Populus trichocarpa (syn. Populus balsamifera subsp. trichocarpa) Salicaceae
Black Poplar, Black Cottonwood pop-U-lus tri-ko-KAR-pa
- Deciduous tree, to 40 ft (12 m) in 15 years, finally to 150 ft (45 m), trunk long and straight, narrow crown. Bark dark gray-brown with age, in flat-topped ridges alongside V-shaped grooves. Winter buds round or slightly angled, about 2 cm long with 6-7 scales, long pointed, orange-brown, very resinous and fragrant (balsam odor); apparently the fragrance is especially pronounced in the spring as the leaves unfold. Leaves alternate, simple, broadly ovate, 7-12 cm long, base usually rounded (sometimes wedge- or heart-shaped), finely toothed, dark green above, silvery green below, often with brown resin blotches, petiole round, not flattened. Flowers in long catkins, male (pollen) catkins 4-5 cm; female (seed) catkins 6-8 cm long, extending to 12-15 cm prior to seed release. The seed catkins bear nearly spherical capsules, about 4 mm, which split into 3 parts to release silky tufts ("cotton") with attached small seeds (about 2 mm long). Terminal buds 17-20 mm long with 6-7 visible scales, lateral buds parallel to twig.
- Sun, prefers moist situations, but tolerates poor and dry soils. Wood very brittle. Female trees release a substantial amount of "cotton", which some consider a nuisance.
- Hardy to USDA Zone 4 Native range from southern Alaska to southern California, east to the Rocky Mountains. More recently considered a subspecies of the Eastern Balsam Poplar, Populus balsamifera.
- trichocarpa: hairy fruited; from the Greek thrix, a hair, and karpos, fruit.
- Corvallis: many at the confluence of Marys River and the Willamette River.