We have so much to do with human nature in February, in connection with the celebration of the birthdays of great men, it suggested for this chapter some comparison between the lives of trees and the lives of men; among other things, about how trees write their autobiographies, as great men have so often done, one way or another. Some of these tree autobiographies are quite sad, as in the case of the tree with a broken heart, and the one with a chapter in it about the dreadful fire and the year of the plague. On the other hand, in reading these life records, we shall find that trees have curious traits that are so much like those of human beings they make us smile. For example, we shall learn that at a certain average age for their families, they stop growing taller, and then, usually after they get to middle age, begin getting larger around the waist -- just as men are so apt to do if they don't keep up their gym work. We shall not only see that this is so but why it is so; and why trees lose the keen appetite of youth with advancing years. I'm sorry to say I shall also have to tell that all trees have a tendency to grow intolerant -- that's the forester's own word, "intolerant" -- as they grow in age, while others are just naturally born that way.