256 
TIMBEE 
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 proi)agated 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 (Taxodmm disticJiuni) and red 
cedar {Juniper as virginiana) of America are remarkably free 
from fungi and consequent decay, and so far as is known 
the Locust {Rohinia 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 
