White birch
Description
Leaves
Form
- Ovate or triangular, tip-pointed
- Widest below the middle
- Base broadly wedge-shaped, rounded, straight or cordate, and smooth-edged
- 9 veins per side or fewer
- Preformed leaves become hairless
- Neoformed leaves remain hairy, especially at the vein axils
Length
- 5–10 cm
Colour
- Upper surface dull green
- Lower surface lighter green
Margin
- Double-toothed
- Each vein ends in a large tooth with 3–5 smaller intervening teeth
- 33–55 teeth per side
Buds
Form
- Slender, tapering to a blunt point
- Resinous
Length
- 5–7 mm
Colour
- Scales greenish toward the base
- Brown toward the tip
Twigs
Form
- Slender, hairy, developing sparse warty resin glands
Colour
- Dark reddish-brown
Flowers
Form
- Pollen catkins in clusters of 1–3
- Seed catkins erect
Length
- Pollen catkins 1–3 cm, 9 cm at pollination
- Seed catkins 1–2 cm
Width
- Pollen catkins 2–4 mm in winter
Colour
- Stigmas pink or red
Structure
- Monoecious
Fruits
Form
- Mature seed catkins hang from dwarf shoots
- Scales variable, usually hairy, with 2 rounded lateral lobes diverging from a short, pointed central lobe
Length
- Mature seed catkins 3–5 cm
- Nutlets 1.5–2.5 mm
- Scales 2–3 mm
Width
- Nutlets half as wide as long
- Wings much wider than the nutlet
Timing
- Fruits and scales shed from September onward
Bark
Form
- Thin, smooth
- Often shedding in large sheets
Colour
- Dark red to almost black on young stems, becoming reddish-brown then bright creamy white
- Reddish-orange inner bark turns black
Wood
Texture
- Uniform, odourless
Colour
- Pale
Uses
- Tough pliable bark used for making canoes and ornaments
Size
Height
- In eastern Canada, to 25 m
- In western Canada, western white birch to 35 m, with peeling orange-white bark, and northwestern white birch to 20 m, with light reddish-brown bark
Diameter
- To 40 cm
Maximum age
- 120 years
Tree form
Forest-grown
Trunk
- Slender, often curved
- Usually distinct to midcrown or higher
Crown
- Narrowly oval, open
- Branches ascending
Habitat
Site
- Forest edges, lakeshores, and roadsides
- A wide variety of soils
Light tolerance
- Not shade-tolerant
Associated species
- In pure stands and mixed with various species such as other birches, pines, spruce, hemlocks, poplars, maples, balsam fir, northern red oak, and pin cherry
Range
Across Canada
Insects and diseases
Insects
- Birch casebearer
- Birch sawfly
- Hemlock looper
- Northern tent caterpillar
- Pale winged grey
- Saddleback looper
- Fall webworm
- Forest tent caterpillar
- Gypsy moth
- Eupithecia subfuscata (Haworth)
- Ambermarked birch leafminer
- Asian longhorned beetle
- Birch-aspen leafroller
- Birch budgall mite
- Birch leafminer
- Birch skeletonizer
- Bronze birch borer
- Ceanothus silk moth
- Fall cankerworm
- Late birch leaf edgeminer
- Saddled prominent
- Speckled green fruitworm
- Spring cankerworm
- White slaut
- Whitetriangle leafroller
Insects and diseases that are found most frequently and/or that cause the most damage in our Canadian forests.