Betula alleghaniensis

Yellow Birch

Yellow Birch
Photo courtesy Wisconsin State Herbarium and Kenneth J. Sytsma

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

Name:

• Betula, from the Latin for birch
• alleghaniensis, from the Latin, "of the Alleghanies"
• Common name from the color of the bark
• Other common names include Swamp Birch, Silver Birch, Gray Birch, merisier, bouleau jaune

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: 19481
• Also known as Betula lutea
• Known to hybridize with both our other native North Country birches.
  • Betula alleghaniensis × Betula papyrifera is seldom reported, but may actually be more common than realized in the northeastern states. In most features intermediate between the parents.
  • Betula alleghaniensis × Betula pumila, known as Betula × purpusii is rather common wherever the parent species occur together. The large shrubby plants show strikingly intermediate leaf characteristics.

Description:

• A native, deciduous tree to 75' in height.
• Stem
  • Trunk straight
  • Open-grown yellow birch crowns are long and wide spreading; in more dense forest crowns are short and irregularly rounded. The trunk usually divides into a few spreading branches but lateral shade produces a straight trunk that extends nearly to the top of the tree. In dense stands the trunk is free of branches for over half the height of the tree.
  • Twigs with odor and taste of wintergreen when crushed, glabrous to sparsely pubescent, usually covered with small resinous glands.
  • Bark somewhat lustrous, separating in thin layers which exfoliate and result in a finely shaggy appearance. On old trunks, deeply grooved and about ½" thick. Bark of young trunks and branches dark reddish brown, in maturity tan, yellowish, or grayish, lustrous, smooth, irregularly exfoliating, or sometimes darkening and remaining close; lenticels dark, horizontally expanded.
• Roots generally shallow but variable. There is a well-developed extensive lateral root system; roots spread horizontally or may penetrate more than 5'.
• Flowers monoecious
• Fruit a winged nutlet 0.13- to 0.14-inch (3.2-3.5-mm) long (not including the wings).Samaras with wings narrower than body, broadest near summit, not or only slightly extended beyond body apically.
• Slow growing, with an average lifespan of approximately 150 years, but can live over 300 years.

Identification:

Distribution:

• Eastern Minnesota to the Gaspé, south to northeastern Iowa, northern Illinois, northern Indiana, Ohio, Pennsylvania, and New Jersey; south through the Appalachians to northern Alabama and Georgia.
• The largest concentrations are found in Quebec, Ontario, New Brunswick, Maine, upper Michigan, and New York, with about 50% of the growing volume in Quebec. At the northwestern limit of its range in our area.

Habitat:

• Soils: occurs on moist, well-drained soils of uplands and mountain ravines. It occurs on various soil types including glacial tills, outwash sands, lacustrine deposits, shallow loess, and residual soils derived from sandstone, limestone, igneous, and metamorphic rock. The best growth occurs on well-drained fertile loams and moderately well-drained sandy loams. Even though growth is poor, yellow birch is often abundant where drainage is restricted. Yellow birch occurs on muck soils with pH 7.5 to 8.0. Birches (Betula spp.) are sensitive to soil phosphorus.
• Periodic droughts are damaging to yellow birch because of its shallow roots.
• Yellow birch is intermediate in shade tolerance. Yellow birch is described as opportunistic due to its habit of producing abundant small seed. Yellow birch seeds comprised a higher than expected proportion (compared to the abundance of mature trees) of the seed rain and seedbank of a mixed forest. The presence of yellow birch in mid- to late-successional stands depends on local disturbance; it cannot reproduce under a closed canopy and requires soil disturbance and light for seedling survival. The origin of the gap is apparently important; in upper Michigan, yellow birch apparently failed to establish readily in gaps formed by stem breakage because soil was undisturbed.
• Sugar maple seedlings produce an allelopathic substance that inhibits the root growth of yellow birch seedlings.
• A common early to mid-successional associate in aspen-birch stands. In northern hardwood ecosystems, yellow birch reaches maximum importance levels within 15 years of disturbance, and those levels are maintained for at least 100 years. On Isle Royale, a paper birch-dominated stand that originated after fire early in this century is undergoing canopy invasion by sugar maple and yellow birch.
• Second-growth stands usually contain approximately the same percentage of yellow birch as virgin stands. Yellow birch occurs on fine till with importance peaking at about 80 years. On sandy soils, the trend is indistinct, probably declining over time.
• Mid- to Late-Successional Stands: Yellow birch is abundant in mid- to late-successional balsam fir-yellow birch-paper birch-white spruce (Picea glauca) stands on Isle Royale. In many old-growth stands, yellow birch gradually decreases in importance as the stand ages.

