||It has been suggested that Betula kenaica be merged into this article. (Discuss) Proposed since September 2014.|
|Natural range of Betula papyrifera|
Betula papyrifera (paper birch, also known as white birch and canoe birch) is a species of birch native to northern North America. It is the provincial tree of Saskatchewan and the state tree of New Hampshire.
|This section does not cite any references or sources. (February 2013)|
It is a medium-sized deciduous tree reaching 60 feet tall (18m), and exceptionally to 130 feet (40m) with a trunk up to 32 inches diameter (0.8m). They live to about 140 years. The bark is white, commonly brightly so, flaking in fine horizontal strips, and often with small black marks and scars. In individuals younger than five years, the bark appears brown with white lenticels, making the tree much harder to distinguish from other trees. The leaves are alternate, ovate, 1-5 in. long and 2-4 in. broad, with a doubly serrate margin. The leaf buds are conical and small. They are green-colored with brown edges. The flowers are wind-pollinated catkins 1.5 in. long growing from the tips of twigs. The fruit matures in the fall. The mature fruit is composed of numerous tiny winged seeds packed between the catkin bracts. They drop between September and spring.
Paper birch handles heat and humidity poorly and may only live 30 years in Zones 6 and up while trees in colder-climate regions can exceed 50 years and grow to much larger sizes. When stressed, it can succumb to bronze birch borer beetles.
Betula papyrifera has a wide range. It is found in interior (var. humilus) and south-central (var. kenaica) Alaska and in all provinces and territories of Canada, except Nunavut, as well as the northern continental United States, south to Pennsylvania and Washington, with small isolated populations further south in mountains to North Carolina, New Mexico, and Colorado. The most southerly stand in the Western United States is located in Lost Gulch in the City of Boulder Mountain Parks, an isolated Pleistocene relict that most likely reflects the southern reach of boreal vegetation into the area during the last Ice Ages.
Betula papyrifera is a pioneer species; for example, it is frequently an early invader after fire in Black Spruce Boreal forests. B. papyrifera requires high nutrients and sun exposure. The bark is highly weather-resistant. Often, the wood of a downed paper birch will rot away leaving the hollow bark intact. Birch bark is a winter staple food for moose. The nutritional quality is poor, but is important to wintering moose because of its sheer abundance. Although white-tailed deer consider birch a "secondary-choice food", it is an important dietary component. In Minnesota, white-tailed deer eat considerable amounts of paper birch leaves in the fall. Snowshoe hares browse paper birch seedlings.
The species is considered vulnerable in Indiana, imperiled in Illinois, Virginia, West Virginia and Wyoming, and critically imperiled in Colorado and Tennessee. When used in landscape planting, it should not be planted near black walnut as the chemical juglone, exuded from the roots of black walnut, is very toxic to paper birch.
Betula papyrifera has a soft, yet moderately heavy, white wood. It makes excellent high-yielding firewood if seasoned properly. Its bark is an excellent fire starter; it ignites at high temperatures even when wet.
While a paper birch does not have a very high overall economic value, it is used in furniture, flooring, popsicle sticks and oriented strand board. The sap is boiled down to produce birch syrup. Panels of bark can be fitted or sewn together to make cartons and boxes (a birchbark box is called a wiigwaasi-makakin the Anishinaabe language). The bark is also used to create a durable waterproof layer in the construction of sod-roofed houses.
It is frequently planted as an ornamental, however, due to its intolerance of high temperatures, Betula nigra, or river birch, is recommended for warm-climate areas.
- "The Plant List". The Plant List. Retrieved 2012-10-10.
- "Betula papyrifera". Flora of North America.
- "USDA GRIN Taxonomy".
- "Saskatchewan's Provincial Tree".
- "Fast New Hampshire Facts". NH.gov. Retrieved August 28, 2012.
- Cooper, David J. (Spring 1984). "Ecological Survey of the City of Boulder, Colorado Mountain Parks" (PDF). City of Boulder Parks and Recreation Department. p. 16. Retrieved 2011-09-16.
- Hogan, C. Michael (2008). "Black Spruce (Picea mariana)". GlobalTwitcher. Retrieved 2011-09-16.
- Ewing, Susan (April 1, 1996). The Great Alaska Nature Factbook. Portland, Oregon: Alaska Northwest Books. ISBN 978-0-88240-454-7.
- Bellis, Mary. "Popsicle - The History of the Popsicle". About.com. Retrieved 2011-09-16.
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