Tree Protection Strategies

Wire Mesh Cages or Fencing

Installing wire cages around the trunk of a single tree or wire fencing around multiple smaller trees and shrubs can effectively deter beavers if done properly.

Materials:

Four-foot tall galvanized garden fencing works well, or any material that meets the following specifications:

• Reasonably heavy (e.g., 6 gauge)
• At least 3 feet in height
• A mesh size of 6x6 inches or smaller (2x4 inches is ideal).

Instructions:

Arrange welded mesh wire in a circle around the trunk(s) or stem(s) you want to protect, securely fastening the ends together. If needed, cut the bottom of the fence to fit sloping ground or protect prominent roots from chewing.

Ensure the mesh wire is heavy enough to prevent beavers from chewing through it and flexible enough for this application.

Install sturdy stakes or supports around the wire cage and attach the fencing to them. This will prevent beavers from pushing the fencing against the tree trunk and chewing it. Steel T-posts work well for this purpose. Always call 811 for locates before digging or pounding anything into the ground.

Leave a 6-to-12 inch space between the wire cage and the tree trunk to prevent damage if beavers try to chew between the wires and to give the tree room to grow.

Important Notes About Using Beaver Fencing:

• Beavers are strong animals, so select materials that can withstand a 60-pound animal putting its front legs on them.

• Check your wire barriers every year to ensure they do not inhibit tree growth. Barriers can be painted to make them less noticeable. Welded wire fencing coated with green vinyl is also available to help it blend in. Avoid letting your tree trunk grow into the wire, as this can girdle the tree and kill it.

Electric Fencing

In areas where large sections of vegetation need protection from beavers, electric fencing has proven to be an effective solution. This can be relatively low-cost and involves two bare wires, steel T-posts, plastic insulators, and a small solar charger. The system should include:

• At least two electrical wires, set at 6 inches and 10 inches from the ground.

• A grounding system for the fence charger.

• Vegetation maintenance under and around the fence.

Important Notes About Using Electric Fencing:

• Electric fences become ineffective if vegetation grows around them or if branches fall on them. In dry seasons, this can also create a fire hazard. Inspect electric fencing periodically to ensure it has not shorted out.

• Electric fencing is less noticeable than a large fence enclosure, but consider safety issues if you have pets or small children who are unaccustomed to electric fences.

Sand/Paint Mixture

In areas where trees need protection from gnawing or felling, but where installing wire cages is not feasible, abrasive paint can serve as a deterrent. This method requires minimal materials and labor but is only effective on stems that are at least 6 inches in diameter (beavers will not be deterred if they can chew through the stem in one bite).

Instructions:

• Mix 8 ounces of fine dry sand (30-mil, 70-mil, or masonry sand) with 1 quart of interior latex paint (you can match the color to the tree trunk if desired.
• Apply the paint to the bottom 3 to 4 feet of the tree trunk and any exposed roots you want to protect.

Important Notes About Using Abrasive Paint:

• Mix the paint in small batches right before use.
• Use interior latex paint and check for environmental safety before purchasing. Some exterior latex paints contain heavy metals to protect color from fading, which can leach into nearby streams and harm water quality. Avoid such paints.
• As the painted tree grows, areas of unprotected bark will emerge. Check the trees annually and add paint when you notice significant areas of unprotected bark.

Beaver Buffers

Another way to keep beavers from entering your yard and damaging your trees and shrubs is to plant and maintain a "beaver buffer" between the stream and your landscaped area. A beaver buffer should consist of a mix of native riparian plants that beavers prefer to eat and those that are unpalatable to them. The wider the beaver buffer, the less likely beavers are to come into your landscaping or orchards looking for food.

Native Riparian Plants that are Unpalatable to Beavers: Native species that thrive in riparian areas and are typically avoided by beavers include tall Oregon grape, Pacific ninebark, red elderberry, cascara, osoberry, clustered wild rose, Douglas spiraea, and twinberry.

Native Riparian Plants Preferred by Beavers: Native species that beavers prefer to eat include willow, red-osier dogwood, Oregon ash, bigleaf maple, and black cottonwood. These species have coevolved with beavers and will continue to re-sprout even after repeated cutting. However, young plantings will need temporary protection until they are established if beavers are already present in the area.

Important Notes About Beaver Buffers:

• Look for these species at local native plant sales and plant them in the fall or winter to take advantage of natural rainfall for establishment.

• The City of Salem offers some of the above species through our free tree program for streamside residents.

• Planting unpalatable plants can improve overall habitat while deterring beaver foraging in a given area. However, planting only unpalatable plants may cause beavers to venture further from the water in search of more palatable vegetation.

• Dense patches of native plants that beavers prefer along the waterline can help focus their foraging attention away from other vegetation. Mixing in some unpalatable plants ensures canopy cover over the stream and banks, even after beavers eat all their preferred vegetation.