilization of Jeffrey pine by Clark's nutcracker, see Birds.
Seed banking: Jeffrey pine seed banks are predominantly unrecovered animal caches. Substrate and environmental conditions affect cache recovery. Field experiments conducted in the Whittell Forest and Wildlife Management Area showed that increased moisture levels increased the success of yellow-pine chipmunks and deer mice in finding caches made by other individuals. When conditions were dry, animal subjects were much less likely to recover caches other than their own . However, dry conditions that may hamper cache recovery would not likely be conducive to seed germination.
In a laboratory study, yellow-pine and long-eared chipmunks trapped from the Carson Range in Washoe County, Nevada, found just 2.3% of caches made in ash, while they found 98% of caches in sand. When chipmunks were allowed to cache seed themselves, the average number of caches made in ash was significantly more than caches made in sand (P=0.02). Researchers suggested that seeds were likely located by smell with more ease in sand than in ash, and that caching in ash may have been an attempt to decrease pilfering .
Germination: Jeffrey pine seed germinates readily in the spring , and while stratification may not be necessary [77,168] it can decrease the time required for successful germination . The best germination is said to occur in mineral soils in full sun conditions . Seed burial and cache site selection by small mammals and Clark's nutcracker can improve the emergence success of Jeffrey pine seed.
Temperature and stratification: Stratification of Jeffrey pine seed from northeastern California decreased germination time. Seed was air dried and stored at 30 Â°F (1 Â°C) for 2 to 3 years before being stratified for 3 months at 40 Â°F (5 Â°C). At a temperature of 77 Â°F (25 Â°C), stratified seeds reached 50% germination after 3 days and unstratified seeds after 23 days. As germination temperatures decreased, the differences in germination rates of stratified and unstratified seeds increased. At 59 Â°F (15 Â°C), 50% germination was reached after 6 days for stratified and after 115 days for unstratified seed. At 40 Â°F (5 Â°C), 50% germination was reached after 50 days for stratified and after 175 days for unstratified seed . Long-term storage of Jeffrey pine seed collected from Lassen National Forest did not affect germination rates. Germination of fresh seed averaged 65% after 3 months of stratification at 40 Â°F (5 Â°C), and seed stored for 8.5 years averaged 67% when stratified at same temperature .
Seed/cone size: Percent germination decreased with seed size, which related to cone size (see Seed Production), on the eastern slope of the Sierra Nevada in Lassen County. Germination was most rapid for the largest seeds from the largest cones and slowest for the smallest seeds from the smallest cones. Germination period differed by 2 weeks for large and small seeds .
|Cached seed: Emergence is typically more successful when seeds are buried in caches than when unburied. A multitude of experiments have investigated the fate of seeds from caches in western Nevada. When seeds were buried to mimic yellow-pine chipmunks caches and protected from small mammals, 55.2% of buried seed emerged. Just 1 of 100 seeds left on the soil surface produced seedlings. Burial by ant activity likely aided germination of the seed on the soil surface . |
Germination and seedling emergence were affected by cache site environment and substrate in western Nevada. Emergence from rodent caches was greatest at mid- and low-elevation sites, but seedling survival was best at mid- and high-elevation sites. Emergence of seeds planted in an exclosure did not differ between shade and full sun conditions (P≥0.1) at any elevation . For a discussion of climate differences at these low-, mid-, and high-elevation sites, see Climate.
|Charles Webber Â© California Academy of Sciences|
While canopy cover did not affect seeds in exclosures, it affected emergence from scatter-hoard caches in open Jeffrey pine/antelope bitterbrush plots. About 50% of seedlings emerged in open sites over 4 inches (10 cm) from the nearest shrub, 20% emerged beneath shrub canopies, and 29% emerged at shrub canopy edges. More seedlings emerged at the canopy edges than in the open based on the proportion of the habitats available (P<0.001). There were 48 to 528 emergence sites/100 mÂ². Seedlings emerged singly, in clumps of 2 to 7, and less commonly in large clusters of up to 54. Excavations of random emergence sites revealed that nearly 9% of cached seeds failed to emerge. Emergence sites were concentrated on mineral soil (75%), but litter was low in the general study area . Seedling survival is discussed in Seedling establishment/growth below.
Jeffrey pine seedling establishment may be greatest on burned sites with exposed mineral soil. Seedling emergence from artificial caches of depths of 0.2 and 1 inch (5 mm, 25 mm) was significantly greater on burned than unburned plots (P=0.002) in pine forests near Lake Tahoe. Seeds planted in ash 1 month after fire produced 14.8 times more seedlings than seeds planted on unburned plots. Caches made in soil produced 3.5 to 8.5 times more seedlings than caches in pine needle litter on the soil surface. Seed removal rates were lower on burned than unburned sites for 1 to 5 months after fire, and seedlings on burned sites survived 1.9 times longer than on unburned sites . For additional information on seedling establishment on burned sites, see Seed caches on burned sites.
Seedling establishment/growth: Jeffrey pine seedling survival may be affected by canopy cover, weather patterns, associated species, and/or pest infections. Jeffrey pine regeneration is not considered rapid or reliable . Likely a combination of these factors limits and/or encourages recruitment in any year.
