Home › When the Leaves Begin to Turn: September › When the Leaves Begin to Turn: September: Scarlet

When the Leaves Begin to Turn: September: Scarlet

Scarlet: Scarlet Oak, Sour-Gum, Black Haw, Sorrel Tree. Brown: American Elm, Buttonwood; White, Red, Blue, and Black Ashes. Many of the Oaks also show brown and reddish-brown (bronze) colorings in various shades and combinations. In the case of the evergreens the leaves or needles may not reach their full color until they are two years old or more. No doubt it's because it's their particular business to be evergreen, and so it takes them longer to manufacture all their greenness! But they take an additional precaution; they shed their leaves in "shifts," so to speak, somewhat as birds shed their feathers,1 (A Year in the Wonderland of Birds.) and for a similar reason -- because they can't go on doing business without them. In other words, they shed their leaves at intervals, just as other trees do, but they always retain enough to "carry on" and so they always look green.

HOW THE LEAVES GET READY TO FALL It is quite commonly supposed that the coloring of autumn leaves and their fall is due to frost. It is true that leaves may fall a little earlier than usual if there are early frosts, or the weather has been unusually dry, but you can see by consulting your Tree Diary from year to year that the leaves fall about the same time, regardless of wind or weather. The fact is the leaves "deliberately" prepare themselves for the return to Mother Earth, much as you may some day get ready for a winter journey back to the old home place by fastening down all your windows, turning off the water, and then stepping outside and locking the front door! Let me explain: In the leaves, as in little kitchens, is prepared the food for the entire tree. The "little people," the cells, who do this work, pass on the food to the tree, only keeping back enough to supply their own modest needs. The leaves may be said to be "closing the windows" when, with the approach of winter, they gradually stop absorbing the sunlight; for, near the upper surface of the leaf are certain cells, standing side by side like long rows of tall windows, and their special function is to let in the sunlight through the green curtains for the work of the household. While the "windows" are being closed the water-supply from the "mains" -- the innumerable little bundles of pipes that carry the water from the roots to all parts of the tree -- is being gradually lowered and finally entirely shut off, at the same time the "front door" is being closed and locked.

This is how the "doors" are closed: Quite a while before they fall the leaves grow a little wedge of cork between themselves and the parent tree, and before they finally drop, the openings in the twigs to which they are attached, and which would otherwise be left exposed to the invasion of injurious fungi, are carefully closed. The skin of the twig grows over them! III. THE SHAPES OF LEAVES An hour or so ago I asked a little girl neighbor who spends a good deal of time with me exploring the wonderland of our back yard, to bring me a leaf from a young Ash that grows near the garage. And when she came back to my summer desk on the broad and breezy porch where we sit together so often and talk things over, "Oh!" said I, "that isn't a leaf!" "Isn't a leaf? I'd like to know why! I picked it from the Ash Tree, just as you told me to. Another of your jokes, I suppose." (In this little back-yard-and-front-porch private school of ours we don't consider "getting educated" is such solemn business as many people seem to think!) "Yes, it is a kind of a joke -- a way of putting it -- but it's true, all the same. This does look exactly like a leaf but it's only one-seventh of a leaf; only one-ninth, maybe. Would you mind trying again?" She was off like a shot, and pretty soon back she came with what she called "a little branch with seven leaves on it." You see had taken the hint -- like most young people, her wits are very nimble -- and, looking more carefully, had seen that the leaves of this species of Ash are arranged in groups of seven -- occasionally nine -- each group on its little "branch." The separate leaves in such cases are called "leaflets," and the whole group put together is the leaf. The "branch" to which the leaflets are attached is the midrib of the leaf, but each leaflet also has its own midrib and all the other parts of the ordinary simple leaf. These grouped citizens of Treeland are called "compound" leaves because they are compounded of many leaves. I do believe we could write a whole book -- this little girl and you and I -- just about leaves!