Abies grandis (grand fir, giant fir, lowland white fir, great silver fir, western white fir, Vancouver fir, or Oregon fir) is a fir native to the Pacific Northwest and Northern California of North America, occurring at altitudes of sea level to . It is a major constituent of the Grand Fir/Douglas Fir Ecoregion of the Cascade Range.
The tree typically grows to in height, and may be the tallest Abies species in the world. There are two varieties, the taller coast grand fir, found west of the Cascade Mountains, and the shorter interior grand fir, found east of the Cascades. It was first described in 1831 by David Douglas.
It is closely related to white fir. The bark was historically believed to have medicinal properties, and it is popular in the United States as a Christmas tree. Its lumber is a softwood, and it is harvested as a hem fir. It is used in paper-making, as well as construction for framing and flooring, where it is desired for its resistance to splitting and splintering.
Description
Abies grandis is a large evergreen conifer growing to tall, exceptionally , with a trunk diameter of up to . The dead tree tops sometimes fork into new growth. The bark is thick, reddish to gray (but purple within), furrowed, and divided into slender plates. The leaves are needle-like, flattened, long and wide by 0.5 mm thick, glossy dark green above, with two green-white bands of stomata below, and slightly notched at the tip. The leaf arrangement is spiral on the shoot, but with each leaf variably twisted at the base so they all lie in two more-or-less flat ranks on either side of the shoot. On the lower leaf surface, two green-white bands of stomata are prominent. The base of each leaf is twisted a variable amount so that the leaves are nearly coplanar.
The green-to-reddish cones are long and broad, with about 100–150 scales; the scale bracts are short, and hidden in the closed cone. The winged seeds are released when the cones disintegrate at maturity about 6 months after pollination.
Varieties
There are two varieties, probably better treated at subspecies rank though not yet formally published as such: Abies grandis var. grandis. Coast grand fir. Coastal lowland forests, at sea level to 900 m altitude, from Vancouver Island and coastal British Columbia, south to Sonoma County, California. A large, very fast-growing tree to 70 m tall. Foliage strongly flattened on all shoots. Cones slightly narrower (mostly less than 4 cm broad), with thinner, fairly flexible scales. Tolerates winter temperatures down to about -25° to -30 °C; growth on good sites may exceed 1.5 m per year when young. Abies grandis var. idahoensis. Interior grand fir. Interior forests, at (600–) 900–1800 m altitude, on the east slope of the Cascades in Washington and northern Oregon and in the Rocky Mountains from southeast British Columbia south to central Idaho, northeast Oregon and western Montana. A smaller, slow-growing tree to 40–45 m tall. Foliage not strongly flattened on all shoots, the leaves often raised above the shoot, particularly on upper crown shoots. Cones slightly stouter (mostly over 4 cm broad), with thicker, slightly woody scales. Tolerates winter temperatures down to about -40 °C; growth on good sites not exceeding 0.6 m per year even when young.
Grand fir is very closely related to white fir, with the interior variety idahoensis particularly similar to the western forms of white fir from western Oregon and California, intergrading with it where they meet in the Cascades of central Oregon.
Taxonomy
The species was first described by Scottish botanical explorer David Douglas, who in 1830 brought its seeds back to Britain; in 1831 he described specimens he had collected along the Columbia River in the Pacific Northwest.