Budding is sometimes employed the same as top-grafting for changing over the top of an old tree from one variety to another. The buds cannot be easily inserted in very old and stiff bark, but in all smooth and fresh bark they work readily. Sometimes old trees are severely pruned the year before the budding is to be done, in order to obtain young shoots in which to set the buds. In fruit-trees six or seven years old or less, budding is fully as advantageous as grafting. New varieties are also budded into old branches in order to hasten bearing for the purpose of testing the variety. Here budding has a distinct advantage over grafting, as it uses fewer buds, and the wood of new sorts is often scarce. Flute-Budding.--An occasional method of budding is that known under the general name of flute-budding. In this method the bud is not covered by the bark of the stock as in shield-budding. Fig. 68 illustrates it. A portion of bark is removed entirely from the stock, and a similar piece is fitted into its place. When the wound extends only part way about the stem, as in the illustration, the operation is sometimes known as veneer-budding. When it extends entirely around the stem it is called ring or annular-budding. Flute-budding is usually performed late in spring. It is best adapted to plants with very thick and heavy bark. The bud is tied and afterwards treated in essentially the same manner as in shield-budding. [Illustration: Fig. 68. Flute-budding.] A species of flute-budding in which a ring of bark is slipped down upon the tip of a shoot, which has been girdled for the purpose, is called whistle-budding or tubular-budding. _Grafting._--Grafting is divided in various ways, but chiefly with reference to the position of the union upon the plant and to the method in which the scion and stock are joined. In reference to position, there are four general classes: 1. Root-grafting, in which the stock is entirely a root. 2. Crown-grafting, which is performed upon the crown or collar of the plant just at the surface of the ground, an operation which is often confounded with root-grafting. 3. Stem-grafting, in which the cion is set on the trunk or body of the tree below the limbs, a method occasionally employed with young trees. 4. Top-grafting, or grafting in the branches of the tree. Any method of inserting the cion may be employed in these classes. The best classification, particularly for purposes of description, is that which considers methods of making the union. Some of these kinds of grafting are catalogued on page 66. For our purposes, we shall need to consider only the whip, saddle, splice, veneer, cleft and bark-grafting.