Populus trichocarpa

The black cottonwood (poplar) is in the willow or Salicaceae family and is native to western North America, from southern Alaska to northern California and extending into the interior. It can grow to a height of 50 m and a diameter of over 2 m. It has an extensive and aggressive root system, which can invade and damage drainage systems.

• Leaves are alternate, simple, elliptic with a wavy-toothed margin and an acute tip, 7–20 cm long, with a glossy dark green upper side and light grey-green underside. Petiole is reddish.
• Buds are conical, long, narrow and sticky, with a strong balsam scent in spring when they open.
• The species is dioecious, with female catkins 10–20 cm long in spring, and male catkins darker brown and 3–5 cm long. Each female seed capsule contains many minute seeds that are released attached to long, white cottony hairs that help them disperse in the wind in early summer.
• Bark is yellowish tan when young, becoming more gray, thick and deeply fissured on old trees.