Canopy cover: In mixed-conifer forests on the Teakettle Experimental Forest, Jeffrey pine seedlings (≤19 inches (49 cm)) and saplings (≥20 inches (50 cm)) were under open canopies. In the study area, Jeffrey pine seedling density averaged 10/ha and was 0.4% of the total conifer seedling composition. There were 4 saplings/ha, which was 0.9% of the total conifer sapling composition. Jeffrey pine seedling and sapling densities in whitethorn ceanothus-dominated patches were slightly greater than 10/ha, and in closed-canopy forests were less than 10/ha. Most Jeffrey pine seedlings and saplings occurred in dry, open areas with high light levels. Most seedlings (>50%) grew in forest floor litter, but a little more than 20% grew in mineral soil [42,120].
Weather: Jeffrey pine seedling establishment was associated with precipitation on the Teakettle Experimental Forest and Lassen National Forest. However, annual precipitation analyses were used in the Experimental Forest study, and seasonal precipitation was used in the National Forest study, making comparisons difficult. In the 3,200-acre (1,300 ha) Experimental Forest study area, Jeffrey pine recruitment was associated with wet years (Palmer Drought Severity Index was 2.36). Nearly all Jeffrey pine established before 1865 in wet years during or shortly before an El NiÃ±o year . In Lassen National Forest meadows, establishment of Jeffrey pine was most likely when spring temperatures were cool and summer precipitation was below normal. Establishment was least likely when spring temperatures were normal. On 4 meadows, there were 1.8 to 204.5 Jeffrey pine seedlings, 1.8 to 47.3 saplings, and 18 to 166 trees. Seedlings, saplings, and trees were counted along downslope transects ranging from 140 to 960 feet (43-290 m) from forest to meadow .
Associated species: Antelope bitterbrush was a nurse plant to Jeffrey pine seedlings in western Nevada, and woolly mule-ears interfered with Jeffrey pine seedling establishment in eastern California.
Nurse plants: Antelope bitterbrush was important to Jeffrey pine seedling survival in Nevada's Whittell Forest and Wildlife Management Area. Mortality of seedlings established in the spring of 1989 was 85% by the fall of 1990. Single seedlings became increasingly common with each successive sampling season due to deaths within seedling clumps. Single seedlings survived at a significantly higher rate than clumped seedlings (P<0.05), and herbivore browsing was more common on clumped than single seedlings (P<0.05). Most mortality (62%) was due to summer desiccation. Mortality rates were greatest on plots with the greatest forb and cheatgrass (Bromus tectorum) densities. Single seedlings under antelope bitterbrush canopies survived significantly better than seedlings in the open (P<0.001), and seedling clumps under shrub canopies had significantly greater potential of producing at least 1 survivor than did clumps in the open (P<0.001). Increased seedling survival under antelope bitterbrush was likely due to decreased temperature, lower moisture stress, and herbivory protection. It is unknown if canopy cover benefits seedlings over 2 years old .
Interference/allelopathy: Jeffrey pine seedling survival and growth were greater on montane chaparral than woolly mule-ears-dominated sites on the east slope of Boca Hill near Truckee, California. One-year-old seedlings grown from locally collected seed were planted in the spring of 1978 and evaluated 5 and 8 years later. Survival was significantly greater 5 and 8 years later (P<0.005 and P<0.02, respectively) in montane chaparral than in woolly mule-ears vegetation. Seedling height was also significantly greater 5 and 8 years later (P<0.005 and P<0.001, respectively) in montane chaparral than in woolly mule-ears vegetation .
Other studies have investigated possible reasons for decreased survival and growth of Jeffrey pine in woolly mule-ears vegetation. In the laboratory, seeds watered with woolly mule-ears root and leaf extracts had significantly less radicle growth (P<0.01 and P<0.05, respectively) than seeds watered with distilled water. Jeffrey pine seeds stratified in woolly mule-ears vegetation in the Sagehen Basin had significantly less radicle growth (P<0.01) than seeds stratified in areas free of woolly mule-ears litter. Germination was also lower for seeds stratified on sites with woolly mule-ears litter than on sites without litter and for seeds watered with root and leaf extracts than for seeds watered with distilled water. Jeffrey pine roots in areas with woolly mule-ears had less mycorrhizal infection than did roots grown without woolly mule-ears, which may have affected regeneration success . Other researchers suggested that neither allelopathy nor soil nutrients affected Jeffrey pine seedling growth in woolly mule-ears sites in the northern Sierra Nevada of Plumas County. Jeffrey pine seed germination and seedling growth were compared in soils collected from early-seral, woolly mule-ears-dominated sites, midseral, shrub-dominated sites, and late-seral Jeffrey pine-dominated sites. Germination was not significantly different by soil type and averaged about 95%, although early-seral soils had the lowest organic horizon depths and lowest levels of carbon, calcium, and magnesium. After 417 days, seedlings in early- and midseral soils had more mass than those in late-seral soils .
Dwarf mistletoe: In California, dwarf mistletoe (Arceuthobium spp.) can cause heavy mortality in Jeffrey pine seedlings and saplings. Twenty percent fewer seeds germinated from infected than uninfected Jeffrey pine trees, and seedlings produced from infected tree seed were deemed less "vigorous" than those from uninfected tree seed .
Growth: Growth of Jeffrey pine seedlings, saplings, and trees is reported from a variety of studies and sites. Growth and survival can be affected by canopy cover and stand density. In a greenhouse study, the relative growth rate of Jeffrey pine seedlings between 2 and 10 weeks old averaged 26.6 mg/g/day. A maximum growth rate of 38.5 mg/g/day was reported . In old-growth mixed-conifer forests of the Lake Tahoe Basin, importance of Jeffrey pine saplings over 5.9 inches (15 cm) tall, but under breast height was positively correlated with Jeffrey pine canopy cover (P<0.0005). There was no negative correlation with other canopy tree species .
