black cottonwood

It is a large tree, growing to a height of 30 to 50 m (98 to 164 ft) and a trunk diameter over 2 m (6+1⁄2 ft). It ranks 3rd in poplar species in the American Forests Champion Tree Registry. It is normally fairly short-lived, but some trees may live up to 400 years. A cottonwood in Willamette Mission State Park near Salem, Oregon, holds the national and world records. Last measured in April 2008, this black cottonwood was found to be standing at 47 m (155 ft) tall, 8.8 m (29 ft) around, with 527 points. The bark is grey and covered with lenticels, becoming thick and deeply fissured on old trees. The bark can become hard enough to cause sparks when cut with a chainsaw. The stem is grey in the older parts and light brown in younger parts. The crown is usually roughly conical and quite dense. In large trees, the lower branches droop downwards. Spur shoots are common. The wood has a light coloring and a straight grain. The leaves are usually 7–20 centimetres (2+3⁄4–7+3⁄4 in) long with a glossy, dark green upper side and glaucous, light grey-green underside; larger leaves may be up to 30 cm (11+3⁄4 in) long and may be produced on stump sprouts and very vigorous young trees. The leaves are alternate, elliptical with a crenate margin and an acute tip, and reticulate venation. The petiole is reddish. …

The native range of P. trichocarpa covers large sections of western North America. It extends from Southeast Alaska's Kodiak Island and Cook Inlet to latitude 62° 30° N., through British Columbia and the forested areas of Washington and Oregon, to the mountains in southern California and northern Baja California (31°N). It is also found inland, generally on the west side of the Rocky Mountains, in British Columbia, southwestern Alberta, western Montana, and north-to-central Idaho. Scattered small populations have been noted in southeastern Alberta, eastern Montana, western Wyoming, Utah, and Nevada. Black cottonwood grows on alluvial sites, riparian habitats, and moist woods on mountain slopes, from sea level to elevations of 2,100–2,750 m (6,890–9,020 ft). It often forms extensive stands on bottomlands of major streams and rivers at low elevations along the Pacific Coast, west of the Cascade Range. In eastern Washington and other dry areas, it is restricted to protected valleys and canyon bottoms, along streambanks, and edges of ponds and meadows. It grows on a variety of soils from moist silts, gravels, and sands to rich humus, loams, and occasionally clays. Black cottonwood is a pioneer species that grows best in full sunlight and commonly establishes on recently disturbed alluvium. …

Although the most populous cottonwood of the Pacific Northwest, it hybridizes with the region's three other species: balsam poplar, plains cottonwood, and narrowleaf cottonwood; all four have similar appearances and provide habitats for various animals. Cottonwoods are shade intolerant. Black cottonwood thrives by colonizing disturbed sites, but can be replaced by conifers. The wood is relatively weak and waterlogged, often splitting during freezes. It is susceptible to rot as well. Woodpeckers create cavities which various animals can use for nests. Larger birds nest in the large upper branches. Beavers use the trees as food and dam-building material.

Conservation. Populus trichocarpa was evaluated by NatureServe in 2016, but with they consider it a subspecies of Populus balsamifera. Under this name they rated it as a secure subspecies (T5).

The tree was and is significant for many Native American tribes of the Western United States. Some Native Americans consumed cottonwood inner bark and sap, feeding their horses the inner bark and foliage. The wood, roots and bark have been used for firewood, canoe making, rope, fish traps, baskets and structures. The gum-like sap was used as a glue or as waterproofing. The Quinault used it for post wood. The Cowlitz made the base (hearth board) of their fire-making tool, a bow drill, with its wood. The Squaxin cut young branches for building sweat lodges.

It is grown as an ornamental tree, valued for its fast growth and scented foliage in spring, detectable from over 100 m distance. The roots are however invasive, and it can damage the foundations of buildings on shrinkable clay soils if planted nearby (Mitchel 1996). Branches can be added to potted plants to stimulate rooting.

The Chehalis believed that the tree was intelligent and had a form of special physical agency, moving on its own without the need of wind. Due to this belief, they refused to use it for firewood.