162 THE CULTIVATED EVERGREENS 



attacks, it can be accepted as a general fact that the organism 

 is present not only in the tissue which actually shows the 

 disease to the naked eye, but also for some distance beyond this 

 area in all directions. A certain amount of apparently healthy 

 tissue should always be removed, therefore, in order to ensure 

 the complete eradication of the fungus. All cut surfaces should 

 then be sterilized and protected from drying out and from the 

 attacks of other organisms. This will involve the examination 

 of the treated parts from time to time so that any defects may 

 be remedied immediately. A neglect of this precaution may 

 nullify all previous work done. Finally, all the treated portions 

 must be left in the most favorable condition for rapid healing. 



Removal of branches. 



When small branches or twigs are the parts diseased, it 

 will be the simplest procedure to remove them entirely. In 

 doing this, no stubs should be left, for they are both unsightly 

 and a source of danger to the future health of the tree. Diseased 

 branches should always be cut off with a wide-toothed saw 

 flush at the point where they join healthy ones, care being 

 taken not to strip the bark below. The surface of the wound 

 should be trimmed with a sharp knife and the scar pointed 

 above and below. Following the knife, the exposed sapwood 

 and bark should be covered immediately with a coating of 

 good shellac. This will serve the double purpose of preventing 

 the drying out of these living tissues and also the excessive 

 exudation of resin which takes place from the wood of some 

 coniferous trees. (The resin secreted by such trees is sometimes 

 smeared over the cut surfaces to take the place of other dres- 

 sings; but, while it serves well as a protective covering, it 

 usually runs down the bark of the tree, leaving unsightly white 

 streaks.) The exposed heartwood should now be sterilized 