Radial stem growth of Jeffrey pine averaged 20 μm/day at elevations of 7,900 to 8,900 feet (2,400-2,700 m) on the Kern Plateau of the southern Sierra Nevada. Growth was averaged over size class, site, and year. Total annual radial growth averaged 1.4 mm/year. Jeffrey pine had measurable radial stem growth for an average of 66 days. The growing season increased significantly on south slopes (P<0.001). Sapling growth was proportional to daily maximum and average daily temperatures (P<0.005), but this was not true for large Jeffrey pines . Small Jeffrey pines (<16 inches (40 cm)) were most common at low elevations (5,090 to 5,710 feet (1,550-1,740 m)) on the Carson Range of western Nevada. Most large trees occurred at mid- (6,560-6,730 feet (2,000-2,050 m)) or high elevations (7,495-8,020 feet (2285-2445 m)). Tree density was usually greatest at midelevation sites. The number of dead trees was highest (19/ha) at low-elevation sites. At mid- and high-elevation sites the number of dead Jeffrey pine averaged 2.8/ha and 2.6/ha, respectively. Average radial growth rates of trees older than 30 years was positively correlated with elevation and negatively correlated with tree density (RÂ²=0.420, P<0.001). Mid- and high-elevation Jeffrey pine growth rates were 54% and 62% greater, respectively, than low-elevation growth rates .
Vegetative regeneration: Jeffrey pine does not sprout from adventitious buds or spread through vegetative means. However, regrowth of needles from surviving terminal buds can occur following crown scorch . For more on this, see Terminal bud regrowth.
Growth Form (according to Raunkiær Life-form classification)
More info for the term: phanerophyte
RAUNKIAER  LIFE FORM:
Reaction to Competition
As a result of wildfire, stagnated sapling stands of naturally regenerated Jeffrey and ponderosa pines are common in the 1.6 million ha (4 million acres) of yellow pine forests in northeastern California. Densities have sometimes reached 42,000 stems per hectare (17,000/acre). Growth is so slow that stand development virtually ceases, yet dominants and codominants can respond to thinning. In one 55-year-old stand with 27,200 stems per hectare (11,000/acre), thinning 2.5-m (8.2-ft) tall saplings to a spacing of 2.7 m (9 ft) tripled their periodic radial growth and increased height growth 67 percent in 5 years, compared with unthinned controls (53).
Survival and growth of planted Jeffrey pine reflects the thoroughness of site preparation and post-planting protection against aggressive understory plants (42,43). Heavy invasion of any vegetation soon after planting makes seedling survival unlikely, if not impossible. Brush, grasses, and sedges all are lethal competition for available soil water in Jeffrey pine's dry summer environments, and many shrub species quickly overtop and markedly slow the growth of surviving seedlings.
Low vegetation even reduces the growth of established Jeffrey pine. In northeastern California, removing perennial bunchgrass and sedge, alone or together with sagebrush (Artemisia tridentata) and bitterbrush (Purshia tridentata), increased the mean 5-year basal area increment of pine poles by as much as 38 percent (18).
Life History and Behavior
Female cones develop shortly after male cones, and fertilization of Jeffrey pine occurs about 13 months after pollination . Female cones are pollinated from May to July, cones ripen from August to September of their second year, and seeds are dispersed from September to October [49,77,112,211]. Trees at low-elevation sites often shed pollen earlier than trees at high-elevation sites . Phenological development of 10 young Jeffrey pine trees (3-6 feet (0.9-2 m) tall) on sites at about 5,300 feet (1,600 m) on the western slope of Sierra Nevada in the Stanislaus National Forest was monitored for 7 to 8 years. The average date that growth began was 16 May. The growing season averaged 78 days, and the average minimum number of days to reach 50% of total annual growth was 21 .
In forest tree nurseries in northern California and southern Oregon, seeds are sown in April to utilize the full growing season. Germination is epigeal (30). Stratified seeds are sown above a maximum depth of 6 to 8 mm (0.25 to 0.30 in) and at a density to produce 269 to 323 seedlings per square meter (25 to 30/ft²) . Fertilization and irrigation regimes are tailored to seedling requirements in the particular nursery soil and climate. For most sources west of the Sierra-Cascade crest and in southern California, seedlings of plantable size are raised in one growing season. For many sources east of the crest, seedlings are often carried through two seasons.
To consistently raise large and healthy seedlings of Jeffrey pine, nursery soil management is crucial. In midsummer, dry, fallow soil is ripped deeply enough to restore rapid drainage and aeration, and then fumigated. Fumigation is necessary to control nematodes, root rots such as Rhizoctonia, Phytophthora, Pythium, Macrophomina, and Fusarium spp., and foliar diseases such as Phoma and Sirococcus (38).
Jeffrey pine is quickly established in the field when dormant seedlings are lifted from nursery beds at the right time in winter, held in cold storage, planted at the right time in spring, and protected against animal damage and competing vegetation. Lifted seedlings are root-pruned 23 cm (9 in) below the cotyledon scars and stored in polyethylene-lined bags at 1° C (34° F). Planting starts at the onset of spring conditions, when soils warm sufficiently to permit water uptake and root growth. Planting is ideally completed before the last spring rain to ensure that roots will be sealed in the soil. In the Sierra Nevada, field survivals of 90 to 99 percent are attainable on cleared sites within the species' elevational range (27).
