Bishop pines (Pinus muricata) endure conditions unfavorable to the growth of other pine species. They grow on low swampy hills, moist flats or rock hills, always near the ocean, in California, Baja Mexico and the Channel Islands. Depending on their environment, bishop pines can assume different growth forms, from strange, twisted shapes where they are tortured by Pacific gales to beautifully symmetrical trees with drooping boughs in sheltered areas. These bishop pines, growing along the Bayview Trail in Point Reyes National Seashore (California), had their lower boughs whipped away and beaten back by strong winds and salt spray.
Bishop pine bark is deeply furrowed and rough with dark purplish brown scales. The deep yellow foliage is arranged in dense, crowded clusters on the branch extremities. The needles occur two per bundle and fall from branches in their second or third summers.
The cones of bishop pines are arranged in circles of two to seven cones on the trunk and branches. They persist indefinitely on the tree. As can be seen in one picture, slow-growing lichen is beginning to cover the cones. The russet-brown cones with prickly scales mature in August of their second year. The cones turn downward and develop more strongly on the outer side making them seem one-sided. Many cones open and release their seeds in September after maturation while others remain closed for 15 to 25 years or more. Bishop pine seeds are black or very dark brown and have a rough surface.
The cones on other pines with persistent cones become embedded in the bark. The stems of bishop pine cones break and the cone is held lightly by the living bark and slowly drawn or forced from the wood by each year’s new growth pushing against the base of the cone.
Bishop pines live from about 150 to 200 years, relatively short-lived. The wood is heavy and hard, yet weak and coarse-grained. The light brown hardwood and nearly white sapwood is resinous and knotty with no commercial value.
This species was first collected and described by Thomas Coulter, an Irish biologist, near Mission San Luis Obispo, named for Saint Louis, Bishop of Tolosa (Toulouse), giving it the common name bishop pine. Others suggest that the name arose because the scale tips thicken at the tip like a bishop’s hat. If you do not like either derivation story, pricklecone pine is another colloquial name for Pinus muricata.
At one point along the trail there was a large grove of dead bishop pines with dark cones still clinging to the old, greying bark. In the fading evening light it reminded me of a ghost forest. Loved it!