Fences
Fences that could exclude beavers from large areas generally are cost prohibitive. Fences do not need to be high (just 24 to 30 inches), because beavers do not jump or climb well. Beavers will dig or crawl through openings, so the bottoms of fences should be tight against the ground or buried a few inches. Woven wire (4 by 4 inches) will deter beaver, but heavier gauge wire may be needed to protect a highly desirable resource. A 3-foot-high chain link fence (woodland-green, vinyl coated, 2-inch mesh, 0.095-inch core, 9 gauge) kept beavers from harming vegetation in a park. Similar fencing materials or rocks laid along banks can prevent beavers from undermining banks. Generally, a fence that crosses a small stream and extends 500 feet on either side will stop beavers from traveling along the stream.
Barriers can protect individual trees. Barriers do not have to be more than 30 inches high. Smooth surfaces work best, because if beavers can grasp the barrier's lips or flaps, they may pull or chew on them until they get to the tree. The best type of barrier depends on the desirability of the protected forage and the availability of alternative foods. Chicken wire and plastic tree wraps may deter beavers, but beavers can chew through these barriers easily if they really want to.