Seed Production and Dissemination
When shed, the winged seeds drop about 2.2 m/s (7.2 ft/s) (49), indicating that winds of 8 km/h (5 mi/h) carry them no further than the height of seedfall. Seeds can be widely spread, however. Fall storms are common in California's mountains, and winds average 13 to 26 km/h (8 to 16 mi/h) in September and October. Gusts occasionally exceed 64 to 113 km/h (40 to 70 mi/h), enough to blow seeds up to 15 times the height of seedfall, even 750 m (2,460 ft) from a tree height of 50 m (164 ft).
Besides wind, certain seed eaters also disseminate seeds. In the Sierra Nevada, Clark's nutcracker harvests and stores substantial quantities of ripe Jeffrey pine seeds, burying them in many small clusters in a wide variety of microsites, and often where snow accumulates least and melts rapidly in spring (54). At least eight other common birds also extract and eat seeds of Jeffrey pine.
Several kinds of squirrels cut and store large quantities of Jeffrey cones for their seeds, including the widespread golden-mantled ground squirrel and western gray squirrel. The chickaree cuts whole cones and buries them in the ground, and chipmunks harvest seeds by gnawing cones in the tree. Mice and voles efficiently gather, cache, and consume large quantities of shed seed.
Like seeds of most pines in temperate climates, Jeffrey pine germinates quickly the spring after seedfall. For starting new stands after harvest, however, natural regeneration is seldom quick and never reliable. The usual cause of failure is vegetation in the original understory that simply preempts the site. Irregular seed crops, poor seed dissemination, seed predators, cutworms, pathogens, mammals, and drought are also lethal factors (16,25).
Flowering and Fruiting
Unripe cones are pale or dark purple to black and shade to light brown or dull purple at maturity. Seeds are mature when cone specific gravity (fresh weight basis) drops to between 0.81 and 0.86; they are safely collected in stands where one or two trees have cones that are cracking, with seed scales separating. Mature cones are usually 13 to 23 cm (5 to 9 in) long, open to resemble old-fashioned straw beehives or skeps, and normally shed most of their seeds in September or October (30).
Growth and Yield
Table 1- Growth of Jeffrey pine and ponderosa pine in the Tuolumne River watershed of the western Sierra Nevada¹
Species Plantation Age Tree Height Stem diameter Leader length Height increase yr m cm m pct Jeffrey pine 11 2.15 4.3 0.44 26 20 7.05 16.2 0.56 9 Ponderosa pine 11 3.64 8.9 0.43 13 20 7.19 17.8 0.49 7 yr ft in ft pct Jeffrey pine 11 7.1 1.7 1.4 26 20 23.1 6.4 1.8 9 Ponderosa pine 11 11.9 3.5 1.4 13 20 23.6 7.0 1.6 7 ¹Seedlings were planted on cleared sites at an elevation of about 1650 m (5,400 ft) in 1962. After 5 years in the Plumas test, every stock class of Jeffrey pine gradually overtook its ponderosa counterpart, averaging 127 cm (50 in) tall and exceeding ponderosa pine by 5 percent 9 years after planting (15). In the Stanislaus plantation, Jeffrey pine accelerated growth into the pole stage, increasing height by one-fourth at 10 years, and at 20 years had nearly overtaken ponderosa pine in both height and diameter (table 1). Leader length at 20 years was 14 percent greater for Jeffrey pine, indicating that the species' difference might soon be eliminated. In the Modoc plantation, trees averaged 5 m (16.5 ft) tall and 15 cm (6 in) in diameter when thinned at 30 years (34,35). At thinning and for the next 15 years, the growth of these poles was apparently the same for both species. When seedlings of Jeffrey and ponderosa pines from the Sierra Nevada were planted at 560 m (1,830 ft) in the North Coast Range in Mendocino County, CA, the Jeffrey pines outgrew ponderosa pines from comparable elevations, edging them in both height and diameter in 17 years (6).
Jeffrey pine may live 400 to 500 years and on the best sites can reach an impressive size. Trees larger than 152 cm (60 in) in d.b.h. were often measured in virgin forests east and west of the Sierra-Cascade crest. The largest known survivor is on the Stanislaus National Forest in the western Sierra Nevada and measures 229 cm (90 in) in diameter and 53 m (175 ft) tall (36). Yellow pines taller than 61 m (200 ft) are recorded in early volume table measurements, and some of them probably are Jeffrey pine (24).
Several general accounts state that Jeffrey pines 1.2 to 1.8 m (4 to 6 ft) in diameter and 52 to 61 m (170 to 200 ft) tall were typical of the species' best growth on deep, coarse-textured and well-drained soils (28,45,52). Stands of similar description may still be seen in the high country of Yosemite National Park. By contrast, stand productivity is low for Jeffrey pine on ultramafic soils. Dunning's site index (base age 300 years) may often be as high as 29 m (95 ft), but the typical stocking capacity is just 11 to 28 percent of normal basal area (33).
Yield data have never been acquired specifically for Jeffrey pine, but Jeffrey pine apparently grows to the same age and maximum size as ponderosa pine. Observations in mature natural stands bolster the belief that yield data for ponderosa pine can be confidently applied to pure stands of Jeffrey pine, or to Jeffrey pine mixed with ponderosa pine (24,25).
Molecular Biology and Genetics
Barcode data: Pinus jeffreyi
Statistics of barcoding coverage: Pinus jeffreyi
Public Records: 4
Specimens with Barcodes: 16
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Reasons: This is primarily a pine of California, its range covering the entire length of the state and extending into Baja California, Mexico.
Please consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status (e.g. threatened or endangered species, state noxious status, and wetland indicator values).
