2i6 TIMBER AND SOME OF ITS DISEASES [chap 



layers of wood and coitex with cambium between 

 them (Fig. 30) ; and it will be noticed that each year 

 the layer of wood extends a little further over the sur- 



FiG 30 ~The same in longitudim,! section P B^ and C as "before The four new 

 layers of wood formed durmg 1879-82 are aitificially separated from the preced- 

 ing by a str nger Une On the left side of the figure it will be noticed thit the 

 cambuim (and therefore the wood developed from, it) pr jected, a little further 

 over the cue end of the branch each year carrying the cortical layers (C^r) with 

 It At +, m both figures, there ib necessanly a depression m which ram-water, 

 S.C , IS apt to lodge, and this is a particularly dangerous place, since fungus 

 spores may here settle and develop 



face of the wood of the wound, and towards the 

 centre of the cut branch , and in course of time, 



