December Tree of the Month: Torrey Pine
By David Gress
The Torrey Pine is thought to be the rarest pine species in North America. It is endemic only to two small areas, both in California: in the Torrey Pines State Natural Preserve located at Del Mar in San Diego County; and, on the eastern end of Santa Rosa Island, just off the coast of Santa Barbara.
Unfortunately, it is now considered a critically endangered species, with its total wild population having declined from 9,000 trees in 1970s to currently less than 4,500 trees. Fortunately, it has been cultivated by nurserymen since the late 1800s and has subsequently been planted outside its two natural areas, so it is not in danger of going extinct at this time.
Interestingly, Torrey Pines in the wild will develop into shapes and sizes that are dramatically different from those that are cultivated. These morphological differences are due to the often drastically varied soil and weather conditions in the locations where they grow naturally and where they have been planted.
Native Torrey Pine stands are found in coastal sage-scrub plant communities, where they suffer from nutrient-poor, dry, sandy soil - and must bear the effects of salt-sprayed winds that blow directly onshore from the Pacific Ocean. These harsh conditions result in wild trees having slow growth, with wind-whipped, stunted, and often contorted forms of both trunks and branches, and a maximum height of only 20 to 50 feet.
Not surprisingly, a Torrey Pine that is cultivated from seed and then given the lifetime benefits of deep rich soil, additional irrigation, and wind protection, is much faster-growing and will develop a straight trunk, widely spaced branches, and an open symmetrical crown that spreads widely at the top. At maturity, a cultivated tree can dominate the landscape with an impressive height of over 100 feet, branch spread of over 60 feet, and a trunk diameter exceeding 8 feet. This tree certainly needs to be planted in a location that provides it with room to grow!
In addition to its growth habit, Torrey Pine is identified by its long needles and its cones. The green to gray-green needles develop in fascicles (bundles) of 5 needles. Individual needles are 8- to 12-inches long that will stay on the tree for up to 3 years. These needles are considered the stiffest and thickest of any pine in North American.
Torrey Pine is monecious, meaning that female cones and male cones appear on the same tree. The cones, called strobili, emerge in January and February. The 1-inch-long pollen (male) cones develop in catkin-like clusters at the ends of twigs and produce copious amounts of yellow pollen that is dispersed by the wind.
After pollination, the female seed cones develop on elongated stalks along the branches, mature slowly over 3 years until they are solid and heavy and 4- to 6- inches long and 4- to 5-inches wide, and ultimately bear two hard dark-brown seeds at the base of each cone scale. When young, seed cones are yellow; when fully mature, they turn a chocolate brown, gradually spread open their scales, and begin to release their seeds; mature seed cones can persist on the tree for over 5 years.
The obovoid-shaped seeds are ½- to 1-inch long with a ½-inch long papery wing. The seeds are dispersed primarily by scrub jays and small mammals. The seeds hold edible nuts (often called “pine nuts”) that were a highly nutritious and important food source for our local indigenous native peoples, the Kumeyaay and the Chumash.
The bark develops dark-gray plates that flake off to reveal a red-brown color underneath. On old trees, the bark will become furrowed with irregular, elongate, flat, sometimes scaly ridges.
The botanical name for Torrey Pine is Pinus torreyana. The genus, Pinus, is Latin for “pines”; the specific epithet, torreyanna, honors Dr. John Torrey (1796 - 1873), an American botanist. Other common names for the Torrey Pine include “Soledad Pine”, “Lone Pine”, and “Del Mar Pine”.
Some older reference sources have listed the Torrey Pine populations in San Diego County and on Santa Rosa Island as separate subspecies. However, recent genetic analysis has found that both populations have identical DNA. This discovery has been noted as support for the concept of the spreading of global tectonic plates - bolstering the idea that the two areas where Torrey Pines are endemic were once geographically adjacent to one another, but have been forced apart over the millennia by the movement of the Pacific Plate (where the Santa Rosa stand is found) north and away from the North American plate (where the San Diego County stand is found).
Several Torrey Pines have been found to be more than 200 years old. The largest known specimen stands right in the heart of our neighboring community of Carpinteria. This remarkable tree is known as the “Wardholme Torrey Pine” (named after the original landowner, Judge Thomas Ward) and was the first designated historical landmark in Carpinteria. It was planted in 1888 as a seedling collected on Santa Rosa Island. It now stands over 125 feet tall, with a spread of 130 feet and a trunk circumference of nearly 25 feet! It has sustained storm damage in recent years, but it is still handsome - and well worth a visit to see it in Carpinteria.
Torrey Pine grows best in full sun with well-drained sandy loam soil. It is drought-tolerant and, when established, can survive on our normal rainfall in areas blessed with spring and summer fog. Understandably, it will grow much faster, larger, and denser with supplemental irrigation. Torrey Pine is cold hardy to between 10° and 20°F. It is relatively pest-free in cultivation; however, in the wild, its needles may be eaten by moth caterpillars and can be afflicted with branch-mutating “witches’ broom” growth (a small mass of overgrown twigs).
Like most pines, its wood is soft and coarsely grained. It has been considered an excellent tree to grow for lumber, but a shortage of available seed has been a problem for large scale commercial plantings.
Torrey Pine provides good soil stabilization and screening on coastal bluffs and hillsides. It makes a picturesque large tree for parks and large-scale landscapes.
Mature examples of Torrey Pine can be seen on the west hillside of Oak Park (planted by Dr. Doremus in 1910); specimens of varying ages stand in the Santa Barbara Cemetery; one in Shoreline Park; several on Cima Linda Lane; some are intermingled with other trees on the north side of Modoc Road between Palermo Drive and Calle De Los Amigos; there is a row of 11 trees, which were planted in 1994, as a screen along the south side of the Tajiguas Landfill west of Goleta - unfortunately, these had their bottom foliage scorched during the recent Alisal Fire, though they should survive.
Tree-of-the-Month articles are sponsored by Santa Barbara Beautiful, whose many missions include the increase of public awareness and appreciation of Santa Barbara’s many outstanding trees and, in a long-time partnership with the City Parks & Recreation Department, the funding and planting of trees along the City’s streets.
Those who wish to honor a special someone can do so with an attractive commemorative marker that will be installed at the base of an existing street tree in the City of Santa Barbara. Because Santa Barbara Beautiful has participated in the planting to date of over 13,000 street trees, there are plenty of trees from which to choose! Application forms are available on the Santa Barbara Beautiful website, www.sbbeautiful.org.
Article and Photos by David Gress