Beavers have webbed hind legs that act like as a paddle when they swim through water. They have a large flat tail that helps them steer through water. Their tail is used for other things for example...
A beaver's size [L] is 80cm.-120cm.
Yes, beavers can move their tails. They use them while swimming and can also use their tails to help build their dams.
Beavers are nocturnal.
He doesn't move the whole tree, they move the branches