Lofty elevations, favorable climate and four distinct seasons
Idaho is the perfect home for “softwood” trees.
Softwoods have needles instead of the broad leaves found on hardwood trees such as cherry, walnut, and oak. Softwoods are also known as “conifers” or cone-bearing trees because they reproduce using seed containers called cones.
Softwood lumber is lightweight and flexible, yet strong and easy to saw, plane, and nail. These properties make it ideal for home construction, and its long, strong fibers make excellent paper products.
People sometimes use the words “pine trees” when referring to softwoods. While the Idaho softwood forest contains some species of pine (ponderosa pine, lodgepole pine, and western white pine — Idaho’s state tree), it also is home to hemlock, western larch, western red cedar, Engelmann spruce, Douglas-fir, subalpine fir, and grand fir.
Trees Live in Neighborhoods
More than 20 tree species live in Idaho’s forests, and each has a preferred growing range. Many factors contribute to the relative suitability of a growing range for each species of tree. While soil composition, moisture, slope direction, inter-species competition, microclimate, and history of fire each play a role, elevation is the most important factor in defining a tree’s “neighborhood.” As elevation increases, temperatures decrease and moisture levels rise. Trees that require more water and can withstand colder temperatures tend to be found higher on the slopes. Other species that can withstand higher temperatures and drier soils grow at lower elevations.
Major Commercial Softwood Species
Of the ten major softwood species, eight are extremely important for their commercial value. These species account for more than 85% of the timber volume of Idaho’s forestlands.
Lodgepole Pine
Named for the tall, slender lodgepoles used to make teepees, lodgepole pines still provide shelter as framing or finishing lumber in our homes. Large stands of lodgepole pine are a sure sign that a wildfire once burned the area — lodgepole seeds are released from their cones by the heat of fire.
Western Hemlock
Western Hemlock is found in cool, moist, shady sites throughout central and northern Idaho. Its grain characteristics make it ideal for moulding, baseboards, window and door components, and stair railings. Hemlocks act as weather vanes in the forest, as their top-most branch bends away from the direction of the prevailing wind.
Unlike most conifers, the western larch loses its needles anually, bringing fall color to Idaho’s evergreen forests. Also called the “tamarack,” this species favors upper elevations with cool temperatures and moderate precipitation. Western larch’s reddish-brown wood is tight-grained and very durable, making it ideal for plywood, flooring, and interior/exterior trim.
Western White Pine
Idaho’s state tree was decimated by blister rust disease that was brought over from France on ornamental shrubs in 1910. Thanks to forestry research, blister-rust-resistant white pines have been developed, and are being planted in Idaho’s forests. The light, strong wood of the white pine is used to make window frames, paneling, shelving, and door frame
Douglas-fir
Despite its name, the Douglas-fir is not a true fir tree, but is more closely related to the hemlock. The exceptionally strong wood of this species has been used extensively for structural framing lumber. Also known as “red fir,” this species often reaches heights of 100 to 130 feet.
Ponderosa Pine
Found in drier sites at middle to lower elevations, ponderosa pine often grows in exclusive, single-species stands. Its fire-resistant bark enables the ponderosa pine to survive while other species are burned out. The aromatic, light-yellow wood of the ponderosa pine is made into boards that are used for trim, shelving, and interior paneling.
Slow-growing, long-lived, and exceptionally resistant to decay, western redcedar is a shade loving species. Native Americans once used western redcedar wood to make baskets and clothing. Today, we use western redcedar in siding and other specialty lumber products.
Grand Fir
Often called “white fir,” grand fir grows prolifically in the mountainous regions of Idaho. Noted for its straight, even grain and long fibers, this species is used to product dimensional lumber and lywood.
More information:
- Trees of Idaho An IFPC/Forest Service booklet. (PDF format, 2.6Mb)
- Shade Loving Trees? UI Extension Forestry Information Series
- Rocky Mountain Tree-Ring Research
- Trees of Idaho An IFPC/Forest Service booklet. (PDF format, 2.6Mb)
- RMRS (Rocky Mountain Research Station)
- Rocky Mountain Tree-Ring Research