WOUNDS 



245 



disappear when one or two short lengths of the tree are 

 removed, may be traced to such wounds on the root or collar 



(Fig. 141). Should the mycelium of 

 Agaricus me Ileus gain an entrance into 

 such root-wounds, decomposition pro- 

 ceeds much more rapidly, and the 

 lower part of the stem may become 

 perfectly rotten. 



When wood-ants (Formica hercu- 

 leana, or F. ligniperda) take possession 

 of these wounds, they frequently form 



FIG. 140. A beech which has 

 been severely barked by mice 

 above the collar. On the left 

 side a stripe of cortex has 

 been left. Numerous adven- 

 titious roots are seen breaking 

 through the uninjured cortex 

 above the wound. Natural 

 size. 



FIG. 141. The stool of a spruce that had formed 

 two stems. One of the stems, a, had been 

 removed in the thinnings, and from it decom- 

 position subsequently spread downwards into 

 the sound stem, b. At c c wounds have been 

 formed in the cortex during the dragging of 

 timber, and at e wound-rot has spread upwards 

 from a damaged root into the stem. One tenth 

 natural size. 



galleries which extend far up into the sound part of the stem, 

 and rapid decomposition succeeds their excavations. 



Intentionally or unintentionally, man is accountable for the 

 most varied forms of bark-wounds. Take, for example, the 



