CONTEXTS 



Introduction t 9 



Environmental disease? 10 



Smoke and sulphur gases 10 



Unfavorable soil conditions 12 



Extreme cold 13 



Injuries caused by animals, wind, etc 14 



Diseases caused by miscellaneous parasitic and saprophytic organisms 14 



Diseases caused by insects 14 



Diseases caused by parasitic higher plants 14 



Diseases caused by miscellaneous fungi 18 



Mildews 18 



Tar-spot 19 



Rusts 19 



Sycamore leaf-blight 20 



Leaf-spots 20 



Leaf-blister fungi 21 



Nectria cin nabarina 21 



Chestnut bark disease 22 



Root-rots 22 



Slime-flux diseases 24 



Diseases caused by wound fungi - 25 



White heart-rot caused by Fomcs ign iarius 25 



Nature of disease caused by Fames igniarius 25 



Susceptibility of different hosts to the white heart-rot 26 



Distribution of Fames igniarius 27 



Description of the fungus 28 



Spread of the disease 2 l > 



Influence of environment on prevalence of white heart-rot 31 



Ultimate fate of diseased trees 33 



Effect of the fungus on the wood structure 34 



Preventive measures 35 



Red heart-rot caused by Polyporus sulphureus 37 



Piped-rot of oak and chestnut 39 



Soft rot of oaks caused by Polyporus obtusus 41 



Heart-rot caused by Fames nigricans 42 



Disease caused by Hydnum erinaceus 44 



Black locust disease caused by Fomes rimosus 45 



White heart-rot of ash caused by Fomes fraxinophilus 46 



Red heart-rot of birch caused by Fomes fulrus 47 



Soft heart-rot of catalpa caused by Polystictus versicolor 17 



Heart-rot of oaks caused by Fomes everhartii 48 



White-rot caused by Polyporus squamosus 4S 



Two sap-rots 49 



Decay caused by Fomes f omen tari us 50 



Decay caused by Polyporus betulinus 51 



5 



149 



