Jack pine

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Jack pine
Pinus banksiana.jpg
Young jack pine
Scientific classification edit
Kingdom: Plantae
Clade: Tracheophytes
(unranked): Gymnospermae
Division: Pinophyta
Class: Pinopsida
Order: Pinales
Family: Pinaceae
Genus: Pinus
Subgenus: P. subg. Pinus
Section: P. sect. Trifoliae
Subsection: P. subsect. Contortae
P. banksiana
Binomial name
Pinus banksiana
Pinus banksiana range map.png
Native range
  • Pinus divaricata (Aiton) Dum.Cours.
  • Pinus divaricata (Aiton) Sudw. nom. illeg.
  • Pinus hudsonica Poir.
  • Pinus rupestris Michx.f.
  • Pinus sylvestris var. divaricata Aiton

Jack pine (Pinus banksiana) is an eastern North American pine. Its native range in Canada is east of the Rocky Mountains from the Mackenzie River in the Northwest Territories to Cape Breton Island in Nova Scotia, and the north-central and northeast of the United States from Minnesota to Maine, with the southernmost part of the range just into northwest Indiana and northwest Pennsylvania. It is also known as grey pine[5] and scrub pine.[5][6]

In the far west of its range, Pinus banksiana hybridizes readily with the closely related lodgepole pine (Pinus contorta). The species epithet banksiana is after the English botanist Sir Joseph Banks.[7]


Closed, mature cones
Pollen cones
The Jack Pine (1917) by Tom Thomson, painted in Algonquin Park, Ontario.

Pinus banksiana ranges from 9–22 m (30–72 ft) in height. Some jack pines are shrub-sized, due to poor growing conditions. They do not usually grow perfectly straight, resulting in an irregular shape similar to pitch pine (Pinus rigida). This pine often forms pure stands on sandy or rocky soil. It is fire-adapted to stand-replacing fires, with the cones remaining closed for many years, until a forest fire kills the mature trees and opens the cones, reseeding the burnt ground.

The leaves are in fascicles of two, needle-like, twisted, slightly yellowish-green, and 2–4 cm (341+12 in) long.

Jack pine cones are usually 5 cm (2 in) and curved at the tip.[8] The cones are 3–5 cm (1+14–2 in) long, the scales with a small, fragile prickle that usually wears off before maturity, leaving the cones smooth.

Unusually for a pine, the cones normally point forward along the branch, sometimes curling around it. That is an easy way to tell it apart from the similar lodgepole pine in more western areas of North America. The cones on mature trees are serotinous. They open when exposed to intense heat, greater than or equal to 50 °C (122 °F). The typical case is in a fire, however cones on the lower branches can open when temperatures reach 27 °C (81 °F) due to the heat being reflected off the ground. Additionally, when temperatures reach −46 °C (−51 °F), the cones will open, due to the nature of the resin.[citation needed]


P. banksiana forest with Vaccinium groundcover in Neil's Harbour, Nova Scotia.

Kirtland's warbler (Setophaga kirtlandii), a formerly endangered bird, depends on pure stands of young jack pine in a very limited area in the north of the Lower and Upper Peninsulas of Michigan for breeding. Most known nesting areas are limited to Crawford, Oscoda, and Ogemaw counties.[9] Mature jack pine forests are usually open and blueberries are often abundant in the understory.

Young jack pines are an alternate host for sweet fern blister rust (Cronartium comptoniae). Infected sweet ferns (Comptonia peregrina) release powdery orange spores in the summer and nearby trees become infected in the fall. Diseased trees show vertical orange cankers on the trunk and galls on the lower branches. The disease does not tend to affect older trees.[10]

Jack pines are also susceptible to scleroderris canker (Gremmeniella abietina). This disease manifests by yellowing at the base of the needles. Prolonged exposure may lead to eventual death of the tree.[10]

Insects that attack jack pine stands include the white pine weevil (Pissodes strobi), jack pine sawfly, and jack pine budworm.[10]

Commercial uses[edit]

Like other species of pine, Pinus banksiana has use as timber, although its wood tends to be knotty and not highly resistant to decay. Products include pulpwood, fuel, decking, and utility poles.[7]


  1. ^ Farjon, A. (2013). "Pinus banksiana". IUCN Red List of Threatened Species. 2013: e.T42346A2974230. doi:10.2305/IUCN.UK.2013-1.RLTS.T42346A2974230.en. Retrieved 12 November 2021.
  2. ^ "Pinus banksiana Lamb.". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew – via The Plant List.
  3. ^ "Pinus divaricata". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
  4. ^ "Pinus divaricata". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew.
  5. ^ a b New Brunswick House of Assembly (1847). Reports Relating to the Project of Constructing a Railway and a Line of Electro-magnetic Telegraph Through the Province of New Brunswick from Halifax to Quebec. J. Simpson.
  6. ^ Burns, R.M. (1990). "Pinus banksiana". In Burns, Russell M.; Honkala, Barbara H. (eds.). Conifers. Silvics of North America. Washington, D.C.: United States Forest Service (USFS), United States Department of Agriculture (USDA). 1 – via Southern Research Station (www.srs.fs.fed.us).
  7. ^ a b "Pinus banksiana Lamb" (PDF). Center for Wood Anatomy Research, Forest Products Library, United States Forest Service. Retrieved 2010-12-27.
  8. ^ Moore, Gerry; Kershner, Bruce; Craig Tufts; Daniel Mathews; Gil Nelson; Spellenberg, Richard; Thieret, John W.; Terry Purinton; Block, Andrew (2008). National Wildlife Federation Field Guide to Trees of North America. New York: Sterling. p. 68. ISBN 978-1-4027-3875-3.
  9. ^ "USFWS: Managing the forest for the Kirtland's warbler". www.fws.gov. Retrieved 2021-10-05.
  10. ^ a b c Blouin, Glen. An Eclectic Guide to Trees: east of the rockies. 2001. Boston Mills Press, Erin, Ontario. pp 152-159.


External links[edit]