Pests and potential problems
Squirrels, mice, moles, and birds consuming large amounts of Jeffrey pine seeds. Some of the biological agents attacking Jeffrey pine are two (2) needle diseases, a limb canker, as well as at least five (5) different rusts, three (3) root diseases and various heart rots. The worst disease of Jeffrey pine is caused by western dwarf mistletoe.
The Jeffrey pine beetle is common throughout its range, is the single worst enemy of the Jeffrey pine and has caused extensive mortality in mature trees. Other insects that damage Jeffrey pine include twig and needle scales, defoliators, stem and twig borers, tip moths, and cone and seed feeders.
Many pathogens and insects infect Jeffrey pine trees, but rarely is Jeffrey pine mortality
attributed entirely to a single infection. Often harsh growing conditions
cooccur with disease and insect outbreaks. In "pristine" mixed-conifer forests in
the Sierra San Pedro MÃ¡rtir, the overall incidence of diseases and insects on
Jeffrey pine averaged 21%. Needle cast was the most common pathogen, and Jeffrey
pine beetle the most common insect . In long unburned mixed-conifer forests
on the Teakettle Experimental Forest, Jeffrey pine mortality in the 8- to
20-inch (20-40 cm) DBH size class was significantly more than expected (P<0.05)
based on the size class proportion in the area. Of trees in the high-mortality
size class, mortality was significantly greater (P<0.05)
in high tree density areas (x=1,000 trees/ha).
Most mortality was related to pest or disease infections, and
many trees had several types of infections. Researchers suggested that diseases
and pests may function as the primary source of forest turnover when fire is excluded .
There are numerous potential Jeffrey pine root diseases. For the signs
and symptoms of Jeffrey pine root diseases, possible management strategies,
and impacts of fuel treatments, see Rippy and others . Jeffrey pine is also a
potential host to several dwarf mistletoe species, although western dwarf mistletoe
(Arceuthobium campylopodum) is most common. Dwarf mistletoe is capable of causing "considerable damage"
to Jeffrey pine . In California, dwarf mistletoe may cause high levels of
mortality in Jeffrey pine seedlings and saplings. Seeds from infected trees
can have lower germination rates than seeds from uninfected Jeffrey pine trees,
and seedlings from infected tree seed can be less "vigorous" than
seedlings from uninfected tree seed . For more on the identification and
host preferences of mistletoes, see Hawksworth and others . Dwarf mistletoe management
options are described by Kimmey  and Scharpf and others . Scharpf and others
indicate that tree mortality is often a result of 2 or more pests, and all agents should be
recognized and managed. For more on the insects and pathogens of Jeffrey pine forests,
consult Jenkinson  and Parker and others .
Many researchers suggest that prior injury and/or stressful growing
conditions increase the likelihood of subsequent Jeffrey pine infections and/or
mortality [73,148], but not all researchers agree . Pine engravers utilize
Jeffrey pine as a host in some areas, but extensive mortality is
rare. Researchers suggest that previously damaged trees, trees in dense stands,
and trees suffering drought effects are often targeted by the pine engraver . In South Lake
Tahoe, California, Jeffrey pine mortality was greater with both Elytroderma fungal disease and
Jeffrey pine beetle attacks than when trees were infected
with either pest alone . On the Susan River Watershed in Lassen National Forest,
western and Jeffrey pine beetles did not preferentially attack weakened Jeffrey
pine trees. More "apparently healthy" than weakened Jeffrey pine trees were attacked. The researcher
noted that these results occurred in other areas as well .
Jeffrey pine is susceptible to ozone damage. Greenhouse studies revealed damage and decreased
growth in 2- to 3-year-old Jeffrey pine seedlings exposed to ozone [100,176].
Of 13 western conifer species exposed to ozone, Jeffrey pine Ã Coulter pine hybrids were most sensitive, and Jeffrey pine
was third . In Jeffrey pine stands in the Giant Forest region of
Sequoia National Park, 90% of Jeffrey pine showed visible injury from ozone. Monthly averages of
ozone were 30 to 70 ppb-hour over a year, and were highest during
the growing season. Jeffrey pine recruitment was still occurring in all stands .
Simulation modeling was used to
predict changes in forest structure, composition, and FIRE REGIMES with
projected future temperature and precipitation changes in the Sierra Nevada.
Modeling indicated that species composition, forest
biomass, fire frequency, and fire size changes were site specific. A general
pattern was not described. For more information, see Miller .
Tree parameter estimations:
Regression equations to estimate Jeffrey pine diameter, bark thickness, height,
and crown width of Jeffrey pine are available. From Dolph , equations for
estimating inside Jeffrey pine bark diameter and bark thickness are available
for trees less than 81 years old on Sierra Nevada western slopes. Equations for
estimating the height of Jeffrey pine from the Klamath Mountains using
DBH are available from Garman and others . Estimation
equations to compute maximum crown width from DBH for Jeffrey pine in southwestern
Oregon are provided by Paine and Hann .
