252 REPORT OF THE No. 3 



the wood is reduced to cottony shreds, with at the same time a fading of the 

 colour. In extreme cases the shreds may disappear to a greater or less extent, 

 leaving the butt hollow. One of the curious features of this decay is the frequent 

 occurrence of small black spots. 



Type III is quite similar, but there is a tendency for radial perforations 

 to form quite early in the decayed wood. There is also a delamination, (but 

 more tardy), and an eventual shredding. With this type we have found Poria 

 subacida associated as a causal agent. 



Type IV. — This is a heart rot confined exclusively to the main trunk and in 

 Quebec known as "hemlock rot" of balsam. In one case only so far have I 

 found it extending down to the butt. This heart rot is probably the outstanding 

 menace of the balsam stands of Eastern Canada at the present time. In some 

 stands recently cut over 65 per cent, of the timber has been rejected from this 

 cause, including what was left uncut because of its evident uselessness, and what 

 was culled from the skids. Regarding its distribution we have little information 

 other than what has been gathered in the course of our own investigations. It 

 is found in Northern Ontario, and in Western Quebec, but how extensively we 

 are as yet unprepared to state. It is extremely common in Middle and Eastern 

 Quebec. There is, as yet, no report from Gaspe, the Maritime Provinces or the 

 United States. 



The heart wood of this rot is rather firm and of a reddish brown colour. As 

 seen in a cross section of the trunk its outline is marked by radial extensions of 

 the decay, these rays being up to half an inch in width. Sometimes instead of 

 rays there is a more or less indefinite large-figured mottling. The decayed wood 

 is typically wet and heavy. Indeed, afTected logs float very badly; they are 

 known to the lumbermen as "sinkers." On tracing this decay downwards it is 

 found to pass into the "frost patches" or watery-looking spots commonly seen 

 in normal balsam at the time of felling. 



Infection has been found to take place through the lower dead branches or 

 branch stubs, and the decay appears to work very rapidly up and down in the 

 heart wood for long distances from these points. In addition, infection in tops 

 injured by the bud worm are very frequent and the decay starting there may 

 work down several feet. They are a frequent cause of the broken topped balsams 

 so common in such stands — the "chicots" of the French-Canadian lumberjack. 



Type V. — There is still a form that should be mentioned and that i s a root 

 rot due to the "shoe string" fungus or Armillaria mellea — one of the common 

 and abundant toadstools. This fungus attacks the roots of trees that have 

 just or recently died. It forms white sheets of fungus threads immediately 

 under the bark and these may work up some distance under the bark of the 

 stem. The sap wood is whitened and softened and occasionally the heart is 

 affected. The fresh decayed wood and sheets of fungus threads are phospores- 

 cent. Whether or not this fungus is the cause of the death of such trees is not 

 known. In Europe it is regarded as a highly destructive parasite of certain 

 kinds of conifers, but in America wide differences of opinion are held. 



The control of the butt and heart rots of the balsam is fundamentally based 

 on the age at which the host trees become susceptible to the attacks of the various 

 types, and the rate of deterioration subsequent to infection. Regarding the 

 "hemlock" rot of balsam in Quebec, Mr. W. E. Hiley, of the investigational 

 staff of the Forestry School of Oxford University, found that more than half 

 of the balsam trees over eighty years of age examined by him were affected, while 

 those under sixty-five years of age were almost invariably sound. If this finding 

 should prove to be general, a cutting cycle of sixty years would practically 



