III. The Storm Ploughs of the Wind
TWO KINDS OF WOODEN PLOUGHS
They use wooden ploughs, these winds, just as primitive man did, and as primitive peoples do now; but not quite in the same way, and the ploughing they do is much better. For man's wooden plough is a crooked stick made from the branches of a tree while the winds use the whole tree—roots and all, and both on mountainsides and on level lands the amount of ploughing they do is immense.
Almost all forests are liable to occasional hurricanes which lay the trees over thousands of acres in one immense swath. A large number of these trees, owing to their strong trunks, do not break off but uproot, lifting great sheets of earth. Soon, by the action of its own weight and the elements, this soil falls back. The depth to which this natural ploughing is done depends, of course, on the character of the tree, but as it is the older and larger trees that are most likely to be overturned, since they spread more surface to the wind, the ploughing is much deeper than men do with ordinary ploughs.
The result is that new unused soil is constantly being brought to the surface; and not only this, but air is introduced into the soil far below the point reached by ordinary ploughing. The soil needs air just as we do; for the air hurries the decay of the soil and its preparation for the uses of the plant. The immediate purpose of ploughing is to loosen the soil so that the roots of the plants can get their food and air more easily. It also helps to keep the fields fertile by exposing the lower soil to more rapid decay.
But here's the trouble: While the ordinary plough introduces air into the soil for a few inches from the surface, the subsoil, which is very important to the prosperity of the plant, is practically left out of it, so far as getting needed fresh air is concerned. The long roots of the trees that, among other things opened for it channels to the air, are gone. The burrowing animals that used to loosen up the earth, man has driven away. More than that, the foot of the plough which has to press heavily on the subsoil in order to turn the furrow, smears and compacts the earth into a hard layer, which shuts out the air, and also—to a certain extent—the water from the lower levels.
HOW THE SOIL GETS ITS BREATH