Jack Pine - Pinus banksiana

Jack pine is also commonly called scrub pine, Banksian pine, or Hudson Bay pine. It is a small-to medium-sized coniferous tree of the northern forests of the United States and Canada, where it is an important source of pulpwood, lumber, and round timber. It grows farther north than any other American pine and is the most widely distributed pine species in Canada. It is a pioneer species in succession and invades areas where mineral soil has been exposed by major disturbances such as fires. It usually grows in even-aged pure or mixed stands on less fertile and drier soils than those required by other native species in its range.

The major portion of the jack pine range is in Canada where its northern boundary extends eastward from the Mackenzie River in the Northwest Territories across the country to Cape Breton Island, NS. The range then extends southwest through Maine, New Hampshire, northern New York, central Quebec and northern Ontario, Michigan, extreme northwest Indiana, northeast Illinois, then northwest through Wisconsin, Minnesota, Manitoba, Saskatchewan, central Alberta, to extreme northeast British Columbia.

Within its range, jack pine is widely but not continuously distributed. In Canada it is most abundant in Ontario, and in the United States, the largest acreages are in Minnesota, Wisconsin, and Michigan (74). The only significant artificial extensions of the jack pine range have been on strip-mined areas in the central and northeastern States and on the sand hills of Nebraska.

Jack pine is usually found on sandy soils of the Spodosol and Entisol soil orders. It also grows on loamy soils, on thin soils over the granites and metamorphosed rocks of the Canadian Shield, over limestones, on peats, and on soil over permafrost. Jack pine can grow on very dry sandy or gravelly soils where other species can scarcely survive, but it grows best on well drained loamy sands where the midsummer water table is from 1.2 to 1.8 m (4 to 6 ft) below the surface. Jack pine does not grow naturally where the surface soil is alkaline, but it does grow on soils overlying limestone. It can grow on calcareous soils (pH 8.2) if a normal mycorrhizal association is present. In southeastern New Brunswick, owing to a long fire history, jack pine occupies vast areas of clayey soils and it is more common than red pine on xeric sites that have high nutrient levels.

In the Lake States and Canada, jack pine grows most commonly on level to gently rolling sand plains, usually of glacial outwash, fluvial, or lacustrine origin. It occurs less commonly on eskers, sand dunes, rock outcrops, and bald rock ridges. In the Lake States jack pine is found chiefly at elevations between 300 and 460 m (1,000 and 1,500 ft), with a maximum of about 610 m (2,000 ft) above sea level. In the East, jack pine grows on a variety of sandy sites from near sea level up to about 610 m (2,000 ft), with an outlier in New Hampshire at 2,500 ft.

The Jack Pine forest cover type (Society of American Foresters Type 1) typically originates after forest fires. It is found in pure, even-aged stands or as a majority of the stocking over vast areas of Canada and to a much lesser extent in the Lake States and the northeastern United States. In the boreal forest jack pine is also a component of three other forest cover types-Black Spruce (Type 12), Paper Birch (Type 18), and Aspen (Type 16). In the northern forest region it is a component of two forest cover types- Red Pine (Type 15) and Northern Pin Oak (Type 14). Outliers near southern fringes of the species' range are found in various types of hardwood forest.

Associated tree species, listed in order of presence on dry to mesic sites, include northern pin oak (Quercus ellipsoidalis), bur oak (Q. macrocarpa), red pine (Pinus resinosa), bigtooth aspen (Populus grandidentata), quaking aspen (P. tremuloides), paper birch (Betula papyrifera), northern red oak Quercus rubra), eastern white pine (Pinus strobus), red maple (Acer rubrum), balsam fir (Abies balsamea), white spruce (Picea glauca), black spruce (P. mariana), tamarack (Larix laricina), and balsam poplar (Populus balsamifera). In the boreal forest the most common associates are quaking aspen, paper birch, balsam fir, and black spruce. In the northern forest they are northern pin oak, red pine, quaking aspen, paper birch, and balsam fir. Associates are nearly always subordinate to jack pine except for aspen, paper birch, and red pine which may be coordinate (26,61). Infrequent associates in the northeastern United States and adjacent Canada include white oak (Quercus alba), pin cherry (Prunus pensylvanica), gray birch (Betula populifolia), red spruce (Picea rubens), and pitch pine (Pinus rigida).

Growth Rate: Under forest conditions, seedling growth is slow in the first 3 years but increases rapidly beginning in the fourth and fifth years. Seedlings attain a height of about 5 cm (2 in) the first year, 15 cm (6 in) at 2 years, and 30 to 90 cm (12 to 36 in) at 4 years. Early growth of 2-0 seedlings in plantations is more rapid, amounting to 30 to 45 cm (12 to 18 in) per year on medium sites.

During the first 20 years, jack pine in its native range is the fastest growing conifer other than tamarack. Seedlings reach 1.4 m (4.5 ft) tall in 5 to 8 years, depending on site. In the Lake States, 20-year-old stands with 2,470 trees per hectare (1,000/acre) on sites ranging from site index 12 to 21 m (40 to 70 ft) average between 5.5 and 9.8 m (18 and 32 ft) tall, 6.7 and 20.0 m² (29 and 87 ft²) in basal area, 5.8 and 10.2 cm (2.3 and 4.0 in) in d.b.h. (46), and 14 600 and 62 800 kg/ha (13,000 and 56,000 lb/acre) in ovendry weight of above-ground biomass.

Habit: In well-stocked stands, jack pine develops into a medium tall, slender tree with a narrow, open crown covering 30 to 45 percent of the stem. Crown ratios from 10 to 20 percent are not uncommon in dense stands. Open-grown jack pine develops a stocky stem of poor form and a wide, spreading crown with persistent branches, often to the ground. Overstocked stands produce weak, spindly stems that are susceptible to breakage by wind, ice, and snow.