Fire:

• Susceptible to fire injury due to its thin bark; young trees and seedlings generally do not survive even low-intensity fire. Mature trees may survive because the thin forest floor under large trees does not usually support severe or persistent surface fire.
• Though typically a poor sprouter after top-kill from fire, seed germination and seedling establishment are enhanced by fire disturbance. Low intensity fires in particular create favorable conditions for post-fire regeneration by reducing the hardwood leaf mat and exposing mineral soil, while leaving mature trees as a seed source.
• Heinselman suggested that the presence of yellow birch in old mixed forests is hard explain without fire disturbance; however, other authors describe yellow birch as opportunistic with respect to fire but not fire dependent.
• Typically occurs in forests with fire-free intervals of at least 150-300 years; the fire regime is characterized by crown and severe surface fires in combination. In the Great Lakes States presettlement northern hardwoods-pine-spruce-fir forests probably had a semieven-aged structure where less shade-tolerant components were maintained by long-return interval disturbances such as fire or windstorms. Most fires in these forests were severe surface fires, occurring only after prolonged drought, and usually affecting forests that were breaking up due to other factors (and thus had heavy fuels).

Associates:

• Trees: American mountain-ash (Sorbus americana),
• Shrubs: mountain maple, alternate-leaved dogwood (Cornus alternifolia), beaked hazelnut (Corylus cornuta), American fly honeysuckle (Lonicera canadensis), Canada elderberry (Sambucus canadensis), Canada yew (Taxus canadensis), and mapleleaf viburnum (Viburnum acerifolium)
• Herbs:
• Ground Covers:
• Mammals: Browsed by moose, white-tailed deer, and snowshoe hare. Deer consume large numbers of seedlings in summer, and prefer green leaves and woody stems in fall. Red squirrel cut and store mature strobili, eat yellow birch seeds, and also feed on birch sap. Beaver and porcupine chew the bark.
• Birds: seeds are consumed by common redpoll, pine siskin, chickadees, and other songbirds. Ruffed grouse feed on seeds, catkins, and buds. The yellow-bellied sapsucker uses yellow birch as a summer food source.

History:

• Ojibwe
  • Bark used to make storage containers, sap dishes, rice baskets, buckets, trays and winnowing dishes.
  • Bark placed on the coffins when burying the dead.
  • Bark used to make birch bark canoes. Bark used to build dwellings and lodges.
  • Sap and maple sap used for a pleasant beverage drink
  • Decoction of bark taken for internal blood diseases.
  • Compound decoction of inner bark taken as a diuretic.

Uses:

• An economically important source of lumber. The wood is heavy, strong, and close-grained. It is used for furniture, cabinetry, charcoal, pulp, interior finish, veneer, tool handles, boxes, woodenware, and interior doors.
• Tapped for sap which is used to make an edible syrup.
• Tea can be made from the twigs and/or inner bark.
• Chips can be used to produce ethanol and other products.

Reproduction:

• Rreproduces primarily by seed; seedlings and young saplings will sprout but sprouts are weak and short lived. Older trees do not sprout.
• First produces seed at about 40 years, with optimum seed production at about 70 years of age. Good seed crops are produced at 1-4 year intervals with limited seed production in the intervening seasons. A prolific seed producer in good years, seed viability is usually quite good though declining significantly in the second year on the ground.
• Seed is disseminated by wind, with most falling after the onset of cold weather. The winged seeds may travel nearly a mile over crusted snow though most end up within an area roughly equivalent to four times the height of the tree.
• Seeds contain a water-soluble germination inhibitor, inactivated by light. Yellow birch seeds germinate and grow best on moist mineral soil enriched with humus; bare mineral soil and duff alone are unsuitable substrates. However, in undisturbed stands, germination of yellow birch seeds usually occurs on mossy logs, decayed wood, in cracks in boulders and on windthrown tree hummocks. Optimum germination of yellow birch occurs at 59 to 61 degrees Fahrenheit (15-16 deg C).
• Seedlings require overhead light, crown expansion space, and plentiful soil moisture and nutrients to compete with faster growing associates; conditions found in gaps are conducive to yellow birch seedling establishment. Some shade improves seedling survival. Mortality of yellow birch seedlings is usually very high, reported to be as high as 97%. Seedling survival is better on disturbed microsites; seedlings that germinate on litter are unlikely to survive. Seedlings surviving their first year survive to sapling and larger stages only where there is sufficient light. Growth is better on humus over sandy loams than on decayed logs, mineral soil, or litter.
• The pistillate catkins of yellow birch form in the fall, and finish development from late May to early June. The fruit ripens from late August to early September. The phenology of yellow birch in northern Minnesota was reported as follows:
  • flower appearance April 2 to May 16
  • initial bud swell April 6 to May 1
  • leaf out May 3 to May 25
  • anthesis May 13 to May 29
  • seed fall (initiation) August 6
  • leaf fall September 26 to October 4

Propagation:

• By seed. Under artificial conditions, seed dormancy is broken by stratification or by exposure of imbibed seed to cool-white fluorescent light.
• Also by greenwood cuttings and grafting.

Cultivation:

• Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
• Growth rate Rapid
• Cultivars and species available by mail order from specialty suppliers or at local nurseries

Links:

• Fire Effects Information System

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