Whitebark Pine
Encyclopedia
Pinus albicaulis, known commonly as Whitebark Pine, Pitch Pine, Scrub Pine, and Creeping Pine occurs in the mountains of the Western United States and Canada, specifically the subalpine
areas of the Sierra Nevada, the Cascade Range
, the Pacific Coast Ranges
, and the northern Rocky Mountains
– including the Greater Yellowstone Ecosystem
. It shares the common name Creeping Pine with several other "creeping pine" plants.
The Whitebark Pine is typically the highest-elevation pine tree of these mountains, marking the tree line. Thus, it is often found as krummholz
, trees dwarfed by exposure and growing close to the ground. In more favourable conditions, trees may grow to 20 metres (65.6 ft) in height, although some can reach up to 27 metres (88.6 ft).
group, Pinus subgenus Strobus, section Strobus and like all members of that group, the leaves
('needles') are in fascicles (bundles) of five, with a deciduous sheath. This distinguishes Whitebark Pine and relatives from the Lodgepole Pine (Pinus contorta)
, with two needles per fascicle, and Ponderosa Pine (Pinus ponderosa) and Jeffrey Pine (Pinus jeffreyi)
, which both have three per fascicle; these three all also have a persistent sheath at the base of each fascicle.
Distinguishing Whitebark Pine (Pinus albicaulis), from the related Limber Pine (Pinus flexilis)
, also a "white pine," is much more difficult, and requires seed or pollen cones
. In Pinus albicaulis, the cones are 4 centimetre long, dark purple when immature, and do not open on drying, but the scales easily break when they are removed by Clark's Nutcracker
(see below) to harvest the seeds. In Pinus flexilis, the cones are 6 centimetre long, green when immature, and open to release the seeds; the scales are not fragile. Whitebark Pines almost rarely has intact old cones lying under them, whereas Limber Pines usually do. The pollen cones of Whitebark Pine (Pinus albicaulis) are scarlet, and yellow in Limber Pine (Pinus flexilis).
Whitebark Pine (Pinus albicaulis) can also be hard to distinguish from Western White Pine (Pinus monticola)
in the absence of cones. However, Whitebark Pine needles are entire (smooth when rubbed gently in either direction), whereas Western White Pine needles are finely serrated (feeling rough when rubbed gently from tip to base). Whitebark Pine needles are also usually shorter, 4 centimetre long, overlapping in size with the larger 5 centimetre needles of the Western White Pine.
, the major seed disperser of the pine. Clark's Nutcrackers each cache about 30,000 to 100,000 each year in small, widely scattered caches usually under 2 to 3 cm of soil or gravelly substrate. Nutcrackers retrieve these seed caches during times of food scarcity and to feed their young. Cache sites selected by nutcrackers are often favorable for germination of seeds and survival of seedlings. Those caches not retrieved by time snow melts contribute to forest regeneration. Consequently,Whitebark Pine often grows in clumps of several trees, originating from a single cache of 2–15 or more seeds. Douglas Squirrel
s cut down and store Whitebark Pine cones in their midden
s. Grizzly Bear
s and American Black Bear
s often raid squirrel middens for Whitebark Pine seeds, an important pre-hibernation food. Squirrels, Northern Flicker
s, and Mountain Bluebird
s often nest in Whitebark Pines, and elk and Blue Grouse use Whitebark Pine communities as summer habitat.
and Mountain Pine Beetle
s. Whitebark deaths in North Cascades National Park
doubled from 2006 to 2011.
, a fungal disease that was introduced from Europe. In the northern Rocky Mountains of the U.S., Whitebark Pine mortality in some areas exceeds 90%, where the beetle infests 143000 acres (578.7 km²). Entire forest vistas, like that at Avalanche Ridge near Yellowstone National Park’s east gate, are expanses of dead, gray whitebarks. Cronartium ribicola occurs in Whitebark Pine to the northern limits of the species in the coastal ranges of British Columbia and the Canadian Rocky Mountains. The blister rust has also devastated the commercially-valuable Western White Pine in these areas, and made serious inroads in Limber Pine (Pinus flexilis) populations as well. Nearly 80 percent of Whitebark Pines in Mount Rainier National Park
are infected with blister rust.
