200 REPORT OF THE No. 3 



thus making identification possible; fruits finally developed in August, 1923. 

 Meanwhile opportunity was afforded during the summer of 1923 to concentrate 

 on red heart rot in the field while engaged in assembling materials for utilization 

 tests of defective pulpwoods. Field observations revealed abundant instances 

 of the association of fungus fruit bodies, always of the same kind, with this 

 type of heart rot. This fungus {Stereum sangiiinolentum) fruits in great pro- 

 fusion on dead trees, J3rush, and fallen trunks. While the indications as seen 

 in the forest that Stereiim sanguinolentum is the cause of red heart rot of balsam 

 were convincing, additional evidence was essential. This was supplied by the 

 artificial cultures referred to above. In December last Miss Irene Mounce 

 thoroughly sterilized pieces of sound wood in test tubes plugged with cotton 

 wool and inoculated them with incipient red heart rot from living trees. Well 

 developed fruit bodies of Stereum sanguinolentum had formed in them before 

 the end of August, that is within eight months following inoculation. 



The fructifications of Stereum sanguinolentum are small, thin, leathery, 

 scale or bracket-like bodies one-half inch to one inch in width growing out in 

 flocks from dead standing timber, or the sides of fallen trunks and brush. When 

 growing on the under sides of fallen trunks or brush they are closely appressed, 

 brown or drabish, smooth, fungal patches of varying size. .The bracket-like 

 bodies are downy or silky on the upper surface, buff or pinkish-buff to dark ash- 

 coloured, and marked with darker, narrow, concentric bands. The lower surface 

 is smooth and drab to brownish in colour. One of the distinctive features of 

 either type of fructification is the fact that its edge or its smooth surface turns 

 blood-red where bruised. 



Red heart rot of balsam occurs in Ontario, Quebec, and Maine, and will 

 probably be found throughout the range of the balsam. It is especially prevalent 

 in balsam forests that have been ravished by the spruce budworm. Is it 

 susceptible to. control? 



The first step towards control of a parasite is a knowledge of its life history; 

 measures adopted can then be rationally based on known grounds. We now 

 know that red heart rot of balsam or "sapin rouge" is due to Stereum sanguino- 

 lentum and we know where this fungus fruits, that is we have located the source 

 of the germs or spores that are responsible for its spread. There is yet one 

 important point that is not fully determined, that is the age at which the balsam 

 becomes susceptible. Preliminary analyses indicate that this takes place in 

 general as the balsam approaches maturity. If this may be tentatively assumed 

 then two procedures are suggested, both of which would result in the prevention 

 of infection, one from the standpoint of the host, the other from that of the 

 parasite, and both are matters of forest management. In the one case the 

 adoption of a cutting cycle within the period of immunity would automatically 

 ensure freedom from the disease. In the other case burning of slash would 

 prevent the development of fructifications and so cut off the source of the spores. 

 The value of slash burning would probably be affected by the amount of dead 

 trunks and brush on the floor of the forest included in the burning process. 

 A combination of cycle cutting and slash burning would seem to assure complete 

 control. 



III. Types of Defective Balsam and Spruce Pulpvvood in Relation to 



THE Problem of Utilization. 



For several years past the Ontario Forestry Branch has been carrying on 

 studies of the diseases of pulpwoods, and especially of the trunk diseases of 

 balsam and spruce. These studies have embraced a determination of their 



