Coulter pine

Coulter pine (Pinus coulteri), or big-cone pine, is a native of the coastal mountains of Southern California in the United States and northern Baja California in Mexico. Isolated groves are found as far north as Clearlake, California on the flanks of Mt. Konocti and Black Diamond Mines Regional Preserve. It is named after Thomas Coulter, an Irish botanist and physician. The Coulter pine produces some of the heaviest cones of any pine tree, up to 5 kg and among conifers is exceeded only by the cones of Araucaria bidwillii.

Although it has a limited range in the wild, the Coulter pine is a popular ornamental tree and is grown in many countries.

Description
Pinus coulteri is a substantial coniferous evergreen tree in the genus Pinus. The size ranges from 10 – tall, and a trunk diameter up to 1 m. The trunk is vertical and branches horizontal to upcurved. The leaves are needle-like, in bundles of three, glaucous gray-green, 15 – long and stout, 2 mm thick.

The outstanding characteristic of this tree is the large, spiny cones which are 20 – long (occasionally as much as twenty inches (51 centimeters) length has been observed), 23 centimeters (nine inches) in width, and weigh 2 – when fresh. Each segment, or "scale", of the cone is tipped with a talon-like hook. Coulter pines produce the largest cones of any pine tree species and people are advised to wear hardhats when working in Coulter pine groves, although the slender cones of the sugar pine are longer. The large size of the cones, combined with the claw-like scales, has earned them the nickname "widowmakers" among locals.

Ecology
The Coulter pine is closely related to the foothill pine, Pinus sabiniana. It is more distantly related to Jeffrey pine with which it shares habitats, and the ponderosa pine. Coulter pines tend to grow in drier environments than ponderosa and Jeffery pines.

This erect, medium-sized pine prefers south-facing slopes between 200 – elevation, and tolerates dry rocky soil. Pinus coulteri most often appears in mixed forests. The Coulter pine occurs in a number of forest plant associations; for example, at higher elevations forestation of the San Jacinto Mountains Coulter Pine is co-dominant with the California black oak. Woodpeckers often forage on the species, and peel the bark to access insects underneath.

Uses
Wildlife, especially squirrels, gather the large seeds. They were also once eaten by Native Americans.

The wood is weak and soft, so that the species is little used other than for firewood.

Pinus coulteri is cultivated as an ornamental tree, planted in parks and large gardens, and drought tolerant landscaping. The Coulter pine has gained the Royal Horticultural Society's Award of Garden Merit.