Beaver damage, Castor canadensis

Fig. 422  Beaver damage to aspen.	Fig. 423  Beaver damage. Note wood chips left behind.

Distribution:  Throughout B.C. 

TREE SPECIES ATTACKED: All species can be damaged by beaver, especially trembling aspen, black cottonwood, balsam poplar, paper birch, and hybrid poplar.

WHAT TO LOOK FOR: Deep gnawing at base of main stem, often falling the tree.

SIGNS & SYMPTOMS: Beavers fall trees to supply their dam construction activities. They often flood forested areas for several years or decades. The remaining stumps are easily identified as beaver damage by their pencil-tip shape and teeth marks in the exposed wood. Wood shavings around the base of the stump may be found, along with trampled paths leading to water. Beavers clip seedlings, saplings, and branches from felled trees as food sources, especially in autumn. The clean, diagonal cut is diagnostic of beaver damage. Some branches may be cleanly stripped of bark. Broadleaf trees are preferred as food, especially smaller poplars and aspen, but almost any tree species of any size, including conifers, will be used, especially when located close to their lodge. 

DAMAGE: Tree and seedling mortality occurs from felling and flooding. Damage may be extensive near beaver dams and lodges. Beavers rely heavily on aspen for food and dam construction material; about 200 aspen trees would support one beaver for one year. Beavers can cause extensive mortality of saplings and trees up to 200 m from streams. Hybrid poplar plantations are know to incur heavy losses as whips and young trees are chewed off.

SIMILAR DAMAGE: Tree damage by beavers is highly diagnostic and the risk of confusion with any other damage should be low

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BC Ministry of Forests
Forest Practices Branch
P.O. Box 9513 Stn. Prov. Gov.
Victoria, BC
V8W 9C2

Section phone: (250) 387-8739
Section fax: (250) 387-2136

Last updated March 04, 2002