The beaver is the largest rodent found in North America. An adult beaver can weigh up to 60 lbs, but on average they weigh about 35-40 lbs. Including their trademark flat tail used as a rudder, construction tool and communication device, the adults are about 30 inches long and a foot high. When standing on its hind legs an adult beaver can reach almost 3 feet. Beavers are well adapted to the aquatic habitat that, for the most part, they design and maintain. A beaver can submerge for as much as 15 minutes, during which time it can carry tree limbs under water in it's incisor teeth thanks to a special flap of skin designed to prevent water from being swallowed.
Beavers live in and around water and constantly modify streams by building dams and impounding water flows to create ponds, although they will also live in large rivers and lakes without building dams at all. The beaver impoundment provides a rich environment for many animal and plant species. There is a regular cycle in land changes created by the beavers, providing different values at each stage. The largest beaver impoundment in North America is 2,160 feet long located at Rocky Mountain National Park in Colorado.
The two most common problems caused by beavers are flooding that results from dam-building and the damage or destruction of trees used for building material. Flooding can suddenly become a crisis if beaver dams are not monitored properly and unusually heavy rains inundate an area. Occasionally, bank dens dug by beavers contribute to erosion or undermining of earthen dams, a problem that also occurs where muskrats are active. Damaged trees in urban or suburban areas is likely to be noticed before it becomes critical but perhaps not before one or more valuable trees have been lost.
Tolerance recognizing that beavers play an important role in establishing and maintaining wetlands that provide critical environmental functions is a key to living with them. Among other things beaver impoundments provide a habitat for other animals, provide refuge for sensitive plant species, improve water quality by acting as a settling basin and provide flood control by slowing water movement. Beavers are superb engineers, but still no competition for humans. This means that no matter what engineering problems the beavers may cause, humans can counter with solutions of our own that beavers cannot overcome. Where flooding or potential flooding from beaver dams is an issue, it is possible to install a variety of devices, variously called beaver "baffles" or " levelers" , that can control water level without the removal or the destruction of the Beaver.
Either homemade or commercially available tree guards can prevent a beaver damage to trees, especially where small ornamental or specimen trees need to be protected. Simple cylinders of galvanized welded 2" x 2" wire placed out from the trunk and standing about three feet can be used to cage trees. cylinders around larger trees may require stacking, and mulching within the cylinder is a good idea to keep weeds from becoming a problem.