The beaver's habit of building dams for its uses often interferes with man's uses of the land when valuable timber is flooded or agricultural cropland suddenly winds up underwater. A beaver's main food supply is the inner bark layer of trees and shrubs called the cambium. Beavers cut down many trees and shrubs to get to this food supply as well as to supply themselves with construction materials for their dams. When beavers live close to people, they sometimes target valuable orchard or ornamental trees for their own use, much to the dismay of the human residents. From all this, it sounds like beavers are nothing but destructive pests but this is far from true.
Beavers are, by nature's measuring stick, probably one of the most beneficial of all animals.
When beavers dam up waterways, forming ponds, they actually create some of nature's most productive habitats. Amphibians, especially frogs, breed in the still waters which results in a large food supply for many other animals. Most trees in and around a beaver pond cannot stand the constant flooding of their root systems. As these weaken and die they are attacked by various species of insects which in turn attract insect-eating birds and other animals. The constant chewing and pruning of the surrounding vegetation by the resident beaver colony produces succulent and nutritious browse in the form of sprouts, utilized by the beavers themselves and other herbivores such as deer and rabbits.