1921-22 DEPARTMENT OF LANDS AND FORESTS 251 



Our investigations on these trunk and root diseases have so far followed 

 along three lines: (a) the tabulation of the various types as to kind, host rela- 

 tionship and distribution; (b) the working out of a ready means of field and 

 laboratory diagnosis for each type; (c) consideration of particular cases in res- 

 sponse to special inquiries. To these, others should be added — such, for ex- 

 ample, as the rate of progress of an infestation, and the relation of butt diseases 

 to age, specific resistance and environmental factors. As a part of the scheme 

 of tabulation, it would be especially profitable to include information relative 

 to the age at which various species of trees lose their resistance to the inroads 

 of the different kinds of decay fungi. Observations show that, in general, this 

 feature will vary with location, and especially the characters of the physical 

 and the biotic environment — such factors, for example, as soil, crowding, etc., 

 and possibly climate. The factor of wounding or killing of roots is also im- 

 portant, for it is probable that none of the fungi concerned can gain entrance 

 into the host except through wounds or dead areas in the bark and cambium. 

 To what extent wounded and dead roots regularly occur in different localities 

 remains to be seen. But from an examination of the root systems of many 

 trees in the Temagami Forest Reserve, it is certain that in that region wounds 

 are very common on the centrally directed faces of the main roots, particularly 

 just below or near the trunk axis, and the inner roots are frequently dead. 



(a) Much progress has been made in the work of tabulation. The fund- 

 amental need of this undertaking is indicated by the fact that several types of 

 butt or heart rot have been found to be new. One of the most important of 

 the latter, and recorded here for the first time, is a root and butt rot of spruce, 

 hemlock, and white pine, with which a pored type of fungus, Polyporus Toment- 

 osus Fries, is constantly associated. On further search, it will probably be 

 found that the red and the jack pine should be included in this list, and possibly 

 balsam. The fruiting body of the fungus is yellowish, leathery in texture, 

 stalked, with a rounded cap 1-3 inches in diameter; it commonly grows on the 

 soil in the neighborhood of coniferous trees, but is attached by its stalk to the 

 covered roots of its host. The decay caused is of the piped or speckled type 

 — whitish spots at first in the rather darkened wood, later becoming small cav- 

 ities up to half an inch or more in length and a twelfth of an inch in diameter. 

 This decay quite closely resembles the common "pecky wood-rot" or "partridge 

 rot," caused by Trametes pint, but differs from the latter in that it is a butt rot. 

 While not infrequent throughout it is apparently much commoner in some 

 localities than in others. In the Otter district, for example, a high percentage 

 of the white pine was affected, and to such an extent that frequently the butt 

 log was of no value and was allowed to remain on the ground. I am indebted 

 to Mr. A. W. McCallum for striking specimens of this decay as a heart rot in 

 black spruce. 



(b) One of the chief drawbacks encountered in investigating butt rots is 

 the lack of information on the identity of the causal organisms. This applies 

 to the larger number of butt and heart rots of conifers in America. Balsam 

 rots may be cited as an extreme case, for though several types occur in living 

 balsam trees, no one as yet, so far as the literature shows, has definitely estab- 

 lished a connection with a specific fungus in any one case. To meet this need, 

 and as an outgrowth of the present work, investigations in this field were in- 

 dependently inaugurated in the provincial University two years ago, and are 

 now being vigorously carried forward with fruitful results. The methods em- 

 ployed are those so successfully used in cultural diagnostic studies of bacteria. 



