Pinus sabiniana (sometimes spelled P. sabineana), with vernacular names including towani pine, foothill pine, gray pine, bull pine, and digger pine, is a pine endemic to California in the United States. Some sources discourage using the name "digger pine," considering it pejorative ("digger" was a slur commonly used to refer to Indigenous Americans in the Great Basin and California).
Description
The Pinus sabiniana tree typically grows to , but can reach feet in height. The needles of the pine are in fascicles (bundles) of three, distinctively pale gray-green, sparse and drooping, and grow to in length. The seed cones are large and heavy, in length and almost as wide as they are long.<ref name="usdaTreat" /> When fresh, they weigh from , rarely over . The male cones grow at the base of shoots on the lower branches.<ref name="usdaTreat"></ref>
Distribution and habitat
Pinus sabiniana grows at elevations between sea level and and is common in the northern and interior portions of the California Floristic Province. It is found throughout the Sierra Nevada and Coast Ranges foothills that ring the Central, San Joaquin and interior valleys; the Transverse and Peninsular Ranges; and Mojave Desert sky islands. Multiple specimens have also been found in Southern Oregon as well. It is adapted to long, hot, dry summers and is found in areas with an unusually wide range of precipitation: from an average of per year at the edge of the Mojave to in parts of the Sierra Nevada. It prefers rocky, well drained soil, but also grows in serpentine soil and heavy, poorly drained clay soils. It commonly occurs in association with Quercus douglasii, and "Oak/Foothill Pine vegetation" (also known as "Oak/Gray Pine vegetation") is used as a description of a type of habitat characteristic within the California chaparral and woodlands ecoregion in California, providing a sparse overstory above a canopy of the oak woodland.
Ecology and uses
Pinus sabiniana needles are the only known food of the caterpillars of the Gelechiid moth Chionodes sabinianus. Fossil evidence suggests that it has only recently become adapted to the Mediterranean climate as its closest relatives are part of the Madrean pine-oak woodlands found at higher elevations in the southwest US and Mexico. Some Native American groups relied heavily on sweet pine nuts for food and are thought to have contributed to the current distribution pattern, including the large gap in distribution in Tulare County. Native Americans also consumed the roots.
Special uses
Protein and fat nutritional value of the seed are similar to Pinus pinea seeds and figured in the local indigenous diet.
Wood uses historically were determined by its particular characteristics, e.g., 0.43 mean specific gravity nearly equal to Douglas-fir (Pseudotsuga menziesii); strength properties similar to ponderosa pine; Kraft pulps high in bursting with tensile strength comparable to some northern conifer pulps; and foothill stands loggable in winter, when higher-altitude species were inaccessible. However, the high amounts of resin and compression wood, the often crooked form, heavy weight, and low stand density, made it expensive otherwise to log, transport and process. Commercial value decreased by the 1960s, to limited use for railroad ties, box "shook", pallet stock, and chips.
It may still offer potential as windbreak shelterbelt plantings.
The main turpentine constituent, heptane, an alkane hydrocarbon, at about 3 percent of needle and twig oil, is unusual in botany; the only other source in nature perhaps being the Pittosporum resiniferum known as "petroleum nut" or kerosene tree.
Taxonomy
Common name
The name digger pine supposedly came from the observation that the Paiute foraged for its seeds by digging around the base of the tree, although it is more likely that the term was first applied to the people; "Digger Indians" was in common use in California literature from the 1800s. The historically more common name digger pine is still in widespread use. The Jepson Manual advises avoiding this name as the authors believe "digger" is pejorative in origin. It is also sometimes thought of as a pinyon pine, though it does not belong to that group.