There is currently no way to stop the spread and effects of blister rust. However, a small number of trees (fewer than 5%) in most populations harbor genetic resistance to blister rust. There have been some restoration efforts by the U.S. Forest Service and National Park Service in the northern Rocky Mountains. Restoration
efforts involve harvesting cones from potentially and known resistant Whitebark Pines, growing seedlings, and outplanting seedlings in suitable sites.
In California, where the Blister Rust is far less severe, Whitebark Pine (Pinus albicaulis) are still fairly common in the High Sierras.
in the western U.S. and Canada. Since 2000, the climate at high elevations has been warm enough for the beetles to reproduce within Whitebark Pine, often completing their life cycle within one year and enabling their populations to grow exponentially. These higher temperature trends have been attributed by some researchers to global warming
.
In 2007, the U.S. Fish and Wildlife Service estimated the beetles killed Whitebark Pines across half a million acres in the Wes; in 2009, beetles killed trees on 800000 acres (323,748.8 ha). the most since record-keeping began. The pine beetle upsurge has killed nearly 750,000 Whitebark Pines in the Greater Yellowstone Ecosystem
alone.
balancing their habitat and suppressing insect-disease threats. In the absence of low-level wildfire cycles, whitebark Pines in these stands are replaced by more shade-tolerant, fire-intolerant species such as Subalpine fir (Abies lasiocarpa) and Engelmann spruce (Picea engelmannii). In addition senescent and Blister Rust infected pine trees are not destroyed by natural periodic ground fires, further diminishing the Whitebark Pine forest's vitality and survival.
Subalpine
The subalpine zone is the biotic zone immediately below tree line around the world. Species that occur in this zone depend on the location of the zone on the Earth, for example, Snow Gum in Australia, or Subalpine Larch, Mountain Hemlock and Subalpine Fir in western North America.Trees in the...
areas of the Sierra Nevada, the Cascade Range
Cascade Range
The Cascade Range is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades...
, the Pacific Coast Ranges
Pacific Coast Ranges
The Pacific Coast Ranges and the Pacific Mountain System are the series of mountain ranges that stretch along the West Coast of North America from Alaska south to Northern and Central Mexico...
, and the northern Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
– including the Greater Yellowstone Ecosystem
Greater Yellowstone Ecosystem
The Greater Yellowstone Ecosystem is one of the last remaining large, nearly intact ecosystems in the northern temperate zone of the Earth and is partly located in Yellowstone National Park. Conflict over management has been controversial, and the area is a flagship site among conservation groups...
. It shares the common name Creeping Pine with several other "creeping pine" plants.
The Whitebark Pine is typically the highest-elevation pine tree of these mountains, marking the tree line. Thus, it is often found as krummholz
Krummholz
Krummholz or Krumholtz formation — also called Knieholz — is a particular feature of subarctic and subalpine tree line landscapes. Continual exposure to fierce, freezing winds causes vegetation to become stunted and deformed...
, trees dwarfed by exposure and growing close to the ground. In more favourable conditions, trees may grow to 20 metres (65.6 ft) in height, although some can reach up to 27 metres (88.6 ft).
Characteristics
Whitebark Pine (Pinus albicaulis) is a member of the white pinePinus classification
There are three main subgenera of Pinus, the subgenus Strobus , the subgenus Ducampopinus , and the subgenus Pinus...
group, Pinus subgenus Strobus, section Strobus and like all members of that group, the leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
('needles') are in fascicles (bundles) of five, with a deciduous sheath. This distinguishes Whitebark Pine and relatives from the Lodgepole Pine (Pinus contorta)
Lodgepole Pine
Lodgepole Pine, Pinus contorta, also known as Shore Pine, is a common tree in western North America. Like all pines, it is evergreen.-Subspecies:...
