Only five evergreens are native to Iowa. They are eastern white pine (Pinus strobus), redcedar, balsam fir, common juniper and yew. Evergreen or conifer trees differ from hardwoods or deciduous trees in that the leaves are needle like and the reproductive organs are borne in cones instead of flowers.
Habitat: Found growing on sandy or rocky steep wooded slopes. Can be found in the eastern half of Iowa but mainly in the extreme northeast.
Hardiness: Zones 5 through 7
Growth Rate: Moderate to Rapid
Mature Shape: Pyramidal
Height: 50-80 feet
Width: 40-50 feet
Site Requirements: White pines grow best in well-drained upland soils, but are adaptable. They have intermediate shade tolerance.
Flowering Dates: May - June
Seed Dispersal Dates: August - September
Seed Bearing Age: 5-10 years
Seed Bearing Frequency: Every 3 to 10 years
Seed Stratification: Prechill for 2 months at 34°F to 40°F.
White pine is easy to identify. Its leaves or needles occur in bundles or fascicles of five, 3-5 inches long, bluish green, with fine white lines or stomata. The cones are 3-6 inches long, gradually tapering, with cone scales without prickles and light tan to whitish in color on outer edge of the scales. The terminal buds are ovoid in shape, about 3/8 of an inch long, tapering to an abrupt slender tip, and have light brown scales. The bark on young trees is smooth and light gray, becoming dark gray to black with flat plates separated by shallow fissures on older trees.
The fine-textured leaves and the asymmetric shape of older trees make white pine one of the easiest conifers to identify from a distance. Its curve upper branches have a pronounced upward shape, and the length of its limbs often varies considerably from one whorl to the next. Most pines will overwinter with 2-3 years of needles, white pine looses all but the current years needles in the early fall.
White pine is native to northeast Iowa, plus isolated native stands in Hardin, and Muscatine counties. Even though it is not native in most of Iowa, it is a common tree in Iowa's landscape because it has been planted extensively for ornamental purposes, Christmas trees, wildlife habitat, windbreaks and timber production.
Naturally, it grows on bluffs, ridges and wooded slopes on soils with good internal drainage. Plantings do best on well drained soils, with moderately good moisture holding capacity, and soils that are slightly acidic. Plantings on dry, exposed, calcareous soils will often fail. On good sites, white pine will grow 50-90 feet in height; as a young tree growth rate is moderately fast (2-3 feet per year), decreasing with age.
White pine was the species the lumber industry was founded upon in the Northeastern United States. It was the leader in the lumber markets and still demands an important place in todays market. The wood of white pine is light, soft, and easily worked. It shrinks and swells very little, making it ideal for doors and sashes. It is also used for boxes, crates, toys, and many other items.