204 REPORT OF THE No. 3 



of the wood is involved if favourable moisture conditions prevail, so that in 

 the end it is converted into an easily powdered brown mass. 



Brown sap rot is caused by a fungus, Fomes pinicola, the fructifications 

 of which are of rather frequent occurrence, but as a rule only one or two or 

 three on the same trunk or stump. They are large, thick, hoof-shaped, perennial 

 brackets, up to six inches in width and two or more inches in thickness. Their 

 upper surface is gray to blackish, with or without a red rim; it is also concentric- 

 ally ridged and furrowed. The under surface is very finely and compactly 

 porous, and whitish, bufif, or cream-coloured. The substance of the interior of 

 a fructification is especially distinctive as it is chamois or pale buff in colour 

 and very felty tough. 



Timber much affected with brown sap rot is of no value. In less severe 

 cases difficulty might be experienced in grading closely because of the unevenness 

 with which the decay extends. 



(6) Yellow sap rot of balsam. — This is a rot of the sapwood of dead standing 

 or fallen timber. It is caused by the same fungus agent as that which causes 

 red heart rot or sapin rouge, namely,- Stereum sanguinolentum. The general 

 features of the decay are the same as were described under the heading, "Red 

 heart rot of balsam," except that the decay is more uniform and freer from 

 mottling. It resembles the abietinus rot except that there is no honeycombing. 

 As with the heart rot, the affected sap wood remains firm and hard for a long 

 time so that it is doubtful if its pulping value is materially lessened, at all events 

 in the earlier stages. A great many dead trees and chicots or stubs have been 

 found in the course of our field work, suffering from no other defect, and from 

 which much timber could apparently be salvaged. 



B. Types of defective spruce. (1) Brown butt rot of spruce. — This type of 

 decay is like the brown butt rot of balsam. The cause has not yet been defin- 

 itely determined, in other respects a separate account here is not necessary. 



(2) Abietinus or honeycomb sap rot of spruce. — This decay of spruce is like 

 the abietinus rot of balsam, and the cause is the same. 



(3) Brown sap rot of spruce. — This decay of spruce is like the brown sap 

 rot of balsam, and the cause is the same. 



(4) Pecky heart rot of spruce. — This rot is also known as "ring shake." It 

 is a heart rot and quite commonly extends through all of the trunk. Occasion- 

 ally the stump and main roots may be affected, though not as a rule. A similar 

 butt rot (apparently quite identical for all practical considerations) is due to 

 an entirely different fungus. Pecky heart rot is primarily a disease of living 

 timber, but continues to spread in dead or fallen timber; it is very common in 

 spruce and pine; it is infrequent in balsam. 



The affected heart wood in the course of decay darkens to some extent to 

 a brownish or reddish colour. Very soon small white "pockets" begin to show 

 at many points thickly scattered throughout the discoloured wood. The white 

 pockets consist very largely of whitened, more or less separated fibres; this 

 result is brought about by the localized removal of the lignin, and of the cement 

 that holds the fibres together, so that in these spots the firm wood is changed 

 to pure white, loose, cellulose fibres. With the progress of the decay the white 

 patches enlarge until the affected wood is entirely filled with them. Eventually 

 the white fibres may disappear, leaving the wood quite coarsely honeycombed, 

 that is, full of small empty cavities separated from one another by thin parti- 

 tions, but that comes about very tardily. This rot is one of the most easily 

 recognized in cut timber because of its characteristic white "pockets" and is 

 one of the best known because of its frequency in cheap grades of coniferous 



