220 TIMBER AND SOME OF ITS DISEASES. [CHAP. 



other details must be passed over, however, and our 

 attention be confined to the fact that there are ample 

 chances for the spores of parasitic and other fungi to 

 fall on a surface admirably suited for their develop- 

 ment. The further fact must be insisted upon that 

 numerous fungus-spores do fall and develop upon 

 these wounds, and that by the time the exposed sur- 

 face is covered in (as in Fig. 31) the timber is frequently 

 already rotten, usually for some distance down into 

 its substance. In the event of fungi, such as have 

 been described above parasites and wound-parasites 

 gaining a hold on such wounds, the ravages of the 

 mycelium will continue after the occlusion is complete, 

 and I have seen scores of trees apparently sound and 

 whole when viewed from the exterior, the interior of 

 which is a mere mass of rottenness : when a heavy gale 

 at length blows them down, such trees are found to 

 be mere hollow shells, the ravages of the mycelium 

 having extended from the point of entry into every 

 part of the older timber. 



In a state of nature the processes above referred to 

 do not go on so smoothly and easily as just described, 

 and it will be profitable to glance at such a case as 

 the following. 



A fairly strong branch dies ofF, from any cause 

 whatever e.g. from being overshadowed by other 



