''Betula glandulosa'', the American dwarf birch, also known as resin birch or shrub birch, is a species of

birch A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech- oak family Fagaceae. The genus ''Betula'' contains ...

native to North America.

Description

American dwarf birch is a multi-stemmed shrub typically growing to tall, often forming dense thickets. The trunks are slender, rarely over diameter, with smooth, dark brown bark. The leaves are nearly circular to oval, long and broad, with a toothed margin. The

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

ing catkins are erect, long and broad. It is closely related to the

dwarf birch ''Betula nana'', the dwarf birch, is a species of birch in the family Betulaceae, found mainly in the tundra of the Arctic region. Description It is a monoecious, deciduous shrub growing up to high. The bark is non-peeling and shiny red-coppe ...

(''Betula nana''), and is sometimes treated as a subspecies of it, as ''B. nana'' subsp. ''glandulosa''. It is distinguished from typical ''B. nana'' by the presence of glandular warts on the shoots and longer leaf petioles. Hybrids with several other birches occur.

Distribution and habitat

This plant occurs in

arctic The Arctic ( or ) is a polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenland), Finland, Iceland, N ...

and cool

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout ...

areas from

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S. ...

east to Newfoundland and southern

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland i ...

, and south at high altitudes to northern

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

Colorado Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the wes ...

, and the

Black Hills The Black Hills ( lkt, Ȟe Sápa; chy, Moʼȯhta-voʼhonáaeva; hid, awaxaawi shiibisha) is an isolated mountain range rising from the Great Plains of North America in western South Dakota and extending into Wyoming, United States. Black ...

South Dakota South Dakota (; Sioux: , ) is a U.S. state in the North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Lakota and Dakota Sioux Native American tribes, who comprise a large porti ...

in the west, and locally south to northern New York in the east. In the Arctic, it occurs down to sea level, while in the south of the range, it grows as high as altitude. It is typically a wetland species, growing in bogs, muskegs, or other moist and nutrient-deficient soils, but can be found in a wide variety of sites, ranging from rocky subarctic locales to boreal forests with deep, organic-rich soils. It is the most common shrub at treeline in interior Alaska, forming a nearly continuous zone between the treeline and alpine tundra.

Ecology

Many species of wildlife rely on this shrub as a food source, particularly ungulates such as moose, deer, caribou and elk. Its preference as a food source varies depending on the specific population; moose in Alberta, for example, are known to graze on it heavily, whereas moose in Alaska are observed to eat it at low levels. Bears, small mammals, birds, and insects also rely on the shrub as a food source. American dwarf birch provides cover for ptarmigans, and grizzly bears use it consistently to construct their dens. This species is valued for its erosion control potential, and has been used to help stabilize stream-banks.

References

Flora of North America: ''Betula glandulosa''RangeMap
*Hunt, D. (1993). ''Betula. Proceedings of the IDS Betula Symposium 2–4 October 1992''. International Dendrology Society.

External links

USDA Plants Profile for ''Betula glandulosa'' (resin birch)Calflora Database: ''Betula glandulosa'' (Resin birch)
glandulosa Flora of Subarctic America Flora of Western Canada Flora of Eastern Canada Flora of Alaska Flora of the Northwestern United States Flora of the Southwestern United States Flora of the Northeastern United States Flora of the Western United States Flora of California Flora of Greenland Flora of New Mexico Flora of the Cascade Range Flora of the Rocky Mountains Flora of the North-Central United States {{Fagales-stub