To prevent conflicts or remedy existing problems:
Choose and place plants carefully.
Plant areas with Sitka spruce, elderberry, cascara, osoberry (Indian plum), ninebark, and twinberry, because they are not the beavers’ preferred food plants. Densely plant aspen, cottonwood, willow, spirea (hardhack), and red-twig dogwood because, once their roots are well established the upper parts of the plants often resprout after being eaten. Planting preferred plants away from known beaver trails will limit losses.
Note: Beavers do use plants as construction materials that they might not eat.
Install barriers.
The trunks of individual large trees can be loosely wrapped with 3 foot high, galvanized welded wire fencing, hardware cloth, or multiple layers of chicken wire (Fig. 6). Barriers can be painted to make them less noticeable. Welded wire fencing coated with green vinyl that helps the fencing blend in is also available.
Lengths of corrugated plastic drainpipe can be attached around the trunks of narrow-diameter trees.
Note: Dark-colored pipe can burn trunks in full sun; wider diameter pipe or pipe with holes in it may prevent overheating problems.
Painting tree trunks with a sand and paint mix (2/3 cup masonry grade sand per quart of latex paint) has proven somewhat effective at protecting trees from beaver damage. The animals presumably don’t like the gritty texture.
Note: Preventing access to food sources may force beavers to eat other nearby plants, including roses and other ornamentals.
Figure 6. Various barriers can be used to protect plants from beaver damage. All plants should be protected to at least 3 feet above ground—or the snow line—and inspected regularly.
(Drawings by Jenifer Rees.)
Surround groups of trees and shrubs with 3-foot high barriers made of galvanized, welded wire fencing or other sturdy material (Fig. 7). (A beaver’s weight will pull down chicken wire and similar lightweight material.) Stake the barriers to prevent beavers from pushing them to the side or entering from underneath. An electric fence with two hot wires suspended 8 and 12 inches off the ground is also effective at protecting groups of plants.
Figure 7. Groups of plants can be protected from beaver damage by surrounding them with wire fencing.
Protect large areas that border beaver habitat by installing 4-foot high field fencing. Keep the bottom of the fence flush to the ground, or include an 18-inch wide skirt on the beaver side of the fence, to prevent beavers from entering underneath.
Groups of plants can be protected from beaver damage by surrounding them with wire fencing.
Apply repellents.
Commercial taste and odor repellents have provided mixed results, perhaps because they need to be reapplied often, particularly in moist weather. Taste and odor repellents are most effective when applied at the first sign of damage, when other food is available, and during the dry season. Two repellents that have had some success are Big Game Repellent® and Plant-skydd®. (See “Repellents” in Deer for additional information.)
Control the height of water behind a beaver dam to prevent flooding.
It may be possible to make a small change in the depth of a beaver pond by installing a flow device at the intended depth, extending upstream and downstream of the dam. This keeps the rise in the water level at a minimum by using one or more plastic pipes to continually drain the pond area (see “Flexible Leveler” below. Click to enlarge). For leveling systems to work properly, you will have to have at least 3 feet of water in the pond area for the beaver to stay.
The flow device can be constructed from plastic pipe measuring 4 to 12 inches in diameter, depending on the volume of water in the stream. The end extending upstream from the dam must be baffled to prevent beavers from damming or blocking the pipe.
Flexible Leveler
Click to enlarge
Prevent beavers from plugging culverts.
To a beaver, a culvert probably looks like a hole in an otherwise fine dam. When they plug the hole, a flooded road can result. However, V-shaped, semicircular, or trapezoidal fences of woven wire mesh can prevent culverts from being plugged (see “Beaver Deceiver” below. Click to enlarge.). Large flow-control devices that include a solid framework can be covered and used as a deck or wildlife viewing spot.
Note: Installation of flow control devices is complicated and generally requires a permit (see “Legal Status”).
Beaver Deceiver
Click to enlarge
Dam removal.
It is pointless to destroy a beaver dam because beavers (frequently many at one time) often begin rebuilding them immediately after they are removed. Furthermore, it may be illegal to remove a beaver dam without a permit (see “Legal Status”).
