Where all those hares came from, or where they went, or why they were traveling by night, we never knew.

That is a question for naturalists.

The next morning, when we went out to look for witches' brooms, there was not a hare in sight, except those that Addison had killed.
The witches' brooms were plentiful in the fir swamp along the stream; and as they were usually high up in the tree tops and not easily reached by climbing, we began to cut down such firs as had them.

At that time and in that remote place, a fir-tree was of no value whatever.
Firs are easy trees to fell, for the wood is very soft, but they are bad to climb or handle on account of the pitch.

We cut down about fifty trees that day, and left them as they fell, after getting the one or more witches' brooms in the top.