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European White Birch - Betula pendula
Native to Europe and some parts of high-altitude Asia; introduced to
North America as an ornamental species, it has escaped and in some cases
becomes invasive, out-competing native species and becoming the dominant
forest tree. Little is known about the ecological effects of this
import.
Also commonly called silver birch or weeping birch.
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European White Birch is a medium-sized
deciduous tree in the birch family (Betulaceae). The
pyramidal shape of the crown becomes rounded with a
graceful, somewhat pendulous branching habit, and grows to a
height of 40 to 50 feet and width of 10 to 20 feet. Young
twigs are thin and usually pendulous. The white bark becomes
blackish with age. Simple, alternate leaves are broadly
ovate, sometimes rhomboidal to diamond shaped, wedge-shaped
or truncate at base, 1 to 3 inches long, coarsely doubly
serrate, slender tapered at apex, dotted with glands on both
surfaces and yellow to yellow green in fall. Flowers are
tightly packed in catkins found at the end of the
branchlets. Flowering occurs in April-May.
Habitat: Environmental condition that seem to favor
establishment and growth include 1) an available seed source
from planted or escaped specimens, 2) sunny conditions, at
least initially, 3) disturbed soil surfaces, and 4) acidic,
nutrient-poor soils. It can be found in disturbed quarries,
bogs, and wetlands. In urban forests, the species likely
will be found with some other exotic plant species.
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This tree was started from seed 13 years ago. |

Tree damaged by Bronze Birch Borer (Agrilus anxius)
Photo: Steven Katovich, USDA Forest
Service, Bugwood.org |
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Distribution: European White Birch is reported
invasive in Kentucky, Maryland, Washington, and Wisconsin. Escaped
populations of European white birch tend to be relatively
uncommon, and little is known about the ecological impacts
of the species in North America. At one Long Island site the
species has become a co-dominant forest tree, and is
reproducing via seed. In southeastern Massachusetts the tree
has colonized forest openings where it may be competing with
its native congener, gray birch. In eastern Kentucky it has
been planted on strip mines and in some cases become
invasive. It can compete with native plant species for
available resources.
Control and Management: The practice of keeping birch trees
as "leave trees" during logging should be discouraged.
Manual- Girdle trees- remove bark and phloem layer from 4
inch band around trunk; sheer- cut stems with shears or
chain saws then apply herbicides because cut stems tend to
sprout new stems from the cut base. Chemical- It can be
effectively controlled using any of several readily
available general use herbicides such as triclophr. There
are many possible ways to apply such herbicides, e.g., on
foliage, on cut stems, as an injection, or as a basal spray
directed to the bark of uncut stems. Repeat applications may
be necessary to reduce densities. Follow label and state
requirements. Managers should evaluate the specific
circumstances of each infestation, seek professional advice
and guidance if necessary, and use the herbicide in a manner
that is consistent with the product label and other state
requirements
Natural enemies: European white birch is especially
susceptible to damage caused by the bronze birch borer
(Agrilus anxius), a native beetle species.
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References:
1. USDA Forest Service, Forest Health Staff, Newtown
Square, PA. Invasive Plants
European White Birch (pdf) |
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