thanks

one can see plenty signs of their activity. They do fall trees. However, in this place they don't need to build a dam. The river is regulated and runs between earthen work. The high banks are perfect for them - they simply start digging below the water surface, and then within the earthen work dig up to create their "homes". Smart animals. So the trees they do fall are thin - the beavers are after the bark and thin branches, a delicacy for them. Besides, since this is within city limits, if there's any danger to humans, the city service cut down tree that can potentially harm people