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Pinus albicaulis

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(Redirected fromWhitebark pine)
Not to be confused withPinus bungeana,also called white-barked pine.

Whitebark pine
A stand of whitebark pines atCrater Lake National ParkinOregon

Vulnerable(NatureServe)[2]
Scientific classificationEdit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Gymnospermae
Division: Pinophyta
Class: Pinopsida
Order: Pinales
Family: Pinaceae
Genus: Pinus
Subgenus: P.subg.Strobus
Section: P.sect.Quinquefoliae
Subsection: P.subsect.Strobus
Species:
P. albicaulis
Binomial name
Pinus albicaulis
Natural range ofPinus albicaulis
Synonyms[3]
  • Apinus albicaulis(Engelm.) Rydb.
  • Pinus cembroidesNewb. 1857 not Zucc. 1832
  • Pinus flexilisvar.albicaulis(Engelm.) Engelm.
  • Pinus flexilissubsp.albicaulis(Engelm.) Engelm.
  • Pinus shastaCarrière
Pinus albicaulisis the only type of tree on the summit ofPywiack DomeinYosemite National Park

Pinus albicaulis,known by the common nameswhitebark pine,white bark pine,white pine,pitch pine,scrub pine,andcreeping pine,[4]is aconifertree native to the mountains of the western United States and Canada, specificallysubalpineareas of theSierra Nevada,Cascade Range,Pacific Coast Ranges,Rocky Mountains,andRuby Mountains.It shares the common name "creeping pine" withseveral other plants.

The whitebark pine is typically the highest-elevationpinetree found in these mountain ranges and often marks thetree line.Thus, it is often found askrummholz,trees growing close to the ground that have been dwarfed by exposure. In more favorable conditions, the trees may grow to 29 meters (95 ft) in height.

Identification

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Pinus albicaulisleaves are in fascicles (bundles) of five, and the cone is dark purple when immature (Mount Rainier National Park)

Whitebark pine is a member of thewhite pinegroup, thePinussubgenusStrobus,and the sectionStrobus;like all members of this group, theleaves(needles) are infascicles(bundles) of five[5]with adeciduoussheath. This distinguishes whitebark pine and its relatives from thelodgepole pine(Pinus contorta), with two needles per fascicle, as well as theponderosa pine(Pinus ponderosa) andJeffrey pine(Pinus jeffreyi), which both have three needles per fascicle; all three of these species also have a persistent sheath at the base of each fascicle. Whitebark pine owes its name to the light gray bark of its young specimens.[5]

Distinguishing whitebark pine (Pinus albicaulis), from the relatedlimber pine(Pinus flexilis), also a member of the white pine group, is much more difficult, and usually requires seed or pollencones.InPinus albicaulis,the seed-bearing female cones are4–7 centimeters (1+1⁄2–3 in) long, dark purple when immature,[5]and do not open on drying, but the scales easily break when they are removed by theClark's nutcrackerto harvest the seeds; rarely are there intact old cones in the litter beneath the trees. Its pollen cones are scarlet.[6]

InPinus flexilis,the cones are6–12 cm (2+1⁄2–4+1⁄2in) long, green when immature, and open to release the seeds; the scales are not fragile. Their pollen cones are yellow, and there are usually intact old cones found beneath them.

Whitebark pine can also be hard to distinguish from thewestern white pine(Pinus monticola) in the absence of cones. However, whitebark pine needles are yellow-green[5]and entire (smooth when rubbed gently in either direction), whereas western white pine needles are silvery green[5]and finely serrated (feeling rough when rubbed gently from tip to base). Whitebark pine needles are also usually shorter, 3–7 cm (1–3 in) long,[5]though still overlapping in size with the larger 5–10 cm (2–4 in) needles of the western white pine.

Distribution

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Whitebark pine (Pinus albicaulis) can be found at high elevation in theRocky Mountainsfrom centralBritish Columbiato westernWyoming.[5]It occurs in the timberline zone of theCascadesand coastal ranges from British Columbia to theSierra Nevada,as well as most high ranges between the Rockies and Cascades, such as theBlue Mountains.[5]It is also populous in subalpine forests of Montana and Idaho.[5]

Ecology

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The whitebark pine,Pinus albicaulis,atMount Rainier National Park

The whitebark pine is an important source of food for manygranivorousbirds and small mammals, including most importantly theClark's nutcracker(Nucifraga columbiana), the major seed disperser of the pine.[5]Clark's nutcrackers each cache about 30,000 to 100,000 seeds each year in small, widely scattered caches, usually under2 to 3 cm (3⁄4to1+1⁄4in) 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 the time the snow melts contribute to forest regeneration. Consequently, whitebark pine often grows in clumps of several trees, originating from a single cache of two to 15 or more seeds.

