"Just see how damp the ground is under these dead leaves!" said Susie as she pushed them back from a little violet that she was trying to pick with a long stem. "Poor little flowers! How do they ever get through all these leaves? It would be so much easier for them if it was just green grass." [Illustration: The bridge. ] "But then there wouldn't be any flowers," said Mr. Leonard, "or at least they would be very different." [Illustration: HICKORY OAK WILLOW BUTTER-NUT MAPLE WALNUT (leaves)] "It's the leaves that make the soil so rich," said Frank, digging into the ground with a stick. "See how they are mixed all through it!" "Do you know the names of all these trees?" asked Uncle Robert. "I do," said Frank. "I can tell every tree in the wood." "How?" asked Uncle Robert. "By the leaves is the easiest way," said Frank, "but I know some trees by the bark." "I can tell them by the leaves," said Donald. "Try me." So as Uncle Robert pointed to them Donald called them all by name. There were oaks and maples, hickories, walnuts, and butternuts, and close to the creek the overhanging willows. "Can you tell a tree by its shape when you look at it from a distance?" asked Uncle Robert. "I can tell the willows and poplars," said Frank, "and maples, too." "The trees in the pasture have a different shape from those in the woods," said Uncle Robert. "I mean trees of the same kind. How do you explain that?" "Why, the trees in the pasture have a chance to spread out," said Donald. "There isn't so much room in here." "But these trees are taller," said Frank, "and they are straighter, too." "Can you tell the direction of the winds that blow the strongest and longest by the shape of the trees?" asked Uncle Robert. "I never thought of that," said Frank. "The wind doesn't blow in the woods," said Donald. "When we get out into the pasture we'll notice the trees there," said Mr. Leonard. "Isn't this a tiny tree?" said Susie. "I wonder what it is." "That's an oak," said Frank. "The leaves tell that." "Oaks grow from acorns," said Donald. "I'm going to dig this up and see if it grows like the seeds in the garden." "What a long root it has!" said Susie as Donald dug about it. "Don't take it out, Don. Put the dirt back and let it grow to be a tree." [Illustration: Oak sprout.] "How long will it be before it gets as big as these trees, uncle?" asked Frank. "A great many years. Perhaps your father can tell about how old some of these trees are." "I have cut some," said Mr. Leonard, "that were about a hundred years old." "Why, father," exclaimed Susie, "how could you tell?" "Do you know how the end of a log looks when it is sawed off straight?" "I do," said Frank. "There are light and dark rings in it." "Well," was the reply, "one of these rings grows every year." "So if you count the rings you can tell how old the tree is," said Donald. "Isn't that great!" [Illustration: End of a log.]