“A number of observations like the following are familiar: Some foresters cut down a beech bearing on its trunk the date 1750. The same inscription was found again in the inner substance of the wood, but to reach it they had to cut through fifty-five layers on which no mark whatever appeared. If now, we add 55 to 1750 we obtain precisely the year when the tree was felled, or 1805. The inscription carved on the trunk in the year 1750 had passed through the bark and reached the layer of wood that was then outermost. Since that event fifty-five years had passed and new layers, exactly the same in number, had grown over the first. “Thus a tree is composed of a succession of woody sheaths, the outer ones enveloping the inner. The stem or trunk contains them all; the branches, according to their age, contain more or fewer. Each one represents a single year’s growth. The woody sheath of the present year occupies the exterior of the trunk, immediately under the bark; those of former years occupy the interior, and the nearer they are to the center the older they are. The layers of future years will come one at a time and take their places over preceding layers, so that what is now the outermost layer will in its turn be found embedded in the body of the trunk. “Of all these ligneous zones of unequal age the most important to-day is the outside one; its destruction would cause the death of the tree, since through it the nutritive juices of the earth reach the buds, leaves, and young branches. In their time the interior layers, one by one, when they formed the surface, rendered the same service to the buds of their day; but now that these buds have become branches the inner layers have only a secondary office, or even none at all. Those nearest the outside still have some aptness for work and help the layer of the year to carry the juices from the earth to the branches. As to the innermost ones, they have lost all activity; their wood is hard, dried up, encrusted with inert matter. In their decrepitude these interior layers are incapable of service in the work of vegetation; the most they can do is by the support of their firm woody structure to give solidity to the whole. Thus the tree’s activity decreases from the outside toward the center. On the surface are youth, vigor, labor; in the center old age, ruin, repose.” CHAPTER XV THE ROOT