18 PROTECTION OF PLANTS, 1921-22 



Blighted trees studied 358 



Cheeks (healthy trees) 275 



Of the checks two only have developed blight and under known conditions. 

 They blighted in 1919 following partial lifting of the thin soil cover and its 

 permanent displacement from the bed of coarse broken rock on which it lies 

 — the action of ice. These trees died in 1921. The blighted trees have been 

 divided into two classes; (1) Those with trunks 6 inches or less in diameter, 

 b.h. (II) Those with trunks more than 6 inches in diameter. 



From the results obtained it is reasonable to conclude (1) that young 

 stands are not likeh' to be seriously depleted by needle blight; (2) that injury 

 to heavily blighted mature stands may be so great as to be a deciding factor in 

 determining the time of harvesting; (3) that in regions subjected to sulphur 

 f tunes, it is possible to differentiate between blight and sulphur fume injury 

 if the examination be made at the right time; (4) that the malady is not contag- 

 ious and hence is solely of regional importance. 



(b) A heart rot of birch. {Fig. 3). 



A special case calhng for an investigation of the heartwood of birch, 

 normal in appearance but weakened from some unknown cause, was undertak- 

 en some months ago because of complaints of manufacturers using this wood 

 for spokes and other purposes demanding maximum strength. A preliminary 

 examination showed that this was due to a common fungus the relationship 

 of which had not heretofore been worked out, namely the true tinder fungus, 

 and that wood for the purposes mentioned should not be taken from certain 

 types of defective trees easily'' recognizable in the forest. 



The true tinder fungu? attacks standing or fallen beech, birch, poplar and occa- 

 sionally elm, causing a whitish decay. It is readily recognized by its fruiting- 

 bodies or sporophores, the grayish hoof-shaped punks or brackets so common 

 on the trunks of its hosts. Most frequently this fungus works from the crown 

 down, though not invariably so. The true tinder fungus abounds throughout 

 Ontario, and is also frequent in the adjoining states. Von Schrenk & Spaulding 

 (Von Schrenk, H. cz Perley Spaulding: Diseases of Deciduous Forest Trees, 



