236 DISEASES OF TREES 



the forms of decay in wounds which are induced by parasites, 

 there are other forms of decomposition in wood in which parasitic 

 fungi take no part. It is rather to the saprophytic fungi, in 

 conjunction with atmospheric influences, that a variety of forms 

 of decay in wood are to be ascribed. In the meantime I propose 

 to apply the collective term "Wound-rot" to those various 

 forms of decay which have not yet been explained. 1 



The many forms of decomposition which are embraced under 

 this term have not yet been subjected to scientific investigation. 

 Should a large portion of the stem become functionless and die, 

 saprophytic fungi belonging to the Hymenomycetes or Ascomycetes 

 induce decomposition, especially when their growth is stimulated 

 by the unrestricted entrance of rain-water. This state of things 

 exists in the case of snags destitute of buds, the stools of felled 

 trees, trees that have lost large patches of bark by game, 

 sun-scorching, &c., and which soon die to a considerable depth 

 owing to the effects of drought. When water and air find 

 easy access to a t wound, as in the case of root-wounds, and 

 branch-wounds that have not been tarred, decomposition spreads 

 fairly rapidly in the direction followed by the water in the 

 elements, although this wound-rot certainly does not progress 

 nearly so rapidly as that which is due to parasitic fungi. The 

 so-called false duramen of the beech always proceeds from a 

 wound, and not only are all the vessels filled with tyloses, but 

 the tannin is also so changed as to produce brownness in 

 the heart-wood. Saprophytic fungi slowly advance from the 

 wounds, and produce decomposition in the false duramen. The 

 sooner a wound is closed, either artificially or naturally, the 

 better for the tree. When air and water are excluded, wound- 

 rot advances so slowly as only to reach a depth of half an inch 

 in a century, as is shown by the occluded branch-wound of an 

 oak in my collection. 



The treatment of wounds follows from what has been said. 

 Two objects have to be kept in view first, the process of 

 healing, and, secondly, protection against wound-diseases, both 

 infectious and non-infectious. 



The most perfect form of healing namely, the re-clothing of 

 the wound with a new cortex can only be looked for when the 

 1 Zersetzungserscheimingen, &c., p. 63. 