Snags and decay ecology:
Snag creation, breakage, fall, and decay rates have been studied in several Jeffrey
pine forests from northern California to Baja California Norte. Jeffrey pine snags
did stand for long periods when populations were monitored from 1975 to 1983 in second-growth
Jeffrey pine- and white fir-dominated forests on the Sagehen Creek drainage. Jeffrey pine snags typically fell sooner
than white fir snags, and small-diameter trees fell sooner than large-diameter
trees. Researchers indicated that 75% of the Jeffrey pine snags (excluding the smallest
size class) in the study area would fall after 11 years. Jeffrey pine snags decayed rapidly
from 1978 to 1983. Of 224 Jeffrey pine snags that still had needles, twigs, and more than 20 limbs in 1978, 41%
had no needles, twigs, and fewer than 20 limbs by 1983, and 40% had fallen. Of the new snags that
formed during the same time period, 68% were Jeffrey pine, and 38% of the
Jeffrey pine snags were less than 6 inches (15 cm) in DBH. Jeffrey pine beetles were the
primary cause of mortality [134,135]. For 9 years snags were studied in
Modoc and Lassen National Forests, Lassen Volcanic National
Park, and Blacks Mountain Experimental Forest. The Jeffrey pine snag creation rate
ranged from 17 to 216 new snags/year. Most Jeffrey pine snags (96%) did not decrease in
height over the study period. The average annual fall rate was 6.8% for Jeffrey
pine snags. Small-diameter snags were more likely to fall than larger snags, and Jeffrey pine trees were more likely to fall
than break. A prescribed fire on 1 site increased the Jeffrey pine snag fall rate .
In Jeffrey pine-mixed-conifer forests of the Sierra San Pedro MÃ¡rtir, 52.6% and 23% of snags were Jeffrey pine and white fir,
respectively. Snag DBH averaged 22.8 inches (57.9 cm) for all species and ranged from
1 to 43.8 inches (2.6-111.3 cm). Snag height averaged 43 feet (13 m) and ranged from
6.2 to 95.5 feet (1.9-29.1 m). A majority (85%) of snags were large (>12 inch (30 cm) DBH). Snag density
averaged 3.95/ha, but snag distribution was patchy. Thirty-five percent of plots had no snags, 65% had less than
the average density, and 18% had over 10 snags/ha. Snag abundance
increased following severe drought conditions between 1999 and 2003. The highly
variable snag attributes caused researchers to question management guidelines
with uniform snag targets . For additional
information on decomposition and nutrient cycling in Jeffrey pine forests, see the
in-depth study of burned and unburned Jeffrey pine forests in Little Valley, Nevada, by Stark .
Cultivars, improved and selected materials (and area of origin)
Discovered in 1852 in the Shasta Valley of California by Scottish botanist, John Jeffrey, Jeffrey pine was first classified as a variety of ponderosa pine due to its physical resemblance and the similarity of its geographic range. It is closely related to ponderosa pine, producing wood of equal structure and quality.
Contact your local Natural Resources Conservation Service (formerly Soil Conservation Service) office for more information. Look in the phone book under ”United States Government.” The Natural Resources Conservation Service will be listed under the subheading “Department of Agriculture.”
Relevance to Humans and Ecosystems
Value for rehabilitation of disturbed sites
Jeffrey pine seedlings planted on reclaimed or decommissioned mine sites have been successful, and when a seed source is available, Jeffrey pine may natural colonize mine spoils. For additional information, see Hoover and others , Walker [202,203,204], and Butterfield and Tueller .
Importance to Livestock and Wildlife
American black bears, a variety of small mammals, many bird species, as well as insects, amphibians, and reptiles utilize Jeffrey pine habitats and/or feed on Jeffrey pine seedlings or seeds. Jeffrey pine seed feeders identified in the literature include California quail, northern flickers, American crows, Clark's nutcrackers, western gray squirrels, Douglas's squirrels, California ground squirrels, Heermann's kangaroo rats, deer mice, yellow-pine chipmunks, least chipmunks, Colorado chipmunks, lodgepole chipmunks, and Townsend's chipmunks . In the Little Valley of western Nevada, yellow-pine chipmunks, golden-mantled ground squirrels, and Steller's jays gathered and cached Jeffrey pine seed. Golden-mantled ground squirrels scatter-hoarded Jeffrey pine seed, but often buried seeds too deep for successful germination. American black bears, quail, mule deer, mountain chickadees, nuthatches, and sparrows were common Jeffrey pine seed predators. Yellow-pine chipmunks were, however, the most effective Jeffrey pine seed dispersers. They often transported seeds to favorable germination and establishment sites, and their rapid removal of seeds decreased the chance of immediate predation . If interested in more information on seed dispersal, caching, and on the eventual fate of cached Jeffrey pine seed, see sections on Animal dispersal, Clark's nutcracker dispersal, Seed banking, and Cached seed.
American black bears: There are observations of American black bears feeding on Jeffrey pine seeds and seedlings. Lanner  reports that when Jeffrey pine seeds are available, American black bears "lick up" large quantities. In Little Valley, American black bears fed on the tops of Jeffrey pine seedlings (Goodrich, personal communication in ).
Small mammals: Small mammals often cache and feed on Jeffrey pine seed. On the eastern slope of the Sierra Nevada in Mono and Madera counties, golden-mantled ground squirrels, chipmunks (Tamius spp.), and Douglas's squirrels fed on Jeffrey pine seeds . In the northern Sierra Nevada, 10% of Townsend's chipmunks stomachs had small amounts of Jeffrey pine seed, and 6% of cheek pouches contained Jeffrey pine seed, although woody plant seed was scarce . Jeffrey pine seedlings in south-central Oregon suffered 74.2% mortality over a 3-year period; mortality was primarily from winter feeding by pocket gophers .
