DBFB0T8 AND UNSOUNDNESS. 



5. Covered sections of pruned branches. 



37 



However carefully a branch may be pruned off, and even if the 

 surface of section is painted over with some antiseptic substance, 

 there is never any real union between that surface and the new 

 wood that forms over it. If the branch is at all large, saprophytic 

 fungi never fail to enter the section and engender rot {see Fig. 6.) 



Fi&. e. 



Section showing remit of the most careful 

 priming. (After Boppe). 



In any case no portion of the section can be left in any kind of 

 small stuff into which the wood may be converted. 



6. Occluded broken branch. 



Such branches can of course never form any union with the en- 

 closing rings of wood. The end of such a branch, having for a 

 longer or shorter time after death been exposed to the air and 

 atmospheric moisture, is invariably more or less decayed before 

 occlusion takes place. Hence the tissues of the branch itself and 

 those surrounding it are always in a more or less advanced stage 



