104 THE BOOK OF FORESTRY 
sttica. The spores of this fungus are carried by wind 
or upon the feet of birds and finding lodgment in a 
wound in the bark of a chestnut, start to grow. The 
fungus develops in the inner bark and kills the tree by 
girdling it, thus cutting off the sap supply. No remedy 
for this disease has yet been found and although it is 
not spreading as rapidly as when it was discovered in 
1905, it is still killing this valuable species in large 
numbers. The total loss at present has been estimated 
to be in excess of $25,000,000. 
Another fungus disease which was imported from 
Europe is the white pine blister rust which attacks 
small pine trees. This fungus has caused much 
trouble but is believed to be under control. It passes 
part of its existence upon the currant and gooseberry 
and if all the infected pines are torn out and burned 
and the same treatment is administered to the berry 
bushes within three or four hundred feet of the 
plantation the remainder is likely to be safe. 
The influence of the saprophytic fungi—those that 
attack only dead trees and timber—must really be con- 
sidered beneficial, for 1t is owing to their action that 
the trees and plants are so soon gotten out of the way 
and their substance is again returned to the earth to 
nourish the next generation of trees. 
As in a community of people, the loss in a forest 
is greatest in childhood, least during middle life, and 
then gradually increases with age. A forest is con- 
tinually fighting against these agencies and when we 
realize how the various tree species have survived 
throughout the countless centuries, the marvelous 
structure of a tree with its ability to resist and over- 
come these many agencies becomes apparent. We 
realize that the tree bears the same relation to the 