Birds: Jeffrey pine provides food and habitat for birds. Cavity-nesting birds often utilize Jeffrey pine. In 3 years of study in eastside forests of Modoc, Lassen, and Shasta counties, 110 active nests were located, and all but 4 were in Jeffrey pine or ponderosa pine. Seventeen nests belonged to hairy woodpeckers, 16 to pygmy nuthatches, 12 to mountain chickadees, and 11 to red-breasted nuthatches. Researchers located Jeffrey pine snags with more than 8 nest holes, although trees with 8 or more nest holes were generally uncommon. Nesting was most common in dead trees with DBH of 16 inches (40 cm) or more, and nests were typically built 3 feet (10 m) or more above ground . Researchers found 561 active cavity nests occupied by 18 species in the Sagehen Creek Field Station. Burned Jeffrey pine-white fir habitats were selected for nesting in significantly greater proportion than by chance based on habitat availability (P<0.05). Most nests were in snags (72%); 19% of nests were in dead tops of live trees; just 2% of nests were in live trees with intact tops. Sixteen of the 18 cavity-nesting species used Jeffrey pine for nesting. All western bluebird, 43% of Lewis's woodpecker, 38% of house wren, and 31% of American kestrel nests were in Jeffrey pine. Cavity-nesting birds foraged more in Jeffrey pine than expected based on availability . There is additional information on Jeffrey pine snags in Snags and decay ecology.
Near the Cuyamaca Reservoir in San Diego County, acorn woodpeckers used many Jeffrey pine trees to store California black oak acorns. Acorns were stashed in cracks or in holes drilled in the bark. The researcher estimated that 13,200 acorns were stored in a single extensively used tree . On the eastern slope of the Sierra Nevada in Mono and Madera counties, the following bird species fed on Jeffrey pine seeds: Williamson's sapsucker, hairy woodpecker, white-headed woodpecker, mountain chickadee, white-breasted nuthatch, Cassin's finch, red crossbill, and pine grosbeak .
Owls: Flammulated and California spotted owls utilize Jeffrey pine habitats. Flammulated owls in California are often found in ponderosa pine and/or Jeffrey pine forests. The flammulated owl breeding range is associated with the presence of Jeffrey pine and/or ponderosa pine . In the Lassen National Forest, California spotted owls utilized mixed red fir, white fir, and Jeffrey pine forests for foraging. In the San Bernardino Mountains, Jeffrey pine trees used by nesting California spotted owls averaged 40 inches (100 cm) DBH, 116 feet (35 m) tall, and 233 years old. Averages came from 8 Jeffrey pine trees .
Clark's nutcracker: Jeffrey pine is an important food source for Clark's nutcracker in the Sierra Nevada. On the eastern slope of the Sierra Nevada in Mono and Madera counties, whitebark pine (Pinus albicaulis) and Jeffrey pine were the Clark's nutcracker's most important and productive food sources. Clark's nutcracker ate seed fresh and from recovered caches. Harvests of Jeffrey pine seed began in early- to mid-September in most years, but started by 1 August in one observation year. Stores of Jeffrey pine seed were made from mid-September through mid-October. Clark's nutcrackers quality-tested seed by rattling the seed against their mandibles to assess seed weight. Seeds were cached in shallow trenches dug and covered by the bill. Seeds from cones that remained on Jeffrey pine trees in the winter and midspring were also utilized by Clark's nutcracker . On the Inyo National Forest, Clark's nutcrackers retrieved more of their caches in the spring and summer than would be expected by trial-and-error seaching. Caches were comprised primarily of Jeffrey pine seeds. Small mammal pilfering may have affected success rates . For more on caches, see Clark's nutcracker dispersal.
Amphibians/reptiles: Pine, mixed-conifer, and conifer-oak forests that often include Jeffrey pine are important habitat for sensitive or threatened snakes and salamanders of southern California including the southern rubber boa, San Diego kingsnake, San Gabriel Mountain salamander, and the yellow-blotched salamander .
Insects: In mixed-conifer old-growth forests on the Teakettle Experimental Forest, cave crickets and pseudoscorpions were found most often or exclusively on Jeffrey pine trees. Jeffrey pine trees had high Simpson diversity, indicating an even distribution of small numbers of insect functional groups. Total abundance of arthropods on Jeffrey pine averaged 98 arthropods/kg of plant material .
Palatability/nutritional value: There was little information available on the palatability and nutrition of Jeffrey pine trees. Jeffrey pine seeds from Washoe County Nevada were 31.5% crude protein, 47.8% crude fat, 8% soluble carbohydrates, and 0.6% crude fiber .
Cover value: Jeffrey pine provides important habitat and likely important cover to several bird and mammal species. Information on use of Jeffrey pine as cover was integrated into Importance to Livestock and Wildlife.
Other uses and values
Jeffrey pine provided a food source and was used to treat pulmonary problems by early western people. The Paiute of Owens Valley and Mono Lake collected Pandora moth larvae from Jeffrey pine forests. Larvae were smoked, cooked, dried, and stored until eventually boiled and eaten at a later date . Beginning in 1890, heptane distilled from Jeffrey pine was sold to treatment pulmonary problems and tuberculosis. Jeffrey pine heptane was also used to develop the octane scale used to rate petroleum used in automobiles (Mirov and Hasbrouck as cited in ).
Wood Products: Jeffrey pine is utilized for lumber. The wood is hard and strong .
Ethnobotanic use. The turpentine obtained from the resin of all pine trees is antiseptic, diuretic, rubefacient and vermifuge. It is a valuable remedy used internally in the treatment of kidney and bladder complaints and is used both internally and as a rub and steam bath in the treatment of rheumatic affections. It is also very beneficial to the respiratory system and so is useful in treating diseases of the mucous membranes and respiratory complaints such as coughs, colds, influenza and externally it is a very beneficial treatment for a variety of skin complaints, wounds, sores, burns, boils etc and is used in the form of liniment plasters, poultices, herbal steam baths and inhalers.
