Girdling of fruit trees may be caused by rodents, sun-scald, winter injury, disease, or mechanical injuries such as those resulting from cultivating. If girdling is not repaired, the damaged trees die. Girdling is the result of destruction of the bark and living tissue that connect the roots of a tree with the part that is above the injury. Repair consists of reestablishing the connection. Girdled trees often can be saved by bridge grafting or by inarching. To be successful, either type of repair must be made soon after injury. If girdling injury is entirely above ground or if it has not seriously damaged the main roots, it can be repaired by bridge grafting. If the roots are damaged so badly that pieces cannot be grafted on them, the trees must be repaired by inarching.
There are three general divisions or kinds of graftage, between which, however, there are no decisive lines of separation: 1. Bud-grafting, or budding, in which a single bud is inserted under the bark on the surface of the wood of the stock. 2. Cion-grafting, or grafting proper, in which a detached twig, bearing one or more buds, is inserted into or on the stock. 3. Inarching, or grafting by approach, in which the cion remains attached to the parent plant until union takes place.
Budding is the operation of applying a single bud, bearing little or no wood, to the surface of the living wood of the stock. The bud is applied directly to the cambium layer of the stock. It is commonly inserted under the bark of the stock, but in flute-budding a piece of bark is entirely removed, and the bud is used to cover the wound. There is every gradation between budding and grafting proper.
Grafting is the operation of inserting a cion (or scion) — or a twig comprising one or more buds — into the stock, usually into an incision in the wood. It is variously divided or classified, but chiefly with reference to the position on the plant, and to the method in which the cion and stock are joined. In reference to position, there are four general classes: 1. Root-grafting, 2. Crown-grafting, 3. Stem-grafting, and 4. Top-grafting.
Veneer grafting makes no incision into old wood, and all wounded surfaces are completely covered by the matching of the cion and stock. It is not necessary, therefore, to wax over the wounds, as a rule. If used in the open, however, wax should be used. So far as the union of the parts is concerned, this is probably the most perfect form of grafting.
In making the resin and beeswax waxes, the materials are first broken up finely and melted together. When thoroughly melted, the liquid is poured into a pail or tub of cold water. It soon becomes hard enough to handle, and it is then pulled and worked until it becomes tough or “gets a grain,” at which stage it becomes the color of very light-colored manila paper. When wax is applied by hand, the hands must be well greased.
Grafting is one of the oldest of the arts of plant-craft. It is probable that the real art of grafting was held more or less as a professional or class secret in the ancient world, for the writers seem to have only the vaguest notion of its possibilities and limitations.