, with two needles per fascicle, and Ponderosa Pine (Pinus ponderosa) and Jeffrey Pine (Pinus jeffreyi)
Jeffrey Pine
The Jeffrey Pine, Pinus jeffreyi, named in honor of its botanist documenter John Jeffrey, is a North American pine related to Ponderosa Pine.-Distribution and habitat:...
, which both have three per fascicle; these three all also have a persistent sheath at the base of each fascicle.
Distinguishing Whitebark Pine (Pinus albicaulis), from the related Limber Pine (Pinus flexilis)
Limber Pine
The Limber Pine, Pinus flexilis, is a species of pine tree-the family Pinaceae that occurs in the mountains of the Western United States, Mexico, and Canada. It is also called Southwestern White Pine and Rocky Mountain White Pine...
, also a "white pine," is much more difficult, and requires seed or pollen cones
Conifer cone
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...
. In Pinus albicaulis, the cones are 4 centimetre long, dark purple when immature, and do not open on drying, but the scales easily break when they are removed by Clark's Nutcracker
Clark's Nutcracker
Clark's Nutcracker , sometimes referred to as Clark's Crow or Woodpecker Crow, is a passerine bird in the family Corvidae. It is slightly smaller than its Eurasian relative the Spotted Nutcracker . It is ashy-grey all over except for the black-and-white wings and central tail feathers...
(see below) to harvest the seeds. In Pinus flexilis, the cones are 6 centimetre long, green when immature, and open to release the seeds; the scales are not fragile. Whitebark Pines almost rarely has intact old cones lying under them, whereas Limber Pines usually do. The pollen cones of Whitebark Pine (Pinus albicaulis) are scarlet, and yellow in Limber Pine (Pinus flexilis).
Whitebark Pine (Pinus albicaulis) can also be hard to distinguish from Western White Pine (Pinus monticola)
Western White Pine
Western White Pine, Pinus monticola in the family Pinaceae, is a species of pine that occurs in the mountains of the western United States and Canada, specifically the Sierra Nevada, the Cascade Range, the Coast Range, and the northern Rocky Mountains. The tree extends down to sea level in many...
in the absence of cones. However, Whitebark Pine needles are entire (smooth when rubbed gently in either direction), whereas Western White Pine needles are finely serrated (feeling rough when rubbed gently from tip to base). Whitebark Pine needles are also usually shorter, 4 centimetre long, overlapping in size with the larger 5 centimetre needles of the Western White Pine.
Source of food
The Whitebark Pine is an important source of food for many granivorous birds and small mammals, including most importantly the Clark's NutcrackerClark's Nutcracker
Clark's Nutcracker , sometimes referred to as Clark's Crow or Woodpecker Crow, is a passerine bird in the family Corvidae. It is slightly smaller than its Eurasian relative the Spotted Nutcracker . It is ashy-grey all over except for the black-and-white wings and central tail feathers...
, the major seed disperser of the pine. Clark's Nutcrackers each cache about 30,000 to 100,000 each year in small, widely scattered caches usually under 2 to 3 cm of soil or gravelly substrate. Nutcrackers retrieve these seed caches during times of food scarcity and to feed their young. Cache sites selected by nutcrackers are often favorable for germination of seeds and survival of seedlings. Those caches not retrieved by time snow melts contribute to forest regeneration. Consequently,Whitebark Pine often grows in clumps of several trees, originating from a single cache of 2–15 or more seeds. Douglas Squirrel
Douglas Squirrel
The Douglas Squirrel is a pine squirrel found in the Pacific coastal states and provinces of North America. It is sometimes known as the Chickaree or Pine Squirrel, but since Chickaree is also used for the American Red Squirrel and Pine Squirrel for the genus Tamiasciurus, these alternative names...
