Bristlecone Pines: The Oldest Living Tree

On our recent trip to California, my wife and I drove up to Schulman Grove in the White Mountains to see the ancient bristlecone pines. Specimens of the Great Basin bristlecone pine (Pinus longaeva), are the oldest living trees in the world. These bristlecone pines have needles that grow in bundles of five. The needles are short for a pine, only about one inch long and spread along the branch like a bottle brush. However, these short needles live a long time, lasting up to 43 years. The cones are about three inches long. The growth form is often contorted and gnarled. Old trees have colorful, exposed wood that has lost its bark. Great Basin bristlecone pines grow at elevations over 10,000 feet in the White Mountains of California, and to the east in the mountains of Nevada and Utah. 

In 1953, Edmund Schulman discovered the world's first known 4000-year-old tree in the grove of bristlecone pines now called Schulman Grove. He used an increment borer to get samples of the growth rings of many of the bristlecone pines in the area and discovered one that was over 4700 years old. The oldest known living tree is another bristlecone pine that is over 5000 years old (5060 years old in 2012). It is growing at an undisclosed location, about 12 miles north of Schulman Grove.

Schulman Grove is located 24 miles from Big Pine, California. The road to get there is paved, but steep and winding. There is parking at the Ancient Bristlecone Pine Forest Visitor Center, where you can hike three trails at Schulman Grove. There is no water to be had in lake, stream, spring, or well, which tells you something about the arid nature of the White Mountains, and should suggest something about the nature of the bathroom facilities located near the Visitor Center. I hiked around the mile long Discovery Trail loop to get the photos shown here.

Tree-ring dating
It's easy to determine the age of a tree by counting the annual growth rings after it has been cut down. A less destructive way is to use an increment borer. This device is a long hollow drill bit that can extract a thin cross section of a tree, which enables you to count the tree rings. Also, since the rings are wider in wet years, you can determine variable weather patterns throughout the history of a tree. Furthermore, this variability forms patterns that researchers can recognize in different core samples. By comparing cores from living trees with cores from dead trees and wood fragments, researchers can extend their knowledge of weather patterns back for thousands of years. We now have a continuous record of bristlecone pine tree rings going back over 11,000 years. Also, tree rings in the wood at archaeological sites enable scientists to determine the age of the wood.

Since the tree rings provide an accurate count of the years, this research has enabled scientists to calibrate the readings from radiocarbon dating, giving archaeologists all over the world more accurate data on the age of artifacts.

Gray Pine

I was at the Portland Chapter meeting of the Native Plant Society recently and someone there told me that the gray pine (Pinus sabiniana) was an Oregon native. This was news to me. It’s not listed in Trees to Know in Oregon, from the Oregon State University Extension Service. Also, Ronald Lanner writes in Conifers of California that gray pine is “…a native to California alone – without any Nevada or Oregon outliers.” (p. 71) He goes on to quote David Douglas on the discovery of the gray pine: “I have added a most interesting species to the genus Pinus, P. sabinii, one which I had first discovered in 1826, and lost, together with the rough notes, in crossing a rapid stream.” However, David Douglas was not in California in 1826. He was in the Umpqua Valley area of Oregon in search of sugar pine, where he must have also seen some gray pine. The “rapid stream” he crossed was the Santiam River.

Frank Callahan documents the discovery of the gray pine in Oregon. He reports that a railroad survey in 1855 recorded them growing in Jackson County between Gold Hill and Central Point. In 1945, Oliver Matthews provided the first scientific documentation of Pinus sabiniana in Oregon after collecting specimens near Gold Hill. Callahan notes numerous specimens that he has located in the Medford area.  (See Frank Callahan, “Discovering Gray Pine (Pinus sabiniana) in Oregon,” Kalmiopsis Volume 16, 2009.

The gray pine is a distinctive pine with long, gray-green needles. Its most distinctive feature is the size of its large, heavy cones. They are usually visible it the top branches of the tree, where they remain for several years after they mature. The cones have the largest seeds of any conifer in the Pacific Northwest. The nutritional seeds were harvested by Native Americans, although too few trees grew in Oregon for them to be an important food source. Since the seeds are too large to be dispersed far from the tree, the gray pine relies on birds to disperse the seeds. Gray pine seeds are a favorite food of the Steller’s jay and scrub jay, which store seeds in the ground to eat later. Since the jays never recover all the seeds, they also plant the next generation of gray pines.

For more information, see Northwest Conifers.

Focus on Pines

Western White Pine

Pine are the most common conifer in the world, spreading across the land masses of the Northern Hemisphere, including much of North America, Europe, and Asia. The genus of the pines, Pinus, includes over 100 species, more than any other conifer genus. (Aljos Farjon lists 113 species of pine in A Handbook of the World’s Conifers.) Pinus is classical Latin for the Mediterranean stone pine.

Pines have an ancient origin, appearing 130 million years ago. They are older than the firs, spruces, larches, hemlocks, and Douglas firs. All these conifers branched off from ancient pines. Some pine trees are ancient. They can live to be thousands of years old. The oldest living tree is a bristlecone pine that is over 5000 years old, growing in the White Mountains of California.

