White Birch (Betula papyrifera)

 
  
 
 
 
Description
White Birch
General Appearance
  • Is a medium sized deciduous tree.
  • Crown is small with ascending branches.
  • Bark is reddish-brown on young trees, maturing into whitish-cream colour.
  • Mature bark peels easily into thin sheets.
Size
  • Grows up to 30 metres (98.4 feet) in height.
Flowers
  • Small fruiting bodies called catkins hang from branches.
  • Staminate (male) cylindrical catkins, range from 4 to 10 centimetres (1.57 to 3.93 inches) in length.
  • Pistillate (female) cylindrical catkins, range from 2.5 to 5 centimetres (0.98 to 1.96 inches) in length.
Fruit
  • Small, broadly-winged nutlets called samaras.
Leaves
White Birch leaves and bark
  • Alternate, simple and on slender stalks.
  • Oval shaped, tapering to a point.
  • Irregularly toothed.
  • Range from 2.5 to 19 centimetres (0.98 to 7.48 inches) in length.
  • Dark green on top and slightly paler with tufts of hairs in the axils of the veins on the underside.
Distribution
  • White birch is a minor component of upland boreal stands and more common and widespread in moist wooded areas and along river banks.
  • Is found throughout central and northern parts of the province.
Natural History

Habitat
  • Is found on soils ranging from acidic to silty-loam, though it grows best in well-drained sandy or silty-loam soils.
  • Requires adequate moisture and full sun for growth as it does not tolerate dry or fully shaded sites.
Reproduction and Growth
  • Monoecious ? male and female flowers are found on the same tree.
  • Staminate (male) catkins form in fall, remain dormant over winter, and mature in the spring.
  • Pistillate (female) flowers are borne in cylindrical catkins. Two or three catkins are arranged on lateral spur shoots, disintegrating once mature.
  • Once pollinated, female catkins will develop seeds, beginning to ripen in early August until mid-September.
  • Seed dispersal begins soon after ripening.
  • The winged-seed is easily dispersed by the wind.
  • Reproduction is mainly by seed but this species has limited capacity to reproduce asexually from spouts following a disturbance such as harvest or wildfire.
  • Seed has the capacity to lie dormant for up to two years until moisture conditions are favourable for germination.
Conservation and Management

Status
White Birch is classified as Secure in the General Status of Alberta Wild Species report. See:

 
 
 
 
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This information published to the web on March 30, 2016.