i 9 4 DISEASES OF TREES 



ash-constituents of the wall impart to it a finely granulated 

 appearance. 



The fungus is only in a position to produce sporophores when 

 it has developed luxuriantly in the interior of the tree. In that 

 case the mycelium pushes its way outwards at a place where the 

 base of a dead branch opens a passage through the alburnum. 

 At such a place the sporophores are produced, and should these 

 be forcibly removed a number of new ones are, as a rule, formed 

 in a short time. 



It is thus seen that nothing is gained by removing the 

 sporophores, but trees infested by the fungus should always be 

 removed in the thinnings and other fellings. We thus remove 

 the danger of infection, and utilize the trees before they are 

 rendered entirely valueless by the advancing decomposition. It 

 frequently happens that, although fungi are visible on the upper 

 region of the tree, the disease has not extended down to the 

 lower and valuable part of the stem, so that, after cutting off the 

 upper portion, some good useful timber is available. If one 

 waits till the final felling before removing the fungus-infested 

 trees, all that one gets is very worthless rotten wood. Of course 

 a stop must also be put to pilferers breaking or sawing off 

 green branches, as this practice increases the probabilities of 

 infection. Old branches that have died naturally cannot be 

 attacked by the fungus. 



This disease is most prevalent in the neighbourhood of towns 

 and villages, where the pilfering of branches is common, and in 

 woods that are much exposed to the wind, and where, conse- 

 quently, branches are frequently broken off. 



POLYPORUS HARTIGII (ALL.) 



When I first described this parasite of the silver fir and spruce, 

 I made the remark, " Whether this is a new species distinct from 

 Polyporus fulvus can only be decided by a careful study of the 

 allied species of this genus. In the meantime it may pass 

 under the name of P. fulvus'' 1 Since then it has been recog- 

 nized as an undoubtedly new species, and has been introduced 

 into the literature of the subject by Herr Allaschen under the 

 name P. Hartigii. 



1 R. Hartig, Die Zersetsungserscheinungen des Holzes, p. 40. 



