Another strange fact should be well observed. The leaves of the maples and other deciduous trees are borne only on the present season's growth; but this is not the case in the pines, and kindred trees. If we trace back the growth of the past two or three years, we may find that there are as many leaves on the wood that is two years old as there are on the last season's growth; and in many cases we can find leaves on the part of the branch that is three years old. This means that the pine leaves or needles are two and sometimes three years old when they fall. The Fig. 232 shows the falling of the leaves from the different years' growth. The part of the branch between the tip and A is the last season's growth; between A and B it is two years old; the part between B and C is three years old. The part that grew four seasons ago--beyond C--has no leaves. [Illustration: _Fig. 233. Cone of white pine. It has shed its seeds. Half natural size._] The different seasons' growth is indicated not by distinct "rings" as in the case of deciduous trees, but by the branching. Each whorl of branches about a limb represents the end of a season's growth. A young pine tree, or the younger limbs of an old tree, shows this character very plainly. Do the leaves of the pines and of the other evergreen trees fall at the end of the growing season, as the leaves of most of the deciduous trees do? Or do they gradually become lifeless and fall at any season, from the force of the wind and other natural forces? Tie a large sheet of cloth in the top of some evergreen tree, in such a way as to form a receptacle to catch the leaves. Do you catch leaves in winter as well as in summer? Do you find leaves on the snow? As there are several different kinds of pines, we must picture carefully in our minds the foliage of the white pine, for it is different from that of any others. The leaves are soft and very slender, and from three to four inches long. The base of each cluster of leaves is at first surrounded by a small sheath. A scar is left when the leaves drop and these scars can often be seen on parts of the branches that are eight or ten years old. Do the leaves of other kinds of trees make a scar when they fall? The white pine cones, in which the seeds are borne, are conspicuous objects. They are five or six inches long and slightly curved. It will be interesting to find out whether the seeds ripen the same year in which they are formed. Perhaps a cone still containing seeds can be secured. Carefully tear it apart and see where the seeds are attached. Red squirrels sometimes eat the pine seeds. A white pine cone, which has shed its seeds, is shown in Fig. 233. [Illustration: _Fig. 234. Shoot of common pitch pine. One-half natural size._] This kind of pine is found widely scattered in New England, New York, and westward to Minnesota and Iowa and along the Alleghany Mountains as far south as Georgia; also in some parts of Canada. It is a valuable lumber tree.