s cut down and store Whitebark Pine cones in their midden
Midden
A midden, is an old dump for domestic waste which may consist of animal bone, human excrement, botanical material, vermin, shells, sherds, lithics , and other artifacts and ecofacts associated with past human occupation...
s. Grizzly Bear
Grizzly Bear
The grizzly bear , also known as the silvertip bear, the grizzly, or the North American brown bear, is a subspecies of brown bear that generally lives in the uplands of western North America...
s and American Black Bear
American black bear
The American black bear is a medium-sized bear native to North America. It is the continent's smallest and most common bear species. Black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in...
s often raid squirrel middens for Whitebark Pine seeds, an important pre-hibernation food. Squirrels, Northern Flicker
Northern Flicker
The Northern Flicker is a medium-sized member of the woodpecker family. It is native to most of North America, parts of Central America, Cuba, the Cayman Islands, and is one of the few woodpecker species that migrate. There are over 100 common names for the Northern Flicker...
s, and Mountain Bluebird
Mountain Bluebird
The Mountain Bluebird is a medium-sized bird weighing about 2-5 ounces, with a length from 15–20 cm . They have light underbellies and black eyes. Adult males have thin bills are bright turquoise-blue and somewhat lighter beneath. Adult females have duller blue wings and tail, grey breast,...
s often nest in Whitebark Pines, and elk and Blue Grouse use Whitebark Pine communities as summer habitat.
Threats
A study in the mid-2000s showed Whitebark Pine had declined by 41 percent in the Western Cascades, due to two threats: White Pine Blister RustCronartium ribicola
Cronartium ribicola is a species of rust fungi in the family Cronartiaceae that causes the disease white pine blister rust.Like many other rusts, C. ribicola is heteroecious, meaning it requires two host species to complete its lifecycle that includes five spore stages...
and Mountain Pine Beetle
Mountain pine beetle
The mountain pine beetle Dendroctonus ponderosae, is a species of bark beetle native to the forests of western North America from Mexico to central British Columbia. It has a hard black exoskeleton, and measures about 5 millimeters, about the size of a grain of rice.Mountain pine beetles inhabit...
s. Whitebark deaths in North Cascades National Park
North Cascades National Park
North Cascades National Park is a U.S. National Park located in the state of Washington. The park is the largest of the three National Park Service units that comprise the North Cascades National Park Service Complex. Several national wilderness areas and British Columbia parkland adjoin the...
doubled from 2006 to 2011.
White Pine Blister Rust
Many stands of Pinus albicaulis nearly range-wide are infected with White Pine Blister Rust (Cronartium ribicola)Cronartium ribicola
Cronartium ribicola is a species of rust fungi in the family Cronartiaceae that causes the disease white pine blister rust.Like many other rusts, C. ribicola is heteroecious, meaning it requires two host species to complete its lifecycle that includes five spore stages...
, a fungal disease that was introduced from Europe. In the northern Rocky Mountains of the U.S., Whitebark Pine mortality in some areas exceeds 90%, where the beetle infests 143000 acres (578.7 km²). Entire forest vistas, like that at Avalanche Ridge near Yellowstone National Park’s east gate, are expanses of dead, gray whitebarks. Cronartium ribicola occurs in Whitebark Pine to the northern limits of the species in the coastal ranges of British Columbia and the Canadian Rocky Mountains. The blister rust has also devastated the commercially-valuable Western White Pine in these areas, and made serious inroads in Limber Pine (Pinus flexilis) populations as well. Nearly 80 percent of Whitebark Pines in Mount Rainier National Park
Mount Rainier National Park
Mount Rainier National Park is a United States National Park located in southeast Pierce County and northeast Lewis County in Washington state. It was one of the US's earliest National Parks, having been established on March 2, 1899 as the fifth national park in the United States. The park contains...
are infected with blister rust.
