Jack pine

Pinus banksiana ranges from 9–22 metres (30–72 ft) in height. Some jack pines are shrub-sized, due to poor growing conditions. Although it varies among populations, jack pine trees do not usually grow particularly straight, resulting in an irregular shape similar to that of pitch pine (Pinus rigida). This pine often forms pure stands on sandy or rocky soil. Many populations are 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. Other populations have not been shaped by regular stand-replacing fires and have reduced serotiny. A population on the Maine coast is apparently not reliant on fire for reproduction, and some stands have developed several age classes. Populations with lower serotiny are often found on soils that are in some way limiting to faster-growing competition, such as soils shallow to bedrock, shallow to water table, or very young soils. 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. …

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.

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. Insects that attack jack pine stands include the white pine weevil (Pissodes strobi), Swaine jack pine sawfly (Neodiprion swainei), and jack pine budworm (Choristoneura pinus). Fossil evidence shows the jack pine survived the glacial period in the Appalachian and Ozark Mountains.

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.