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Black cottonwood

Silhouette - black cottonwood
  • Latin name: Populus balsamifera ssp. trichocarpa (Torr. et A. Gray) Brayshaw
  • French name: Peuplier de l'Ouest
  • Synonym(s): Western balsam poplar
  • Taxonomic Serial Number: 22455
    195735 [syn. P. trichocarpa Torr. et A. Gray]
Description

Leaves

  • Leaf - black cottonwood

Form

  • Broadly ovate, tip long drawn-out
  • Base usually rounded, sometimes wedge-shaped or slightly heart-shaped
  • No warty glands at the base
  • Lower surface mostly hairless

Length

  • 7–12 cm

Colour

  • Upper surface dark green
  • Lower surface silvery green, usually stained with brownish resin blotches

Margin

  • Finely toothed with many short, rounded teeth that turn inward at their tips (sometimes partially smooth)

Petiole

  • Hairy
  • Round in cross-section
  • 3–4 cm long
  • Green

Buds

  • Lateral bud and leaf scar - black cottonwood

Form

  • Terminal bud round or slightly angled
  • Slender, long-pointed
  • Very resinous, fragrant
  • 6–7 scales, sometimes fringed with hairs
  • Lateral leaf buds parallel to the twig
  • Pollen flower buds stout with thickened scales
  • Leaf scars small, triangular

Length

  • 17–20 mm

Colour

  • Orange-brown

Twigs

  • Lateral bud and leaf scar - black cottonwood

Form

  • Moderately stout, hairy
  • Round to slightly angular in cross-section
  • Lenticels large, sparse

Colour

  • Orange-brown

Flowers

Length

  • Pollen catkins 4–5 cm
  • Seed catkins 6–8 cm

Structure

  • Dioecious

Fruits

  • Fruit capsule - black cottonwood
  • Fruit capsule scales; outer surface (left), inner surface (right) - black cottonwood

Form

  • Mature seed catkins hairy, bearing many closely spaced capsules
  • Capsules nearly globular, tip short
  • Covered with short hairs
  • Splitting into 3 parts when mature

Length

  • Mature seed catkins 12–15 cm
  • Capsules 3–4 mm
  • Seeds 2 mm

Bark

Form

  • Smooth when young, with age separating into flat-topped ridges with irregular V-shaped furrows

Colour

  • Greyish-green or yellowish-grey when young, becoming dark greyish-brown

Size

Height

  • To 35 m
  • The largest broadleaf tree native to British Columbia

Diameter

  • To 120 cm

Maximum age

  • 165 years

Tree form

  • Silhouette - black cottonwood

Forest-grown

Trunk

  • Long, straight

Crown

  • Narrow, somewhat columnar
  • Open, with a few stout ascending branches

Root system

  • Wide-spreading, with a few large roots, penetrating obliquely to the water table or a layer of hardened soil

Habitat

Site

  • At lower and middle elevations
  • On bottomlands
  • Loose, porous, sandy or gravelly soils
Insects and diseases

Insects and diseases that are found most frequently and/or that cause the most damage in our Canadian forests.

Photos
Distribution map
Distribution map - black cottonwood

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