Buzzard Swamp Beavers

I tried to walk at Buzzard Swamp near Marienville today but was stopped by a tree that had been felled across the access road by beavers. They had constructed a dam in a clearing some two hundred yards further on, but the tree is too large for beavers to drag that far, so maybe they plan to gnaw individual branches off. Alternatively, perhaps they had intended it for an abandoned dam they had started just off the left side of the road; even beavers can change their minds I suppose. Beavers are a common animal in the Allegheny forest, with ponds coming and going as the rodents die or are trapped for their fur.