|Young jack pine|
|Subgenus:||P. subg. Pinus|
|Section:||P. sect. Trifoliae|
|Subsection:||P. subsect. Contortae|
Distribution and habitat
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.
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.
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.
Its leaves are needle-shaped, evergreen, in fascicles of two, needle-like, straight or slightly twisted, stiff, sharp-pointed, light yellowish-green, spread apart; edges toothed and 2–4 cm (3⁄4–1+1⁄2 in) long. The bundle-sheath is persistent. The buds are blunt pointed, up to 15 mm long, reddish-brown, and resinous. On vigorous shoots, there is more than one cyclic component. The bark is thin, reddish-brown to gray in color in juvenile stages. As the tree matures it becomes dark brown and flaky. The wood is moderately hard and heavy, weak, light brown colour. The seed cones vary in shape, being rectangular to oval, cone shaped, straight or curved inward. The cones are 3–5 cm (1+1⁄4–2 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.
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. 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.
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.
Closed, mature cones
- 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.
- "Pinus banksiana Lamb.". World Checklist of Selected Plant Families. Royal Botanic Gardens, Kew – via The Plant List. Note that this website has been superseded by World Flora Online
- "Pinus divaricata". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
- "Pinus divaricata". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; Australian National Botanic Gardens.
- 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.
- 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). Vol. 1 – via Southern Research Station.
- "Pinus banksiana Lamb" (PDF). Center for Wood Anatomy Research, Forest Products Library, United States Forest Service. Archived from the original (PDF) on 2012-03-08. Retrieved 2010-12-27.
- 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.
- Cameron, H. (1953). "Melting Point of the Bonding Material in Lodgepole Pine and Jack Pine Cones". Silviculture Leaflet (86).
- Wyse, Sarah V; Brown, Jerusha E; Hulme, Philip E (2019-11-01). Zenni, Rafael D (ed.). "Seed release by a serotinous pine in the absence of fire: implications for invasion into temperate regions". AoB Plants. 11 (6): plz077. doi:10.1093/aobpla/plz077. ISSN 2041-2851. PMC 6900966. PMID 31844510.
- "USFWS: Managing the forest for the Kirtland's warbler". www.fws.gov. Retrieved 2021-10-05.
- Blouin, Glen. An Eclectic Guide to Trees: east of the rockies. 2001. Boston Mills Press, Erin, Ontario. pp 152-159.
- Trees of Canada; Author John Laird Farrar