Placing wire cages around trees are good ways to protect them. The cages can be made from hardware cloth or heavy welded wire fencing. The cages need to be put up around the trees at least 3′ high but 4′ is better if there may be heavy snows. Leave about 4′ between the tree and the wire when you put it around the trunk. Chicken wire is not as good around large trees unless it is used in multiple layers. Chicken wire is useful to put around a group of small trees or shrubs, but you need to anchor it or the beaver will crush it down walking over it.
Fencing off groups of trees or shrubs with a low fence will protect them. Since beavers don't like being separated from the water, your fence does not have to be totally around the area, but may be on the side toward the water and/or part way up the sides. Make it a sturdy fence tight to the ground to prevent walking over or under and crushing the fence.
An electrified wire strung 4-6″ off the ground is also an effective deterrent.
