CHAPTER XIII 



THE FUNGOID DISEASES OF FOREST TREES, AND 

 THEIR PREVENTION 



No small proportion of the disturbances which take place in 

 the growth of plants, and which vary from comparatively trifling 

 ailments up to serious injuries resulting in the death of trees, 

 is directly ascribable to the influence of parasitic, cryptogamous, 

 vegetable organisms called Fungi, which live on or in the 

 plants in question. 



Fungi are plants of lowly organization, consisting only of 

 cells and containing no chlorophyll. They consequently 

 cannot elaborate organic substance for themselves, and there- 

 fore only obtain their requirements in this respect by with- 

 drawing organic nutriment from other living or dead organ- 

 isms belonging either to the animal or the vegetable kingdom. 



Until the last few decades this pathological branch of phy- 

 tology received scant attention, so far as woodland growth was 

 concerned. Many of the fungal diseases of trees were unknown 

 and contemptuously disregarded ; whilst, with respect to some 

 others of a more prominent and widespread nature, cause and 

 effect were confused. The appearance of many fungi, e. g. 

 species of Polyporus causing red and white rot, was regarded 

 as the consequence of the rot in place of its cause ; and not 

 a few of the phenomena are still a sealed book to sylviculturists. 

 The Pasteur of this branch of Forest Science is Professor 

 Robert Hartig of Munich. 