Other animals also depend upon the whitebark pine.Douglas squirrelscut down and store whitebark pine cones in theirmiddens.Grizzly bearsandAmerican black bearsoften raid squirrel middens for whitebark pine seeds,[5]an important pre-hibernation food. Squirrels,northern flickers,andmountain bluebirdsoften nest in whitebark pines, andelkandblue grouse[5]use whitebark pine communities as summer habitat.

Fallen needles under these trees serve as beds that are used by deer and wild sheep seeking shelter during stormy weather.[7]

Threats

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The whitebark pine has been classified as endangered by theIUCN.[1]Severe population decline in whitebark pine communities is attributed to various causes, most significantly infection withwhite pine blister rust,recent outbreaks ofmountain pine beetles(2000–2014), disturbances in wildlandfire ecology(includingfire suppression), forest succession, and climate change. A study in the mid-2000s showed that whitebark pine had declined by 41 percent in the western Cascades due to two primary threats: blister rust and pine beetles.[8]Whitebark deaths inNorth Cascades National Parkdoubled from 2006 to 2011.[8]

White pine blister rust

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Further information:Cronartium ribicola

Many stands ofPinus albicaulisacross the species' entire natural range are infected with white pine blister rust (Cronartium ribicola), afungaldisease introduced from Europe. In the northern Rocky Mountains of the United States, whitebark pine mortality in some areas exceeds 90 percent, where the disease infests nearly 143,000 acres (580 km2).Cronartium ribicolaoccurs 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 inMount Rainier National Parkare infected with blister rust.[8]

There is currently no effective method for controlling 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.[5]Restoration effortsundertaken by theU.S. Forest Service,Bureau of Land Management,andNational Park Servicein the northern Rocky Mountains involve harvesting cones from potentially and known resistant whitebark pines, growing seedlings, and outplanting seedlings in suitable sites. InCalifornia,where the blister rust is far less severe, whitebark pine is still fairly common in theHigh Sierras.[9]

Mountain pine beetle

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Unusually large outbreaks of mountain pine beetle (Dendroctonus ponderosae), a species ofbark beetlenative to western North America, have also contributed significantly to the widespread destruction of whitebark pine stands.[10]The beetles both lay their eggs and introduce pathogenic fungi into their host trees, which include many other species of pine, and the combination of larval feeding and fungal colonization is typically sufficient to kill old or unhealthy trees. However, the beetles have recently expanded their attacks to younger, healthier trees as well as older trees, and climate change has been implicated as the primary culprit. Since 2000, the climate at high elevations has warmed enough for the beetles to reproduce within whitebark pine, often completing their life cycle within one year and enabling their populations to grow exponentially. Entire forest vistas, like that at Avalanche Ridge nearYellowstone National Park’s east gate, have become expanses of dead gray whitebarks.[11]Scientists have attributed the recent warming trend to anthropogenicglobal warming.[8][12]

In 2007, theU.S. Fish and Wildlife Serviceestimated that beetles had killed whitebark pines across 500,000 acres (200,000 ha) in the West, while in 2009, beetles were estimated to have killed trees on 800,000 acres (320,000 ha), the most since record-keeping began.[8]The pine beetle upsurge has killed nearly 750,000 whitebark pines in theGreater Yellowstone Ecosystemalone.[as of?]

Fire suppression

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Fire suppression has led to slow population declines over the last century by altering the health and composition dynamics of stands without the fire ecology balancing their habitat and suppressing insect-disease threats.[13]In the absence of low-level wildfire cycles, whitebark pines in these stands are replaced by more shade-tolerant, fire-intolerant species such assubalpine fir(Abies lasiocarpa) andEngelmann spruce(Picea engelmannii). In addition,senescentand blister rust-infected pine trees are not destroyed by natural periodic ground fires, further diminishing the whitebark pine forest's vitality and survival.[14]

Protective efforts

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In 2012 the Canadian federal government declared whitebark pineendangeredin accordance with theSpecies at Risk Act.Accordingly, it became the first federally listed endangered tree in western Canada.[15]In 2022 theU.S. Fish & Wildlife Servicealso acted. It listed whitebark pine in the lowest category of vulnerability: "threatened." Four distinct threats were described, beginning withwhite pine blister rustas "the primary stressor."Mountain pine beetle,altered fire regimes, and "the effects of climate change" add to the challenges.[16]This listing marks the first occasion in which a tree regarded as ecologically important over a vast range in the United States is acknowledged as vulnerable to extinction.[17]

