Show PRACTICE OF BRIDGE GRAFTING OFTEN SAVES INJURED D' D AND DISEASED TREES t t t I 9 1 I How a Wound Is IB Repaired by Bridge Grafting Prepared by the United States Department Department Depart Deput- ment of or Agriculture Bridge grafting the use of scions or small limbs to connect the cambium cambium above and below a large wound or girdled strip may be practiced successfully successfully suc suc- on almost any kind of fruit tree that can be propagated readily by grafting Trees girdled by mice or rabbits suffering from mechanical InjurIes Injuries injuries In In- juries or from blight or other dIsease disease disease dis dIs- ease can be saved lu in many cases by bridge grafting The method also Is Is' useful when large areas of bark barJe have haye been killed by sun scald and other otherl In In- j juries rles Effective Grafting To be effective bridge grafting should be done clone one In the the spring before growth starts though sometimes It Itcan Itcan itcan can be pe e done after growth starts if dormant scions for the ilie purpose can be secured Prepare the wound In the tree by cutting away all dead tissue and thoroughly thoroughly thoroughly thor thor- cleansing the Injured parts If possible sterilize stE by washing with a solution of of mercury copper copper cop cop- per sulphate or some other antiseptic The irregular edges of th the bark above the girdle tract or wound should be cut back Into an even an-even even edge far tar enough from the wound to make certain that healthy cambium is under the bark barIc For the tile grafting select scions froni from wood of the previous seasons season's growth either branches which grew the he preceding preceding preceding pre pre- ceding season or water sprouts that are only a year rear old The scions should be be-a be than longer a which the than the sp the space ce Is to be bridged so they tIley will arch slightly over the central part of the wound Bevel the s scions lons at each ench end on the same ame side of the scion with a Ion long sloping cut so that the we wedge shaped ends thus formed will be relatively thin and nd permit penult their being thrust we well l under the bark without danger of separating it unduly from tt cambium cambium cam cam- blum at the points of Insertion The placing o of the scions will be he facilitated ed d if the bark at the margins of the wound is s slit silt for a short distance at fit atthe atthe the points where the ends are to be Insert Inserted d. d Importance of Uniting Cambium In pla th the scions it Is of the gr greatest Importance that the cambium of the scions which is exposed In the he sloping cuts at the ends be brought Into Intimate contact with the cambium cambium cambium cam cam- that lies under the bark at the tho margins of the wounded area The union of scion and tree can occur only where the tile cambium la layers ers of at the two come together The scions may be secured In their proper positions if need be by driving a small small nail through each ench end Into the trunk This will aid In drawing the cambium of scion and trunk closely together The operation Is completed by thoroughly thoroughly thoroughly thor thor- coveting covering the area occupied by bythe bythe the ends of the scions and the margins of the wound with Ith grafting wax strips of ot waxed cloth or 01 by some other means that adequately will prevent these parts from drying out Some Somo operators cover the entire wound scions and all with melted wax wax- Where the bridged portion is below or near the ilie ground many operators conserve moisture by covering r c the grafts with earth I Bridging From the Ground Where the wound Is so l large rge as IlS to tomake tomake tomake make ordinary bridge grafting Impossible Impossible impossible sible another method of bridging may maybe maybe maybe be used Two Two- year Two old ear trees are planted planter about the base of the Injured tree and their tops grafted into Its trunk above the girdled space which has first been cleaned as In tile tie other method As the tops of at th the small trees are too large xo tV manipulate readily in the manner described for scions shaped V-shaped vertical grooves grooves' ex ex- extendIng extending tending through the cambium are cut Just above the Ule wounded area In In the bark of the tree to be treated The tops of the small trees are re shaped to correspond with these grooves oves The two are then accurately fitted together in such a manner as to bring the cambium cambium cam cam- blum of one Into contact with that of the other Small nails may be driven through the tops of at the trees into the trunk to hold the parts firmly finnly cr er The wounds incident to joining the tops of the small trees to the trunk of the large one should be well covered with wax to prevent drying out Sometimes cord Is tied around the tile trunk to aid In holding the tops of the young joung trees In proper position |