THE ROTS OF WESTERlsr WHITE PINE. 3 



The sporophore (conk) of Tratnetes pini (ring-scale fungus) is 

 brown, woody, usually stratified, and varies in shape and thickness. 

 The usual form in the Northwest is a thin shell or scallop shaped 

 structure, but it may become hoof shaped or resupinate, depending 

 upon the position of the substratum or point of exit. Owing to the 

 tendency of the mycelium to spread more rapidly vertically than hori- 

 zontally in individual annual rings, a cross section of an infected 

 tree shows the decay in the form known as ring-rot. The wood when 

 first invaded by the mycelium of Trametes pini assumes a deeper 

 reddish brown than when normal. It first becomes visibly character- 

 istic with the appearance of pits in the wood lined with cellulose 

 fibers. This is the well-known " honeycomb " stage and is the most 

 characteristic stage of the rot. The decay, as indicated above, is not 

 uniformly distributed in the heartwood, but the rot column may vary 

 in location within the tree. This is also due to the fact that several 

 separate infections may occur in the same tree, the diseased areas 

 being separated by sound wood. As a butt rot, the general form of 

 the rot column is conical, tapering at the upper limits. In the upper 

 parts of the tree the rot column may be conical in both directions 

 from the area of greater decay or from the point of first infection. The 

 range of the vertical extent of the rot column in the tree may be from 

 a few feet to the entire length of the tree when acting as a trunk rot 

 and from 5 to 6 feet as a typical butt rot. External signs of the 

 decay are the fruiting bodies, swellings of the trunk in a region of 

 earlier infections, especially at branch whorls, due to the tendency of 

 the tree to heal the old " punk knots," resin flow at swelled whorls 

 or other points on the upper trunk, brownish punky material in old 

 branch knots from which old sporophores have fallen, hollowness or 

 punkiness indicated by soundings on the trunk, and the presence of 

 various injuries. 



Polyponos schweinitzii (velvet-top fungus) is usually not as con- 

 spicuous as the ring-scale fungus, owing to the fact that the sporo- 

 phore rarely appears on the trunk but usually develops on the 

 roots near by, and it may be partly obscured by the forest mold. 

 It often appears a considerable distance away from the base of the 

 tree. The fruiting body is in most cases stalked, the segments of 

 the top incurving and colored a deep, rich brown. The margins 

 when in a growing condition are of a lighter color. It sometimes 

 appears from old wounds on the trunk in the form of brackets with 

 or without a lateral stalk. The under side of the pileus is yellow- 

 ish green, which turns reddish if injured. The fungus usually pro- 

 duces a uniform heart-rot of the butt of the tree. It enters the roots 

 and decays the heartwood and may travel in this manner from root 

 to root to neighboring trees. The decay produced is a light reddish 



