What are these buds of the tip shoot preparing to do in 1897? We can answer this question by going back just one year and seeing what the buds on the lower (or older) part of the shoot did in 1896. On that part (below B) the buds seem to have increased in size. Therefore, they must have grown larger last year. There were no leaves borne below these buds in 1896, but a cluster of leaves came out of each little bud in the spring. As these leaves expanded and grew, the little bud grew on; that is, each bud grew into a tiny branch, and when fall came each of these branches had a bud on its end to continue the growth in the year to come. What we took to be simple buds at 2, 3, 4, 5, 6, are, therefore, little branches.
But the strangest part of this wonderful little twig has not yet been seen,—the branches are of different sizes, and three of them (7, 8, 9) have so far outstripped the others that they seem to be of a different kind. It should be noticed, too, that the very lowermost bud (at 1) never grew at all, but remained perfectly dormant during the entire year 1896. It will be seen, then, that the dormant bud and the smallest branches are on the lower part of the shoot, and the three strong branches are at the very tip of the last year's growth.
If, now, we picture the twig as it looked in the fall of 1895, we shall see that it consisted of a single shoot, terminating at B. It had a large terminal bud (like those at 7, 8, 9, 10), and this bud pushed on into a branch in 1896, while three other buds near the tip did the same thing.
Fig. 216.—A two-year-old shoot from a young apple tree. Half size.
Why did some of these branches grow to be larger than others? "Simply because they were upon the strongest part of the shoot, or that part where the greatest growth naturally takes place," some one will answer. But this really does not answer the question, for we want to know why this part of the shoot is strongest. Probably the real reason is that there is more sunlight and more room on this outward or upward end. In 1897,—if this shoot had been spared—each of these four largest twigs (7, 8, 9, 10) would have done the same thing as the parent twig did in 1896: each would have pushed on from its end, and one or two or three other strong branches would probably have started from the strong side-buds near the tips, the very lowest buds would, no doubt, have remained perfectly inactive or dormant for lack of opportunity, and the intermediate buds would have made short branches like 2, 3, 4, 5, 6. In other words, the tree always tries to grow onward from its tips, and these tip shoots eventually become strong branches, unless some of them die in the struggle for existence. What, now, becomes of the little branches lower down?
Fig. 217. A three-year-old shoot and the fruit-spurs. Half size.
II.
From another apple tree I took the twig shown in [Fig. 217]. We see at once that it is very unlike the other one. It seems to be two years old, one year's growth extending from the base up to 7, and the last year's growth extending from 7 to 8; but we shall see upon looking closer that this is not so. The short branchlets at 3, 4, 5, 7 are very different from those in [Fig. 216]. They seem to be broken off. The fact is that the broken ends show were apples were borne in 1896. The branchlets that bore them, therefore, must have grown in 1895, while the main branch, from 1 to 7, grew in 1894. It is plain, from the looks of the buds, that the shoot from 7 to 8 grew last year, 1896.