Bristlecone pine | |
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A Great Basin bristlecone pine grove | |
The eponymous bristles | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Gymnospermae |
Division: | Pinophyta |
Class: | Pinopsida |
Order: | Pinales |
Family: | Pinaceae |
Genus: | Pinus |
Subgenus: | P. subg. Strobus |
Section: | P. sect. Parrya |
Subsection: | P. subsect. Balfourianae |
Species | |
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 of this species is more than 4,800 years old, [1] making it the oldest known individual of any species. Many scientists are curious as to why this tree is able to live so long. In one study, they discovered that Pinus longaeva has higher levels of telomerase activity, which further slows or prevents the attrition rate of telomeres. [2] This potentially contributes to the extended life of the bristlecone pine.
Despite their potential age and low reproductive rate, bristlecone pines, particularly Pinus longaeva, are usually a first-succession species, tending to occupy new open ground. [3] They generally compete poorly in less-than-harsh environments, making them hard to cultivate. [3] In gardens, they succumb quickly to root rot. [4] They do very well, however, where most other plants cannot even grow, such as in rocky dolomitic soils in areas with virtually no rainfall. [3]
Bristlecone pines grow in scattered subalpine groves at high altitude in arid regions of the Western United States. Bristlecones, along with all related species in class Pinopsida, are cone-bearing seed plants commonly known as conifers; the name comes from the prickles on the female cones. [5]
There are three closely related species of bristlecone pines:
At least some of the three species can hybridize in cultivation, but the ranges of wild populations do not overlap. The Colorado River and Green River produce a 160-mile (260 km) gap between the ranges of P. longaeva and P. aristata and the northern Owens Valley provides a 20-mile (30 km) gap between the ranges of P. longaeva and P. balfouriana. [8]
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. [5] The trees grow in soils that are shallow lithosols, usually derived from dolomite and sometimes limestone, and occasionally sandstone or quartzite soils. Dolomitic soils are alkaline, high in calcium and magnesium, and low in phosphorus. Those factors tend to exclude other plant species, allowing bristlecones to thrive. [9] 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. [8]
The wood is very dense and resinous, and thus resistant to invasion by insects, fungi, and other potential pests. The tree's longevity is due in part to the wood's extreme durability. While other species of trees that grow nearby suffer rot, bare bristlecone pines can endure, even after death, often still standing on their roots, for many centuries. Exposed wood on living and dead trees does not rot, but rather erodes like stone due to wind, rain, and freezing, which creates unusual forms and shapes.
The bristlecone pine has an intrinsically low rate of reproduction and regeneration, and it is thought that under present climatic and environmental conditions the rate of regeneration may be insufficient to sustain its population. [10] The species are on the International Union for Conservation of Nature (IUCN) red list. [10] The species are labeled under Least Concern (LC), the justification for this being that no subpopulations for Great Basin bristlecone pines are decreasing. Subpopulations seem to be increasing or remaining stable. [10] Many bristlecone pine habitats have been protected, including the Inyo National Forest's Ancient Bristlecone Pine Forest in the White Mountains of California and the Great Basin National Park in Nevada, [11] [12] where cutting or gathering wood is prohibited. [11]
The green pine needles give the twisted branches a bottle-brush appearance. The needles of the tree surround the branch to an extent of about one foot near the tip of the limb. [13] The name bristlecone pine refers to the dark purple female cones that bear incurved prickles on their surface. [5] [12] The dark color of these cones helps to absorb heat. After maturity, which takes about two years, the cones will become brown in color. [13] These ancient trees have a gnarled and stunted appearance, especially those found at high altitudes, [8] and have reddish-brown bark with deep fissures. [14] As the tree ages, much of its vascular cambium layer may die. In very old specimens, often only a narrow strip of living tissue connects the roots to a handful of live branches. Even though the trees' needles may age, they still remain functional in regulating water and by their ability to photosynthesize. [8]
Bristlecone pines are known for attaining great ages. The oldest bristlecone pine in the White Mountains is Methuselah, which has a verified age of 4,856 years. It is located in the White Mountains of Inyo County in Eastern California. However, the specific location of Methuselah is a closely guarded secret. [15]
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. [16] 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. [10]
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 (43 ha) in the Fishlake National Forest in Utah, 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. [17] [18]
Bristlecone pines are invaluable to dendroclimatologists, because they provide 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. [8] 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. [19]
The Rocky Mountain population is severely threatened by an introduced fungal disease known as white pine blister rust, and by mountain pine beetles. [20] 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; [21] old specimens of bristlecone pine, however, have survived previous warmer periods.
A pine is any conifer tree or shrub in the genus Pinus of the family Pinaceae. Pinus is the sole genus in the subfamily Pinoideae.
The Douglas fir is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are three varieties: coast Douglas-fir, Rocky Mountain Douglas-fir and Mexican Douglas-fir.
Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta, also known as Coniferophyta or Coniferae. The division contains a single extant class, Pinopsida. All extant conifers are perennial woody plants with secondary growth. The great majority are trees, though a few are shrubs. Examples include cedars, Douglas-firs, cypresses, firs, junipers, kauri, larches, pines, hemlocks, redwoods, spruces, and yews. As of 2002, Pinophyta contained seven families, 60 to 65 genera, and more than 600 living species.
Pinus albicaulis, known by the common names whitebark pine, white bark pine, white pine, pitch pine, scrub pine, and creeping pine, is a conifer tree native to the mountains of the western United States and Canada, specifically subalpine areas of the Sierra Nevada, Cascade Range, Pacific Coast Ranges, Rocky Mountains, and Ruby Mountains. It shares the common name "creeping pine" with several other plants.
Pinus balfouriana, the foxtail pine, is a rare high-elevation pine that is endemic to California, United States. It is closely related to the Great Basin and Rocky Mountain bristlecone pines, in the subsection Balfourianae.
Pinus flexilis, the limber pine, is a species of pine tree in the family Pinaceae that occurs in the mountains of the Western United States, Mexico, and Canada. It is also called Rocky Mountain white pine.
Pinus strobus, commonly called the eastern white pine, northern white pine, white pine, Weymouth pine (British), and soft pine is a large pine native to eastern North America. It occurs from Newfoundland, Canada, west through the Great Lakes region to southeastern Manitoba and Minnesota, United States, and south along the Appalachian Mountains and upper Piedmont to northernmost Georgia and very rare in some of the higher elevations in northeastern Alabama. It is considered rare in Indiana.
Pinus contorta, with the common names lodgepole pine and shore pine, and also known as twisted pine, and contorta pine, is a common tree in western North America. It is common near the ocean shore and in dry montane forests to the subalpine, but is rare in lowland rain forests. Like all pines, it is an evergreen conifer.
Pinus virginiana, the Virginia pine, scrub pine, Jersey pine, possum pine, is a medium-sized tree, often found on poorer soils from Long Island in southern New York south through the Appalachian Mountains to western Tennessee and Alabama. The usual size range for this pine is 9–18 m, but can grow larger under optimum conditions. The trunk can be as large as 20 inches diameter. This tree prefers well-drained loam or clay, but will also grow on very poor, sandy soil, where it remains small and stunted. The typical life span is 65 to 90 years.
Jack pine, also known as grey pine or scrub pine, is a North American pine.
Coulter pine, or big-cone pine, is a conifer in the genus Pinus of the family Pinaceae. Coulter pine is a native evergreen conifer that lives up to 100 years of age. Coulter pine occurs in a mediterranean climate. Winter rains are infrequent, and the summer is dry with occasional summer thunderstorms. It 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. Although it has a limited range in the wild, the Coulter pine is a popular ornamental tree and is grown in many countries. Although geographically isolated, these Coulter pine populations were very similar in all of three morphological characteristics studies.Oleoresins were also similar.
The knobcone pine, Pinus attenuata, is a tree that grows in mild climates on poor soils. It ranges from the mountains of southern Oregon to Baja California with the greatest concentration in northern California and the Oregon-California border.
Pinus longaeva is a long-living species of bristlecone pine tree found in the higher mountains of California, Nevada, and Utah. Methuselah is a bristlecone pine that is 4,856 years old and has been credited as the oldest known living non-clonal organism on Earth. To protect it, the exact location of this tree is kept secret. In 1987, the bristlecone pine was designated one of Nevada's state trees.
Pinus aristata, the Rocky Mountain bristlecone pine or Colorado bristlecone pine is a long-lived species of bristlecone pine tree native to the United States. It is found in the Rocky Mountains in Colorado and northern New Mexico, with an isolated population in the San Francisco Peaks of Arizona. It is found at very high altitudes, from 2,100 to 4,000 meters in cold, dry subalpine climate conditions, often at the tree line, although it also forms extensive closed-canopy stands at somewhat lower elevations.
The Ancient Bristlecone Pine Forest is a protected area high in the White Mountains in Inyo County in eastern California.
Prometheus was the oldest known non-clonal organism, a Great Basin bristlecone pine tree growing near the tree line on Wheeler Peak in eastern Nevada, United States. The tree, which was at least 4,862 years old and possibly more than 5,000, was cut down in 1964 by a graduate student and United States Forest Service personnel for research purposes. Those involved did not know of its world-record age before the cutting, and the circumstances and decision-making process remain controversial.
Methuselah is a 4,856-year-old Great Basin bristlecone pine tree growing high in the White Mountains of Inyo County in eastern California. It is recognized as the non-clonal tree with the greatest confirmed age in the world. Its old age is a result of harsh weather and a lack of nutrients, which slow down the decaying process. The tree's name refers to the biblical patriarch Methuselah, who is said to have reached 969 years of age before his death, thus becoming synonymous with longevity or old age in many European languages including English.