24 



SHADE TREES FOR NORTH CAROLINA. 



limit to the distance such a callus will grow, as circulation of sap must be 

 ^ maintained through it. After extending a certain distance beyond the 

 direct line of sap flow, its growth becomes slow and finally almost ceases, 

 being just sufficient to maintain a thin tissue of live inner bark on the 

 callus. In willows and in those trees which form pollards, even large 

 branches can be cut and sprouts will grow from the end of the stub, which 

 will soon heal over. Other trees when young, among them the cork, elm 

 and haekberry, can be pollarded to some extent. 



All exposed wood of a wound more than an inch in diameter shoiild be 

 painted with coal tar. Since there is danger of large branches splitting 

 and tearing the bark lose below the cut, it is better to cut them twice as 

 shown in fig. 5. An undercut made with a hatchet or ax lessens the 

 possibility of the bark being torn loose. 



Fig. 3. Fig. 4. 



Fig. 3. — In pruning large branches, especially on trees which are past their youth, 

 and whose powers of sprouting from cut branches is reduced, they should be pruned 

 so as to leave a living branch growing from the end of the stub. This branch will 

 usually maintain sufficient growth in the stub to cause the healing of the wound where 

 the large branch was removed. 



Fig. 4. — -Hollow snags should be cut close to the live branch from which they spring, 

 as at AB. If the hollow penetrates the live branch it should either be filled with cement 

 or with a wooden plug and painted, after the snag is removed. 



PRUNING FOR SHAPE. 



The crowns of newly planted trees frequently assume irregiilar shapes 

 after a year or two of growth. Such irregularities are to be corrected by 

 pruning the crown several years after permanent planting, when it is 

 possible to determine what shape is being formed. After pruning to 

 shape, the crown should be subsequently examined at intervals of three 

 or four years and tendencies towards irregularity remedied, when they 

 consist either in the prolongation or overgrowth of one or two branches, 

 or in the formation of a shape different from that of other trees in the 

 same line. All trees in the same line should have the same shape, or 



