Alaska paper birch

Silhouette - Alaska paper birch
  • Latin name: Betula neoalaskana Sarg.
  • French name: Bouleau d’Alaska
  • Synonym(s): Alaska white birch , Alaska birch
  • Taxonomic Serial Number: 183536
    509507 [syn. B. resinifera Britt.]
    195235 [syn. B. papyrifera var. neoalaskana (Sarg.) Raup]
    532504 [syn. B. papyrifera var. humilis (Regel) Fern. et Raup]
    195236 [syn. B. alaskana Sarg.]
Description

Leaves

  • Leaf with detail of resin dots on undersurface - Alaska paper birch

Form

  • Triangular to broadly oval
  • Tip long-tapered, sharp-pointed
  • Base broadly wedge-shaped
  • Tiny resin dots on lower surface, almost hairless
  • Veins 4 or 5 per side

Colour

  • Upper surface shiny dark green
  • Lower surface light yellowish-green

Length

  • 4–7 cm

Margin

  • Smooth
  • Teeth often gland-tipped
  • Each vein ends in a tooth, with 3–5 smaller intervening teeth

Buds

  • Lateral bud and leaf scar - Alaska paper birch

Form

  • Blunt, resinous, slightly hairy

Colour

  • Greenish-brown

Twigs

  • Winter twig - Alaska paper birch

Form

  • Slender with an abundance of fine short hairs
  • Covered with resin glands, sometimes large and crystalline and dense enough to conceal the twig surface

Colour

  • Bright reddish-brown

Flowers

Length

  • Pollen catkins 2.5–4 cm at pollination
  • Seed catkins 1–2 cm

Structure

  • Monoecious

Fruits

  • Fruit scale (left); winged nutlet (right) - Alaska paper birch

Form

  • Mature seed catkins blunt-tipped, drooping or slightly spreading from the dwarf shoots
  • Scales with 2 rounded lateral lobes pointing away from the central lobe or curved slightly downward

Length

  • Mature seed catkins about 2.5–3.5 cm
  • Nutlets twice as long as broad

Width

  • Wings much wider than the nutlet

Bark

Form

  • Thin, smooth
  • Peels off in papery layers (not as freely as white birch)

Colour

  • Dark reddish-brown when young, with age becoming creamy white or slightly pinkish

Size

Height

  • To 15 m

Diameter

  • To 20 cm

Tree form

  • Silhouette - Alaska paper birch

Forest-grown

Crown

  • Narrow, oval
  • Branches slender, stiffly upright, some with drooping tips

Habitat

Site

  • Bogs and poorly drained soils

Associated species

  • In pure stands or mixed with other species, especially black spruce
Distribution map
Distribution map - Alaska paper birch
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