Leonard and I just returned from a week exploring Great Basin National Park and other historical, geological and botanical sites along Nevada Highway 50. For me, one of the highlights of the trip was hiking to the Great Basin Bristlecone Grove at about 11,000 feet on Mount Wheeler in the National Park.
Great Basin bristlecone (Pinus longaeva) is an exceedingly slow-growing tree found in subalpine coniferous forests and the desert mountains of the Great Basin in California, Nevada and Utah between 8,000 and 11,000 feet. Uncommon and vulnerable, this species grows at high elevations where few plants can survive the harsh winds, a short growing season, freezing temperatures and thin, nutrient-poor soils.
Great Basin bristlecones are considered the oldest, non-clonal living trees on earth. They can live 3,000 to 4,000 years. A tree on Wheeler Mountain, now dead, was dated at around 5,000 years of age.
This short, stocky, gnarled and contorted tree usually has multiple stems. Crowns are sparse to absent on individual stems. The reddish brown bark is ridged and shallowly furrowed. Often the bark is scoured off on the windward side of the tree. Very old Great Basin bristlecones often have only a narrow strip of living tissue connecting the roots to a couple living branches. Dead trees can remain standing for hundreds of years.
The needles (leaves) occur in bundles of five. The bundles are tightly arranged on the stems bottlebrush style. Great Basin bristlecone needles are dark green, stiff and somewhat curved with white stomatal lines on the inner surface. Scattered resin droplets dot the needles, which can persist on the branches for 40 years or more.
The pendant Great Basin bristlecone seed cones have short stalks and are often coated in resin. Originally purplish to aid in heat absorption, the seed cones mature to a reddish brown in two years. The cone scale tips are thick and have slender, persistent, claw-like prickles. Once mature, the cones immediately drop their seeds to spread in the wind. Great Basin bristlecones also have a relationship with Clark’s nutcrackers. The birds cache the seeds and many eventually germinate. Pollen cones are a dark orange-red.
Great Basin bristlecone wood is dense and resinous. The resin protects the tree from insects and fungi. Large amounts of resin also make bristlecones extremely vulnerable to fire. However, fires are rare amid the sparse groves at the high altitudes near treeline where they grow. The tree is of no commercial value, but its aesthetic beauty is invaluable.
There are two other “bristlecone” species, one in the Rockies and one in the Klamath Mountains. . . . two more additions to my “quest” list.