jack pine

Jack Pine
A young Jack Pine
Conservation status
Least Concern (IUCN 2.3)
Scientific classification
Kingdom:	Plantae
Division:	Pinophyta
Class:	Pinopsida
Order:	Pinales
Family:	Pinaceae
Genus:	Pinus
Subgenus:	Pinus
Species:	P. banksiana
Binomial name
Pinus banksiana Lamb.

Pinus banksiana forest

The Jack Pine (Pinus banksiana) is a North American pine with its native range in Canada east of the Rocky Mountains from Northwest Territories to Nova Scotia, and the northeast of the United States from Minnesota to Maine, with the southernmost part of the range just into northwest Indiana. In the far west of its range, it hybridizes readily with the closely related lodgepole pine (P. contorta). The cone for the Jack pine tree is usually 5 cm and curved at the tip.^[1]

Etymology

The Jack Pine has a long list of minor alternative names, including eastern jack pine, gray pine, black pine and scrub pine; the last more commonly refers to Virginia Pine (P. virginiana), and Digger Pine to P. sabineana. The Canadian French name is Pin gris or (incorrectly) Cyprès.

Morphology

It is a large tree, ranging from 9–22 m (30–72 ft) in height. Some jack pines are shrub-sized, due to poor growing conditions. The jack pine does not usually grow perfectly straight but when mature has an irregular shape similar to the pitch pine. 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.

Foliage

The leaves are in fascicles of two, needle-like, twisted, slightly yellowish-green, and 2–4 cm (0.8–1.6 in) long. The cones are 3–5 cm (1.2–2.0 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. The typical case is in a fire, however cones on the lower branches can open when temperatures reach 27°C due to the heat being reflected off the ground. Additionally, when temperatures reach -46°C, the cones will open, due to the nature of the resin.

Ecology

Kirtland's Warbler (Dendroica kirtlandii), an endangered bird, depends on pure stands of young jack pine in a very limited area in the north of the Lower Peninsula of Michigan for breeding. Mature jack pine forests are usually open, and the fall of their needles creates acidic soil, so 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.^[2]

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.^[2]

Insects that attack jack pine stands include white pine weevil (Pissodes strobi), jack pine sawfly, and jack pine budworm.^[2]

Commercial uses

• hydro pole - mainly in Canada
• decking

References

Bibliography

• Conifer Specialist Group (1998). Pinus banksiana. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 12 May 2006.

Wikimedia Commons has media related to: Pinus banksiana

• Burns, R.M. 1990. Silvics of North America. Vol. 1 Conifers. USDS.
• National Geographic Field guide to tree's of North America.