In response to the ongoing decline of the tree throughout its range, the Whitebark Pine Ecosystem Foundation was formed. Their mission is to raise awareness and promote conservation by sponsoring restoration projects, publishing a newsletter called "Nutcracker Notes", and hosting an annual science and management workshop for anyone interested in whitebark pine.[18]This U.S. group collaborates closely with the Whitebark Pine Ecosystem Foundation of Canada.[19]

Uses

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Whitebark pine seeds

Many Native Americans, including theSalish peoples,have been known to eat the seeds from the cones of this tree.[20][5]They were roasted, made into porridge, and mixed with dry berries.[5]

References

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  1. ^abMahalovich, M.; Stritch, L. (2013)."Pinus albicaulis".IUCN Red List of Threatened Species.2013:e.T39049A2885918.doi:10.2305/IUCN.UK.2013-1.RLTS.T39049A2885918.en.RetrievedNovember 19,2021.
  2. ^NatureServe (2024)."Pinus albicaulis".Arlington, Virginia.RetrievedSeptember 5,2024.
  3. ^"Pinus albicaulis".World Checklist of Selected Plant Families.Royal Botanic Gardens, Kew– viaThe Plant List.Note that this website has been superseded byWorld Flora Online
  4. ^Earle, Christopher J., ed. (2018)."Pinus albicaulis".The Gymnosperm Database.
  5. ^abcdefghijklmnoArno, Stephen F.; Hammerly, Ramona P. (2020) [1977].Northwest Trees: Identifying & Understanding the Region's Native Trees(field guide ed.). Seattle:Mountaineers Books.pp. 26, 35–43.ISBN978-1-68051-329-5.OCLC1141235469.
  6. ^Roady, Laura (2010)."Whitebark Pine".Montana Outdoors.Montana Fish, Wildlife & Parks.RetrievedMarch 15,2015.
  7. ^Peattie, Donald Culross(1953).A Natural History of Western Trees.New York:Bonanza Books.p. 33.
  8. ^abcdeWelch, Craig (November 6, 2011)."Climate change, beetle may doom rugged pine".Seattle Times.RetrievedSeptember 9,2022.
  9. ^Brown, Matthew (December 14, 2022)."Whitebark pine that feeds grizzlies is threatened, US says".AP News.RetrievedDecember 14,2022.
  10. ^Kershner, Bruce; et al. (2008).National Wildlife Federation Field Guide to Trees of North America.New York: Sterling. p. 80.ISBN978-1-4027-3875-3.
  11. ^Petit, Charles (January 30, 2007)."In the Rockies, Pines Die and Bears Feel It".New York Times.Archived fromthe originalon February 6, 2012.RetrievedJuly 7,2012.
  12. ^Ross Reynolds (June 9, 2015)."Can A Dying Tree Species Be Saved At Crater Lake?".KUOW.
  13. ^Kendall, K.C; Keane, R.E. (2001). "Whitebark pine decline: Infection, mortality, and population trends". InTomback, D.F.;Arno, S.F.; Keane, R.E. (eds.).Whitebark pine communities: ecology and restoration.Washington, D.C.: Island Press. pp. 221–242.
  14. ^Lorenz, T. J.; Aubry, C.; Shoal, R. (2008).A review of the literature on seed fate in whitebark pine and the life history traits of Clark's nutcracker and pine squirrels(PDF).Portland, OR: U.S. Dept. of Agriculture, Forest Service, Pacific Northwest Research Station.OCLC222226528.
  15. ^Zimmer, Carl (January 13, 2023)."For Trees Under Threat, Flight May Be Best Response".The New York Times.New York Times.
  16. ^U.S. Fish and Wildlife Service (December 15, 2022)."Endangered and Threatened Wildlife and Plants; Threatened Species Status With Section 4(d) Rule for Whitebark Pine (Pinus albicaulis)"(PDF).Federal Register.87(240): 76882–76917.
  17. ^Center for Biological Diversity."Whitebark Pine Protected as Threatened Under Endangered Species Act".RetrievedJanuary 13,2023.
  18. ^Whitebark Pine Ecosystem Foundation
  19. ^Whitebark Pine Ecosystem Foundation of Canada
  20. ^Whitney, Stephen (1985).Western Forests (The Audubon Society Nature Guides).New York: Knopf. p.408.ISBN0-394-73127-1.

Further reading

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