Betula papyrifera

Paper Birch

Paper Birch

Paper Birch, BWCA
Photo © by Earl J.S. Rook

Flora, fauna, earth, and sky...
The natural history of the northwoods

Name:
  • Betula, from the Latin for birch
  • papyrifera, from the Greek, papurus (papyrus), "paper" and the Latin, fero, "to bear, carry, bring"; "paper bearing"
  • Paper Birch, from the paper-like bark
  • Other common names include Canoe Birch, Silver Birch, White Birch, Bouleau blanc, Bouleau à papier (Qué), Papier-Birken (Ger)

Taxonomy:
  • Kingdom Plantae, the Plants
    • Division Magnoliophyta, the Angiosperms (flowering plants)
      • Class Magnoliopsida, the Dicotyledons
      • Subclass Hamamelididae
        • Order Fagales
          • Family Betulaceae, the Birches
            • Genus Betula, the Birches
  • Taxonomic Serial Number: 19489
  • Also known as Betula alaskana, Betula cordifolia, Betula neoalaskana
  • Betula is a genetically plastic genus, often with variation continuous between species. Hybridization is common. Paper Birch naturally hybridizes with almost every native birch species.

Description:
  • Medium sized, single or multiple stemmed, deciduous tree. In forests a slender trunk with a narrow crown, but in openings a wider crown spreading out from near the base. Multiple-stemmed trees are relatively common as a result of browsing by moose and snowhoe hares.
  • Height at maturity 70'-80' and 10"-12" in diameter, sometimes to 30".
  • Short-lived. Height growth ceases at about 60-70 years of age; few live more than 140 years.
  • Shallow-rooted: few roots deeper than 24" below the soil surface.
  • Bark reddish-brown on saplings; on mature trees thin, white, and smooth, often separating into papery strips, and easily peeled off in sheets.

Identification:

Distribution:
  • Alaska to Newfoundland,
  • Transcontinental distribution across northern North America.

Habitat:
  • Grows in climates ranging from boreal to humid and tolerates wide variations in the amount and pattern of precipitation. It grows at the northern limit of tree growth in arctic Canada and Alaska, in boreal spruce woodlands and forests, in montane and subalpine forests of the West, in wooded draws of the northern Great Plains, and in coniferous, deciduous, and, mixed forests of the Northeast and Lake States.
  • Shade-intolerant; abundant on burned or cut lands, often in pure stands. Restricted to openings in older forests.
  • Most abundant on rolling upland terrain and alluvial sites but grows on almost any soil and topographic situation, including mountain slopes, open slopes, rock slides, muskegs, and borders of bogs and swamps.
  • Soils: Grows best on deep, well-drained to moderately well-drained, sandy or silty soils common on glacial deposits. It grows on a wide range of soil textures from gravels to silts, and grows on organic bog and peat soils.
  • Birch shade is unfavorable for germination of birch seed, but spruce seedlings are common. By 120-150 years after fire, black or white spruce dominate. In boreal mixed woods, paper birch begin dying by 75 years after fire; Jack Pine (Pinus banksiana), Black Spruce (Picea mariana), and White Spruce (Picea glauca) begin to dominate or codominate. By 125 years most paper birch are dead. In Minnesota, often replaced by communities dominated by shrubs, particularly Beaked Hazel (Corylus cornuta). In boreal spruce ecosystems, paper birch forms nearly pure, pioneer communities on disturbed sites.
  • Rare in late successional or climax forests and generally restricted to openings. A principal component of boreal mixed woods in Canada because its pioneering habit is favored by the relatively frequent 50-125 year fire return interval. Codominants in mixed woods include Balsam Fir (Abies balsamifera), White Spruce (Picea glauca), Black Spruce (Picea mariana), Jack Pine (Pinus banksiana), and Quaking Aspen (Populus tremuloides)

Fire:
  • Rapidly colonizes open disturbed sites created by wildfire or windthrow, but lasts only one generation before being replaced by shade-tolerant conifers or northern hardwoods. Re-seeds aggressively after wildfire, often forming large, essentially pure stands.
  • Depending on the recovery of other species following fire, may also occur in mixed postfire stands with spruces, aspen, and other hardwoods.

