Pinus jeffreyi

jeffrey pine

Pinaceae

The Basics

Taxonomy: Kingdom - Plantae (plants). Subkingdom - Tracheobionta (vascular plants). Superdivision - Spermatophyta (seed plants). Division - Coniferophyta (conifers). Class - Pinopsida. Order - Pinales. Family - Pinaceae (pine) Genus - Pinus L. (pine). Species - Pinus jeffreyi Balf. (jeffrey pine).

Ecology: Jeffrey pine is a large, slow-growing, long-lived conifer. 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 60 m tall, and diameters of up to 2.5 m are reported. Crowns are rounded or long and symmetrical. The Jeffrey pine trunk is normally straight with thick, large plates of bark separated by deep furrows. Needles are 8-28 cm long and most often in bundles of 3, but bundles of 2 are possible.

Identification

Jeffery pine has blue-green, twisted needles, 7-9 in. long. Grows from 40-90 ft. with a pyramidal, open crown. Old trees are devoid of branches for more than 1/2 of their height. Cinnamon-brown to yellow-orange, flaky bark. Cones are 6-9 in. long. Large tree with straight axis and open, conical crown of spreading branches and with large cones. Both bark and twigs give off odor of lemon or vanilla when crushed.

The odor of crushed twigs defies exact description. The scent has been likened not only to lemons and vanilla, but also to violets, pineapples, and apples.

Threats

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. 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 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.

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, and/or seed-caching animals.

Many pathogens and insects infect Jeffrey pine trees, but rarely is Jeffrey pine mortality attributed entirely to a single infection. Often harsh growing conditions co-occur with disease and insect outbreaks. Needle cast was the most common pathogen, and Jeffrey pine beetle the most common insect. 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.

Reproduction

Seed production - Jeffrey pines are monoecious...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. 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... Cones are wind pollinated.

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 1.06 m to 27 m. Dispersal distances reported from seed caching studies range from 2.6 m to 62.9 m.

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... 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.

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.

Species Distribution

Citation

USDA Plant Database
USDA, NRCS. 2016. The PLANTS Database (http://plants.usda.gov, 4 February 2016). National Plant Data Team, Greensboro, NC 27401-4901 USA.

Flora of North America
Flora of North America Editorial Committee, eds.  1993+.  Flora of North America North of Mexico.  19+ vols.  New York and Oxford.

Silvics of North America
Burns, R.M., and B.H. Honkala. 1990. Silvics of North America (Volume 1: Conifers). USDA Forest Service Agricultural Handbook 654.

Intermountain Herbarium
Consortium of Intermountain Herbaria. 2016. http//:intermountainbiota.org/portal/index.php. Accessed on February 04.

Jepson Manual
The Jepson Manual: Vascular Plants of California. B.G. Baldwin, D.H. Goldman, D.J. Keil, R. Patterson, T.J. Rosatti, and D.H. Wilken [editors]. 2012. 2nd edition, thoroughly revised and expanded. University of California Press, Berkeley, CA. $131.95, hardcover; 1600 pages. ISBN-13: 978-0520253124.

USGS Plant Species Range Maps
Critchfield, W.B., and Little, E.L., Jr., 1966, Geographic distribution of the pines of the world: U.S. Department of Agriculture Miscellaneous Publication 991, p. 1-97.
Little, E.L., Jr., 1971-1978, Atlas of United States trees, volume 1,3,13,17, conifers and important hardwoods: U.S. Department of Agriculture Miscellaneous Publications.