1922-23 DEPARTMENT OF LANDS AND FORESTS 203 



standing or fallen trees. They are in the form of white effused patches of variable 

 size, up to a foot or more in diameter, closely adherent to the trunk on which 

 they grow. Their surfaces are very finely porous. 



Feather rot, except in the later stages, is not marked by an excessive weaken- 

 ing of the fibres — apparently the cellulose is more resistant to the action of the 

 causal fungus than is the lignin. The actual loss in ordinary cutting operations 

 usually amounts to a short butt log; it is doubtful if even this is necessary. 

 Since feather rot may be present to the extent of fifty per cent, in some stands 

 the avoidance of such a loss would not be inconsiderable. There is also a large 

 loss traceable to this rot from windfalls. 



(3) Red heart rot of balsam. — Red heart rot (sapin rouge, or hemlock rot) 

 is by far the most important disease in balsam from the standpoint of utilization. 

 It is exceedingly prevalent. Fortunately the texture of the wood suffers less 

 impairment than in the case of most other rots, and as indicated in the quotation 

 introducing this section of the report, there are good grounds for anticipating 

 profitable utilization of wood affected with it. For an account of red heart rot 

 refer to the preceding section — "Sapin rouge, or Red Heart Rot of Balsam, etc." 



(4) Ahietinus or honeycomb sap rot of balsam. — This type of decay begins at 

 the surface of dead standing or fallen timber, or slash, and works inwards; all 

 parts of the tree are susceptible. It is one of the commonest of the diseases of 

 dead coniferous timber, and it extends with amazing rapidity under suitable 

 conditions of temperature and moisture. The affected wood turns a light straw 

 colour. Very small empty pockets soon appear in the older decayed parts so 

 that such wood is delicately honeycombed. It may continue inwards quite 

 regularly — dependent on the moisture content of the wood — until all parts of 

 the trunk and branches are involved. 



The cause is due to a fungus, Polyporus abietinus. The fructifications 

 develop very abundantly; hundreds of them may be seen scattered about in 

 flocks on the surface of diseased timber. They are bracket or scale shaped, thin, 

 tough, small (one-half inch to one and one-half inches in width), white or purplish 

 when young, ash-coloured to blackish with age, downy and somewhat zonate. 

 The lower surface is purplish, but this colour may fade to a cream or bay; it 

 is also porous. 



Abietinus rot is not marked by an excessive weakening of the fibres except 

 in the later stages. The outer honeycombed wood, however, is valueless; more- 

 over, it is largely worn away in handling before the mill is reached. In practice 

 it would seem that where this rot is the only defect a great deal of dead wood 

 could be profitably salvaged. 



(5) Brown sap rot of balsam. — Brown sap rot begins at the surface of the 

 trunks of dead standing and fallen balsam and works inwards. It is rather 

 closely restricted to the trunk but may attack the larger branches. In spite 

 of statements to the contrary it is doubtful that this is ever a disease of living 

 trees, at all events there is no experimental evidence in support of such a claim. 

 The affected wood darkens somewhat to a straw colour or dull light brown. 

 Very soon the decayed wood dries out and cracks in various directions. The 

 checks, large or small, that appear in this way fill up with delicate white sheets 

 of fungus tissue. But there is another distinctive feature — the wood has become 

 very friable, that is, it powders readily when rubbed between the thumb and 

 fingers; this is due to the removal of cellulose from the fibres. The decay, once 

 under way, extends in all directions, and very commonly in an irregular line 

 across the grain; it develops rapidly along cracks or checks. Eventually all 



