Jeffrey Pine | Lot of 30 Tree Seedlings

About Jeffrey Pine

From the U.S. Forest Service:

"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 200 feet (60 m) tall, 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. 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).

Needles are 3 to 11 inches (8-28 cm) long and most often in bundles of 3, but bundles of 2 are possible. Needles are retained for 2 to 10 years. 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. 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. Seed weight averages 123 mg.

Short growing seasons, drought, and cold are tolerated by Jeffrey pine. Throughout the Jeffrey pine range, average January temperatures range from 9 to 36 °F (-13 to 2 °C). Day and nighttime temperatures in July may differ by 47 °F (26 °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.

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."