The term bristlecone pine covers three species of pine tree (family Pinaceae, genus Pinus, subsection Balfourianae). All three species are long-lived and highly resilient to harsh weather and bad soils. One of the three species, Pinus longaeva, is among the longest-lived life forms on Earth. The oldest Pinus longaeva is more than 5,000 years old, making it the oldest known individual of any species.
This standing tree may have died hundreds of years ago. Scientific matching of dead trees' growth rings with living ones has created a 9,000-year-long record.
More Bristlecone trees can be found in our Lynx Habitat. They are located within the exhibit and one outside the east viewing station.
Mystery Grove - Bristlecone Pine
Off the pathway system, deep in the Asian Habitats Collection, grows a conifer grove. Arboretums use accession records to record all new species of plants installed in the property and to research past history and growth of previous installations. The arboretum has no accession records for any of these trees, hence the mystery. Within this grove you will find a group of Bristlecone Pines, healthy and reaching for sunshine. From the facts you will read below, the Bristlecone is the oldest living tree found. Some almost 5,000 years old ! We know that the specimens are not native, so were planted years ago but no more than twenty-five years. It's our goal to keep these trees special and lasting for future generations and to keep the mystery going.
You can request a private viewing of this grove as part of our "Out on a Limb" walking tour. Contact the Zoo for more information
Bristlecone pines are known for attaining great ages. A specimen of Pinus longaeva located in the White Mountains of California is 5,068 years old—the oldest known individual tree in the world—according to measurements by Tom Harlan. The identity of the specimen is being kept secret by Harlan. Another well-known bristlecone pine in the White Mountains is Methuselah which is 4,850 years old. The specific location of Methuselah is also a secret.
The other two species, Pinus balfouriana and Pinus aristata, are also long-lived, though not to the extreme extent of P. longaeva; specimens of both have been measured or estimated to be up to 3,000 years old. The longevity of the trees is believed to be related to the proportion of dead wood to live wood. This high ratio reduces respiration and water loss, thereby extending the life of the tree.
Trees that reproduce by cloning can be considered to be much older than bristlecone pines. A colony of 47,000 quaking aspen trees (nicknamed "Pando"), covering 106 acres in the Fishlake National Forest of the United States, has been estimated to be 80,000 years old, although tree ring samples date individual, above-ground trees at an average of about 130 years.
The bristlecone pine is invaluable to dendroclimatologists, because it provides the longest continual climatically sensitive tree-ring chronologies on Earth. By cross-dating millennia-old bristlecone pine debris, some chronologies reach beyond 9,000 years before present. In addition, ratios of stable carbon isotopes from bristlecone pine tree rings are sensitive to past variations in moisture availability. This information can be used to reconstruct precipitation changes in the past.
The Rocky Mountain population is severely threatened by an introduced fungal disease known as white pine blister rust, and by mountain pine beetles Climate change may also affect the species as temperatures increased 0.5–1 °C (0.90–1.80 °F) over a 30 year period throughout the southern Rocky Mountain range. These changes in climate would mostly affect trees in higher elevations. With these problems, the genetic diversity within the species has become a concern; however, old specimens of bristlecone pine have survived previous warmer periods
Look in the Sensory Garden for our oldest Bristlecone Pine specimen
Bristlecone pines grow in isolated groves just below the tree line, between 5,600 and 11,200 ft (1,700 and 3,400 m) elevation on dolomitic soils. The trees grow in soils that are shallow lithosols, usually derived from dolomite and sometimes limestone, and occasionally sandstone or quartzite soils. Dolomite soils are alkaline, high in calcium and magnesium, and low in phosphorus. Those factors tend to exclude other plant species, allowing bristlecones to thrive.
Because of cold temperatures, dry soils, high winds, and short growing seasons, the trees grow very slowly. Even the tree's needles, which grow in bunches of five, can remain on the tree for forty years, which gives the tree's terminal branches the unique appearance of a long bottle brush.
The bristlecone pine's root system is mostly composed of highly branched, shallow roots, while a few large, branching roots provide structural support. The bristlecone pine is extremely drought tolerant due to its branched shallow root system, its waxy needles, and thick needle cuticles that aid in water retention.