|
THE GREEN MAGICIAN, THE CONGRESSMEN, AND THE HIGH-SCHOOL GIRLS If trees really are the intelligent creatures they are represented to be by the poets, they must do their thinking, like the rest of us, in their "tops"; that is to say, up among the leaves where the Green Magician, scientifically known as "chlorophyll," lives. How the G. M. must have rejoiced, then, when he heard of the passage of the Weeks Act! (The Weeks Act was passed by Congress in 1991. It gives the government authority to buy lands on the watersheds of eastern streams, so that our rivers may be protected against floods and erosion.). And how do you suppose they feel when they see members of our Great Army of the Common Good in the public schools doing such things as the planting of trees on the Antietam watershed by the high-school girls of Reading. Pennsylvania, from which I take this example of what schools are doing, more or less, all over the country and of which Gifford Pinchot, former head of the National Forest Service and largely responsible for its efficiency, is now governor, is a splendid example to the rest of the nation. A TWO-HUNDRED-GALLON THIRST! Goodness knows, if anybody ought to be interested in watersheds and a good reliable supply of water, it would be this same Green Magician. He simply must have water or he can't do his magic at all. Do you know how much, water an Oak, just a medium-sized Oak, will drink in a day? About 200 gallons! (Hardwoods require from four to six times as much water as the Pines and other cone-bearing trees. The hard and the soft woods also differ among themselves in this respect. Red or Norway Pine grows on dry, gravelly soils where the White Pine would die. Walnuts, Maples, and Beeches do best on deep, rich, moist soil.) This water is to meet the needs of the green necromancer in making the magic potion known as sap. The water of the soil, together with the useful minerals it contains, is absorbed by the tree roots and is then drawn up to the leaves--actually flows up-hill, in response to some mysterious power, not yet clearly understood--and is there combined with the air breathed in by the leaves. The tree retains the carbon of the air and makes it into sugar and starch, then puts the sugar and starch into the sap, which is the life-blood of the tree. Most of the oxygen it gives back to us and to our fellow animals, only retaining enough to meet its own modest requirements. HOW TREES EARN THEIR LIVINGS BY THE SWEAT OF THEIR BROWS When growth begins in the spring and the fresh leaves and twigs appear, there is an unusual demand for water. The trees "foreseeing," so to speak, this extra demand, make it a practice in the fall, with the coming of the autumn rains, and in the spring, with the melting of the snows, to store up an extra supply. Like the camel, the tree has special water reservoirs, certain cells set apart for this very purpose. Leathery-leaved trees, such as the Oaks, and plants in dry regions where it is a long time between rains, have also little storage-tanks in their leaves--enlarged cells immediately under the surface. With this surplus on hand in the spring and the newly awakened and enthusiastic young roots--the root-hairs--pumping up more than the clever gentleman in the green coat can handle, the trees are unable to return this water to the air in the usual form, as invisible vapor, and it falls in drops from the earliest buds and, later on, from the leaves. So, like the farmer on whose land it stands, a tree may be said to earn its living by the sweat of its brow. You remember that, as we learned in February, another amusing reminder of the ways of humanity, in the lives of our tree friends, is that when they get on in years they stop growing taller and begin putting on extra girth. The reason is this: Height growth is limited by the fact that their mysterious elevator system, remarkably efficient as it is, cannot hoist the soil water more than a certain distance above the ground; so the limit of its "hoist" is the limit of its height. This distance differs with different species of trees. Most kinds of trees do the most of their growing in the spring. LITTLE BUD HAS A "SWEET TOOTH," TOO! The reason you can't get much sap from a Maple-Sugar Tree if you wait too late in the spring is that, by that time, the tree has so many youngsters of its own with a "sweet tooth," above say, that they drink it up, as it flows along, and there is comparatively little left for outsiders. These "youngsters" are the bursting buds and the green leaves. And you weren't surprised, were you, to hear in the February chapter that the youngsters of Leafland have appetites out of all proportion to their size? for that reason the Green Magician has to work all the harder to supply them. Or, to put it in the language of the learned: "In young leaves the assimilative capacity in proportion to the chlorophyll is greater than in old leaves." The needle-like leaves of the evergreens do not reach their full color until they are two years old or more. It being their special business to be ever green, it takes them longer to get all their green on, I suppose! |
|
Return to A Year in the Wonderland of Trees