There is currently no way to stop the spread and effects of blister rust. However, a small number of trees (fewer than 5%) in most populations harbor genetic resistance to blister rust. There have been some restoration efforts by the U.S. Forest Service and National Park Service in the northern Rocky Mountains. Restoration
Restoration ecology
-Definition:Restoration ecology is the scientific study and practice of renewing and restoring degraded, damaged, or destroyed ecosystems and habitats in the environment by active human intervention and action, within a short time frame...
efforts involve harvesting cones from potentially and known resistant Whitebark Pines, growing seedlings, and outplanting seedlings in suitable sites.
In California, where the Blister Rust is far less severe, Whitebark Pine (Pinus albicaulis) are still fairly common in the High Sierras.
Mountain Pine Beetle
There are widespread outbreaks of Mountain Pine BeetleMountain pine beetle
The mountain pine beetle Dendroctonus ponderosae, is a species of bark beetle native to the forests of western North America from Mexico to central British Columbia. It has a hard black exoskeleton, and measures about 5 millimeters, about the size of a grain of rice.Mountain pine beetles inhabit...
in the western U.S. and Canada. Since 2000, the climate at high elevations has been warm enough for the beetles to reproduce within Whitebark Pine, often completing their life cycle within one year and enabling their populations to grow exponentially. These higher temperature trends have been attributed by some researchers to global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...
.
In 2007, the U.S. Fish and Wildlife Service estimated the beetles killed Whitebark Pines across half a million acres in the Wes; in 2009, beetles killed trees on 800000 acres (323,748.8 ha). the most since record-keeping began. The pine beetle upsurge has killed nearly 750,000 Whitebark Pines in the Greater Yellowstone Ecosystem
Greater Yellowstone Ecosystem
The Greater Yellowstone Ecosystem is one of the last remaining large, nearly intact ecosystems in the northern temperate zone of the Earth and is partly located in Yellowstone National Park. Conflict over management has been controversial, and the area is a flagship site among conservation groups...
alone.
Fire suppression
Fire suppression has led to slow population declines over the last century by altering the health and composition dynamics of stands without the fire ecologyFire ecology
Fire ecology is concerned with the processes linking the natural incidence of fire in an ecosystem and the ecological effects of this fire. Many ecosystems, such as the North American prairie and chaparral ecosystems, and the South African savanna, have evolved with fire as a natural and necessary...
balancing their habitat and suppressing insect-disease threats. In the absence of low-level wildfire cycles, whitebark Pines in these stands are replaced by more shade-tolerant, fire-intolerant species such as Subalpine fir (Abies lasiocarpa) and Engelmann spruce (Picea engelmannii). In addition senescent and Blister Rust infected pine trees are not destroyed by natural periodic ground fires, further diminishing the Whitebark Pine forest's vitality and survival.
Protective efforts
On July 18, 2011, the U.S. Fish and Wildlife Service reported that the Whitebark Pine needed protection and that, without it, the tree would soon be extinct. However, the agency announced it would neither be able to list the tree as endangered nor protect the organism, as it lacked both the necessary staff and funding to do so.External links
- Pinus albicaulis from USDA Plants Profile
- Pinus albicaulis from Jepson Manual Treatment
- Pinus albicaulis from Gymnosperm Database
- Pinus albicaulis from Flora of North America
- Pinus albicaulis – U.C. Photos Gallery
- Whitebark Pine Communities from the United States Geological SurveyUnited States Geological SurveyThe United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...
- Official website of the Whitebark Foundation
- High Elevation White Pine-Pinus albicaulis from the USDA Forest Service's Rocky Mountain Research StationRocky Mountain Research StationThe Rocky Mountain Research Station is one of five regional units that make up the US Forest Service Research and Development organization — the most extensive natural resources research organization in the world. The station headquarters are located in Fort Collins, Colorado. The director is...