subgenus Strobus (Lemmon), section Parrya (Mayr), subsection Balfourianae (Engelmann).
Pinus balfouriana, first described in1853 by Robert Kaye Greville (1794–1866) and John Hutton Balfour (1808–1884) ex Johan Andreas Murray (1740–1791), is commonly known as Foxtail pine. The species name honors John Balfour, director of the Royal Botanical Garden at Edinburgh, who described it using the name given by the collector, John Jeffrey.
Ethnobotany. There is little to no evidence of use by indigenous people. Moreover, it has never achieved popularity in horticulture, and is quite rarely seen in botanical gardens. Its principal value to humans is thus aesthetic; the alpine groves of this ancient tree, juxtaposing its brick-red bark and vivid green foliage against blue skies and the white Sierra granite, are exceptionally beautiful even in comparison with other timberline forests
Description. Foxtail pine is an evergreen coniferous species of tree that grows to mature heights of 70 feet (22 m) with an erect or leaning trunk up to 8.5 feet (2.6 m) in diameter, measured at breast height. The tree’s crown is broadly conical to irregular.
- Bark is gray to salmon or cinnamon in color, platy or irregularly deep-fissured or with irregular blocky plates.
- Branches grow contorted, ascending to descending.
- Twigs are red-brown in color, aging gray to drab yellow-gray, glabrous or puberulent, young branches resembling long bottle brushes because of persistent leaves.
- Buds ovoid-acuminate in shape, resinous, red-brown in color, measuring 0.32 to 0.4 inch (0.8 – 1 cm).
- upcurved Leaves (needles) grow in bundles of 5 per fascicle and persist 10 to 30 years on the tree. They measure 0.6 to 1.6 inches (1.5 – 4 cm) long and 0.04 to 0.56 inch (1 – 1.4 mm) wide, mostly connivent. Their color is deep blue- to deep yellow-green, abaxial surface without median groove but usually with 2 sub-epidermal, but evident resin bands, adaxial surfaces conspicuously whitened by stomates, margins mostly entire to blunt, apex is broadly acute to acuminate. Needle sheath measures 0.2 to 0.4 inch 0.5-1cm long, forming a rosette soon after needles push, then shed early.
- Pollen cones are ellipsoid shaped, red in color, and measure 0.24 to 0.4 inch (6 – 10 mm) long.
- Seed cones mature 2 years after pollination, then shed seeds and fall from the tree soon thereafter. Their shape is described as spreading, symmetric, lance-cylindric with conic base before opening; and broadly lance-ovoid or ovoid to cylindric or ovoid-cylindric when open. Cones measure 2.4 to 3.6 inches (6 – 9) cm long, colored purple when young, aging red-brown, nearly sessile along the branch.
- Cone scales, apophyses are much thickened, rounded, larger toward cone base. Umbos central, usually depressed; prickles either absent or weak, to 0.04 inch (1 mm) long, cone resin exude with amber color.
- Seeds are ellipsoid to narrowly obovoid shaped, colored pale brown, mottled with deep red, with a 0.4 inch (10 mm) body. Attached wing is 0.4to 0.48 inch (10-12 mm) long.
“Pinus balfouriana is the true “foxtail pine.” In leaf character it is hardly, if at all, distinguishable from P. longaeva, but its strongly conic-based cones with distinctly shorter-prickled, sunken-centered umbos at once distinguish it from that species”
Distribution. This species is native to USA — California, growing at elevations of 5,000 to 6,000 (1,525 to 1,830 m) above sea, where it grows in open to closed-canopy pure to mixed stands level. Hardy to Zone 5 — cold hardiness limit between -20° and -10°F (-28.8°C and -23.3°C).
One consequence of the open stand structure and barren substrates is that these stands generally do not carry fire. The principal causes of tree death appear to be lightning, avalanche and rockfall. Most large trees show evidence of at least one lightning strike, and they commonly retain a strip-bark growth habit as a legacy of this misfortune. Sometimes the lightning strike ignites the tree, and the tree may be consumed if the fire is not quenched. Regeneration is common in avalanche tracks, where saplings may show evidence of repeated breakage by avalanche. The tree often grows on steep slopes beneath mountain precipices, so it is also common to see trees that have been scarred or broken by rockfall. Occasionally a tree shows scarring due to woodpecker activity, but in general, evidence of both insect and fungal attack is rare, and these are probably minor causes of mortality.
Attributed from: R. Kral, Pinus. Flora of North America Editorial Committee (editors.); Flora of North America North of Mexico, Vol. 2. ©1993, Oxford University Press.