The log cabin Democrat., 1916-05-04

Grafted Into the Trunk of the OIt Prepared by the United States Depart
 ment of Agrculture)
 Bridge grating, the use of scions or small limbs to connect the cambium above and below large wound or gir- dled strip, may be practiced success fully on almost any kind of fruit tree that can be propagated readily by grating. It is used more often with the apple than any other fruit, but pear trees often are treated in this way, especially in certain sections. There seems to be no reason why the method should not also be successful on plums and cherries, according to Farmers Bulletin 710, Bridge Graft ing of Fruit Trees" just issued by the department Peaches, however, graft less readily and there may be some question as to the usefulness of the method in the case of this fruit. While seldom used on shade or other orna- mental trees, the author, w. F. Fletcher, writes that this method of grating probably would prove success full in overcoming certain types of in- juries to them.
 Mechanical injuries which may be remedied are usually inflicted by ami mals, by burrowing insects, or by i'm plements carelessly used. Various diseases, such as pear blight, also cause local injuries which may call for bridge grating. The trunks of pear trees are not infrequently completely girdled and killed by pear blight. Bridge grating, if done in time, how ever, may save the tree.
 The method also is useful when large areas of bark have been killed by sun scald or other troubles. The au- thor of the bulletin points out, how ever, that protection of trees against rabbits and mice and disease is, of course, better than having to bridge graft to overcome damage.
 Methods of Bridge Grating.
 To be effective, bridge grating should be done in the spring before growth starts, though sometimes it can be done after growth starts if dormant scions for the purpose can be secured.
 Prepare the wound in the tree by cutting away all dead tissue and thor oughly cleansing the injured parts. If possible, sterilize by washing with solution of bichloride of mercury, cop per sulphate, or some other antiseptic. The irregular edges of the bark above the girdled tract or wound should be cut back into an even edge, far enough from the wound to make certain that healthy cambium is under the bark.
 For the grating, select scions from wood of the previous seasons growth, either branches which grew the pre- ceding season or water sprouts that are only year old, The scions should be little longer than the space which Is to be bridged, so they will arch slightly over the central part of the wound.
 Bevel the scions at each end on the same side of the scion with long, sloping cut so that the wedge-shaped ends thus formed will be relatively thin and permit their being thrust we'll under the bark without danger of separating it unduly from the cambium at the points of insertion. The plac- ing of the scions will be facilitated if the bark at the margins of the wound is slit for a short distance at the points where the ends are to be inserted.
 Importance of Uniting Cambium.
 In placing the scions it is of the greatest importance that the cambium of the scions which is exposed in the sloping cuts at the ends be brought into intimate contact with the cam blum that lies under the bark at the margins of the wounded area. The union of scion and tree can occur only where the cambum layers of the two come together The scions may be se- cured in their proper positions, if need be, by driving a small nail through each end into the trunk. This will aid in drawing the cambium of scion and trunk closely together
 The operation is completed by thor oughly covering the area occupied by the ends of the scions and the mar gins of the wound with grating wax strips of waxed cloth, or by some other means that adequately will pre- vent these parts from drying out