240 PRACTICAL TREE REPAIR 



heartwood, the omnipresent white heart rot being 

 foremost among them. The honey mushroom 

 often infests the roots of the tree. Several bark 

 rots and cankers are ever ready to complete the 

 destruction of a weakened patch of the bark. Its 

 insect enemies are no less numerous. Round- 

 and flat-headed borers attack its heartwood and 

 sapwood. Bark beetles girdle and kill the trees. 

 The apple is one of the commonest and one of 

 the most difficult subjects to come under the care 

 of the tree repairer. There are several reasons 

 for that fact. In the first place, the apple is nat- 

 urally very subject to the attacks of fungi and 

 borers, as has been shown by the above enumera- 

 tion of a few of Its principal enemies. And it 

 seems as if man had made every effort to help the 

 fungi get at the apple's heartwood. When the 

 young tree is planted too large a number of 

 branches are permitted to grow out from the 

 trunk, and they are altogether too close together. 

 When the tree reaches maturity each of these 

 limbs has become long and rambling, with a shock 

 of branches and twigs at its end. To the lowest 

 tier of these limbs one of two things usually hap- 

 pens. The limb may be killed by bark canker or 

 blight, or by being overshaded as the trees in the 

 orchard grow together. In the course of time 

 the owner removes the dead limb. Its butt is 

 often so closely squeezed in between other limbs 



