General – large-sized, averaging 22 – 36 m (72 – 118 ft) high, evergreen conifer. Crown full, spreading, generally irregularly shaped. Branchlets slender, gray-green to orange-brown in color. Trunk shows little taper and is generally branchless for over 1/2 its height. Trunk bark on young trees, thin, smooth and gray-green in color. Later becoming thick, red-brown to gray-brown with prominent broad ridges and furrows.
Jack Pine Leaves – evergreen, 7.5 – 12.5 cm (3 – 5 in) long, with five blue-green, slender needles per fascicle. A fascicle sheath is not present. Needles appear blue because of 3 or more lines of stomata.
Flowers – monoecious, males cylindrical, yellow, in clusters near branch tips; females light green, tinged in red, at ends of branches, appearing in May.
Fruit – cones are 10 – 17.5 cm (4 – 7 in) long, cylindrical, with thin, rounded cone scales, very resinous. Cones are borne on a long stalk. Maturing August to September.
Found throughout Northwestern Ontario but most common in the southwestern area areas. Does well on dry/fresh, even shallow and stony, coarse loamy soils. In the overstory usually grows in mixed association with other species.
In general, on dry sites the understory vegetation is usually of one or more species of blueberries, bush-honeysuckle and clubmoss. The moist, rich sites support a ground vegetation made up principally of wild sarsaparilla, and intermediate sites have ground vegetation containing various amounts of the above with dogwood and wild lily- of-the -valley.
White pine is a valuable timber species. Although the natural population is much depleted now, it is still preferred for softwood lumber. Builders of sailing ships once sought the tall, straight white pine for masts. The best trees in British North America were stamped by the Crown and reserved for the Royal Navy.