Associates:

History:
  • During the last Ice Age, a part of the vast White Spruce forest which covered the Great Plains and eastern US, just south of the windswept tundra bordering the great ice sheets. One of the earliest species, along with spruce, to follow the retreating ice northward reaching the Canadian border soon after the ice had passed.
  • Native Americans used bark to make baskets, storage containers, mats, baby carriers, moose and bird calls, torches, household utensils, and, of course, canoes.
  • The strong and flexible wood was made into spears, bows, arrows, snowshoes, sleds, and other items

Uses:
  • Commercially for veneer, plywood, and pulpwood. It is easily worked and takes finishes and stains readily. Furniture, cabinets, and numerous specialty items are made from birch lumber.
  • Tree chips used for pulp and paper manufacture, reconstituted uses, and fuel.
  • Commonly used as fireplace and wood stove fuel
  • Graceful form and attractive bark make it a popular landscape plant.
  • The sap is made into syrup, wine, beer, and medicinal tonics.

Reproduction:
  • Reproduces by seed and vegetatively by root sprouts
  • Flowers, male and female, occur in separate, pendulous catkins on the same tree. Male catkins are partially formed in the fall, remain dormant in the winter, and expand to about 4" before flowering in the spring. Female catkins appear in the spring before the leaves are fully expanded.
  • Fruits winged nutlets, 0.06" long, 0.03" wide.
  • Seed production begins at about age 15, with optimum production at 40 to 70 years. Trees produce good seed crops about every other year.
  • Dispersal: The small, double-winged seeds are dispersed primarily by wind. Most seeds fall 100'-200' from the parent tree. Nearly all the seed is shed from September through November. A small percentage of the seeds can remain viable on the forest floor for several years.
  • Germination normally takes place in the spring following dispersal and is generally best on disturbed mineral or mixed mineral/organic soil. The small seeds are sensitive to soil moisture and temperature. Thus shade usually favors germination and initial establishment by preventing seedbeds from drying out and reaching excessively high temperatures. South or southwest exposures, excessively drained soils, insufficient rainfall, competing vegetation, and unshaded and undisturbed seedbeds deter establishment. Seedlings will not grow on soils with a pH less than 5.0. Although germination and early survival are often best on mineral soils, seedling growth is best on humus seedbeds in moderate or full sunlight. First year seedlings are about 2"-5".
  • Vegetative reproduction: Sprouts following cutting or fire from the stump base or root collar. Prolific sprouting common in young trees, with some individuals producing up to 100 sprouts. Sprout growth is rapid, sometimes up to 24" the first growing season, decreasing with age.
  • Phenology for NE Minnesota:
    • bud burst April
    • leafing out late April - early May
    • flowering begins April
    • pollen shed late April - May
    • seedfall begins August
    • leaf color change September
    • leaf fall late September - October

Propagation:
  • Best results are obtained by planting 2-year-old or older bare-root or containerized stock. Occasionally transplanted from the wild.
  • Also by grafting, air layering, rooting of cuttings, or tissue-culture.

Cultivation:
  • Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
  • Cultivars and species available by mail order from specialty suppliers or at local nurseries
  • Shade-intolerant
  • Leaf litter inhibits Jack Pine (Pinus banksiana), Red Pine (Pinus resinosa), and White Pine (Pinus strobus) seed germination.
  • Insects: Bronze Birch Borer the most serious insect pest. It attacks and can kill injured, overmature, or decadent trees. There are numerous defoliators of Paper Birch, but they rarely kill healthy trees.
  • Diseases: Bacteria or decay fungi enter through wounds and branch stubs, and roots which come in contact with the roots of other trees infected with root-rotting fungi.

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Last updated on 4 March, 2006