Commercial uses: The primary use for Jeffrey pine is for lumber. The low-grade Jeffrey pine trees are processed into dimensional lumber, as well as other construction products. Some of the other construction products made from high-grade lumber, as a raw material are molding, millwork, cabinets, doors, and windows. It is important to note that for commercial use, no distinction is made between the wood of Jeffrey pine and ponderosa pine.
Pure n-heptane is distilled from Jeffrey Pine resin. It was selected as the zero point on the petrol octane rating scale. Jeffrey Pine resin cannot be used to make turpentine, as n-heptane is explosive when ignited.
Wildlife uses: The Jeffrey pine forests provide wildlife cover for birds, small mammals and big game. Its’ seeds are both disseminated and eaten by insects, birds, and small mammals such as mice, chipmunks, and tree squirrels.
Jeffrey pine, Pinus jeffreyi, also known as Jeffrey's pine, yellow pine and black pine, (Washo: madá:š dewdíʔiš) is a North American pine tree. It is named in honor of its botanist documenter John Jeffrey.
Distribution and habitat
Jeffrey pine occurs from southwest Oregon south through much of California (mainly in the Sierra Nevada), to northern Baja California in Mexico. It is a high-altitude species; in the north of its range, it grows widely at 1,500 to 2,100 m (4,900 to 6,900 ft) altitude, and at 1,800 to 2,900 m (5,900 to 9,500 ft) in the south of its range.
Jeffrey pine is tolerant of serpentine soils and is often dominant in these conditions, even on dry sites at fairly low altitudes. On other soils, it only becomes dominant at higher altitudes where the usually faster-growing ponderosa pine (Pinus ponderosa) does not thrive.
Jeffrey pine is a large coniferous evergreen tree, reaching 25 to 40 m (82 to 131 ft) tall, rarely up to 53 m (174 ft) tall, though smaller when growing at or near tree line. The leaves are needle-like, in bundles of three, stout, glaucous gray-green, 12 to 23 cm (4.7 to 9.1 in) long. The cones are 12 to 24 cm (4.7 to 9.4 in) long, dark purple when immature, ripening pale brown, with thinly woody scales bearing a short, sharp inward-pointing barb. The seeds are 10 to 12 mm (0.39 to 0.47 in) long, with a large (15 to 25 mm (0.59 to 0.98 in)) wing.
The Jeffrey pine may be distinguished from the closely related ponderosa pine by the needles (image at left), which are glaucous, less bright green than those of ponderosa pine, and by the stouter, heavier cones with larger seeds and inward-pointing barbs (see image lower left). Jeffrey pine is also very distinct from ponderosa pine in its resin scent, variously described as reminiscent of vanilla, lemon, pineapple, violets, apple, and, quite commonly, butterscotch; compared to the turpentine or odorless scent of ponderosa pine. This may be tested by breaking a small shoot or some needles, or by sampling the scent of the resin in between the plates of the bark. This difference in scent is related to the very unusual composition of the resin, with the volatile component made up almost entirely of pure n-heptane. Jeffrey pine can be distinguished from ponderosa pine by the smaller scales of bark as compared to the larger plates of more reddish-colored ponderosa bark.
Jeffrey pine wood is similar to ponderosa pine wood, and is used for the same purposes. The exceptional purity of n-heptane distilled from Jeffrey pine resin led to n-heptane being selected as the zero point on the octane rating scale of petrol.
As n-heptane is explosive when ignited, Jeffrey pine resin cannot be used to make turpentine. Before Jeffrey pine was distinguished from ponderosa pine as a distinct species in 1853, resin distillers operating in its range suffered a number of 'inexplicable' explosions during distillation, now known to have been caused by the unwitting use of Jeffrey pine resin.
- Conifer Specialist Group (1998). Pinus jeffreyi. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 5 May 2006.
- Elliot, Daniel Giraud (1904). "A List of Mammals obtained by Edmund Heller from the Coast Region of Northern California and Oregon". Zoological Series no 76 (Field Museum of Natural History) III (11).
- "The Washo Project Online Dictionary". Retrieved 2012-05-27.
- Burns, R.M.; B.H. Honkala (1990). "Pinus Jeffreyi". Silvics of North America. U.S. Department of Agriculture. Agriculture Handbook 654.
- Moore, Gerry; Kershner, Bruce; Craig Tufts; Daniel Mathews; Gil Nelson; Spellenberg, Richard; Thieret, John W.; Terry Purinton; Block, Andrew (2008). National Wildlife Federation Field Guide to Trees of North America. New York: Sterling. p. 86. ISBN 1-4027-3875-7.
- "Jeffrey Pine". enature.com. Archived from the original on 2011-06-14.
- Vizgirdas, Ray S.; Rey-Vizgirdas, Edna M. (2006). Wild Plants of the Sierra Nevada. Reno, Nevada: University of Nevada Press.
- Royal Horticulture Society_Pinus jeffreyi
- Chase, J. Smeaton (1911). Cone-bearing Trees of the California Mountains. Chicago: A. C. McClurg & Co. p. 99. LCCN 11004975. OCLC 3477527. LCC QK495.C75 C4, with illustrations by Carl Eytel - Kurut, Gary F. (2009), "Carl Eytel: Southern California Desert Artist", California State Library Foundation, Bulletin No. 95, pp. 17-20 retrieved Nov. 13, 2011
Names and Taxonomy