Good Riddles

Question: There was once three trees. The first tree did whatever the third tree did, and the third tree did what ever the second one does. What happens if tree number two gets cut down?

Question: When do you go at red, but stop at green?

Question: Why don't mountains catch colds?

Question: The first is a sign of something good,
the second says whereto;
the third is vulgar and mean,
the fourth is bound by a ring;
the fifth is the noble one.
Together they all drum.

What are they?

Question: A horse travels a certain distance each day. Strangely enough, two of its legs travel 30 miles each day and the other two legs travel nearly 31 miles. How is this situation possible?