256 TIMBEK 



of the sapwood of trees being more readily destroyed by 

 fungi than the heartwood, as it is on these substances that 

 the fungi feed. 



The fungus threads penetrate the wood cells in all 

 directions and gradually destroy them. The fruiting 

 bodies of fungi are the familiar toadstools so commonly 

 seen on live and dead timber. Fungi are propagated chiefly 

 by the spores or fine filaments found on the lower surface 

 of the fruiting body, which, when ripe, are discharged in 

 clouds, float about in the air, settle on live or dead timber 

 and penetrate into cracks of the bark or wood, where they 

 germinate and gradually spread. 



When the fruiting body or toadstool appears on a tree it 

 is a sign that the timber is already badly diseased. The 

 growth of this fungus stops when the tree is cut down, but 

 then it is attacked by a number of other fungi, and the 

 work of destruction is very similar but goes on much more 

 rapidly on dead timber than on the living tree. 



In America experience has shown the curious fact that 

 on crests of hills or where winds have a long and free 

 sweep the percentage of diseased timber is uniformly 

 higher than in more sheltered areas, and that is due to the 

 larger number of broken branches forming cavities in which 

 the spores germinate. 



All trees and all timber are liable to attack by fungi, 

 although some are more liable than others ; for instance, 

 the wood of the cypress (Taxodium distichunt) and red 

 cedar (Juniperas virginiana) of America are remarkably free 

 from fungi and consequent decay, and so far as is known 

 the Locust (Rubinia pseudacia) is attacked by but one 

 fungus which destroys wood. 



So liable is timber to the attack of the numerous fungi 

 that Dr. Von Schrenk, of the United States Department 

 of Agriculture, says : " I will be willing to hazard the 