Northwest Pines

Eight species of pine grow in the Pacific Northwest. Pines don't compete as well in the climate west of the Cascades summit, where forests are dark, damp, and dense. You will find them high in the mountains east of the Cascades summit. Pines are not shade-tolerant and compete best in drier areas where the forests are more open. In a favorable environment many Northwest pines grow to an impressive size, especially sugar pine. Pines can also thrive in poor soils where other trees cannot compete. In extreme environments like cold, wind-swept ridges and the windy Pacific Coast, the pines are often small and contorted. 

Ponderosa Pine

Many pines have an interesting relationship with fire. Since they are not shade-tolerant, they often depend on fire to clear the forest of competing trees before the pine seedlings can sprout and grow. Some species depend on frequent fires. Ponderosa pine depends on low-intensity fires that burn competing species every few years. The thick bark on the ponderosa protects it from the fire, but the fire burns the competing firs. Other pines depend on hotter fires that consume the forest. The cones of knobcone pine and some lodgepole pine remain closed on the tree until they are heated during a fire. After the fire, the cones open and drop their seeds, which germinate and grow to become the next generation of pines.

Whitebark Pine

Other pines take advantage of extreme environments or mutually beneficial relationships with animals. Whitebark pine has adapted to the extreme cold and snowy environment near the timberline. It has also developed a close relationship with the Clark’s nutcracker. This pine holds its seeds in closed cones, waiting not for a fire, but for a Clark’s nutcracker to come and pry out the large, edible seeds. The nutcrackers typically fly off and bury the seeds, which they dig up and eat during the winter. But the seeds that they forget about can germinate and sprout new little whitebark pines. This adaptation of producing large edible seeds is a common tactic used by several species of pines, often called “stone pines.” Birds are not the only animals to benefit. Pine seeds are a traditional food for people, too. If you have extra money to burn, you can buy them today in nearly any grocery, where they are sold as “pine nuts.”

Although ponderosa pine thrives in the dry areas east of the Cascades, it is also native to the Willamette Valley, where it has adapted to the wet environment, and competes well with Douglas fir. Lodgepole pine mostly grows in the Cascades and Rocky Mountains, but it also grows along the Pacific Coast, where it is called “shore pine.” It has adapted to the wet, salty environment along the beach and in nearby bogs.

Uses

Limber Pine Cultivar
"Vanderwolf's Pyramid" 

Pines arean important timber resource throughout the world. They are grown in plantations in the south of the U. S. and various locations around the world, including New Zealand and Brazil. The wood is used for construction, woodworking, window frames, and furniture. Pine is a favorite wood for paneling. Pines are a primary source of pulp for paper making. They are also a source for making turpentine.

Pines are widely planted as ornamentals, a tribute to their beauty, but perhaps also because they are often slow-growing. Stately ponderosa pine is a favorite. Its golden bark adorns parks throughout the West. Pines seem to lend themselves to the development of a wide variety of cultivars of different size, shape, and color. The Encyclopedia of Conifers includes 360 pages of pine cultivars.

Identification of Northwest Pines

It’s easy to distinguish pines from other conifers. Pine needles typically grow in bundles of two, three, or five. Unlike the thin scales on hemlock and spruce cones, pine cones have thick, woody scales. The cones are the largest you will find in the Northwest. You can usually identify a pine species by the number of needles in each bundle or the shape and size of the cones.

Lodgepole Pine – Pinus contorta

Needles: 2 per bundle. Cones: 2” long, egg shaped.

Western white pine – Pinus monticola

Needles: 5 per bundle, 2-4” long. Cones: 6-10” long, curved.

Whitebark pine – Pinus albicaulis

Needles: 5 per bundle, 2-3” long. Cones: 2-3” long, closed when mature.

Ponderosa pine – Pinus ponderosa

Needles: 3 per bundle, 5-10” long. Cones: 3-6” long, egg shaped.

Jeffrey pine – Pinus jeffreyi

Needles: 3 per bundle, 5-10” long. Cones: 6-10” long. SW Oregon.

Knobcone pine – Pinus attenuata

Needles: 3 per bundle, 3-6” long. Cones: 3-6” long. SW Oregon.

Sugar pine – Pinus lambertiana

Needles: 5 per bundle, 2-4” long. Cones: Large, 10-20” long. SW Oregon.

Limber pine – Pinus flexilis

Needles: 5 per bundle, 2-3” long. Cones: 3-7” long, open when mature. This pine is rare in the Northwest, growing only in the Wallowa Mountains.

References

The Gymnosperm Database – Pinus

http://www.conifers.org/pi/Pinus.php

The Encyclopedia of Conifers by Aris G. Auders and Derek P. Spicer, Vol. 2

A Handbook of the World’s Conifers by Aljos Farjon, Vol 2

Conifers of the World by James E. Eckenwalder

The Wood Database – Pine Wood

http://www.wood-database.com/wood-articles/pine-wood-an-overall-guide/