DISPOSAL OF INFECTED SLASH 37 



Lack of sufficient atmospheric moisture should also be considered 

 in connection with sporophore production. Work bearing on this sub- 

 ject has been done in connection with a study of the effect of thinning 

 on the sporophore production on trees left on the area.^^ Although 

 not conclusive, the results of the study indicate that the sporophore 

 production is checked by the thinning. Abbott ^ and von Schrenk ^'^ 

 refer to the relation of moisture to fungous development, but do not 

 state the effect upon sporophore production. Abbott, by experiments, 

 showed that wood infected with Trametes pini and kept moist con- 

 tinued to support live mycelium, but that lack of moisture soon caused 

 death. 



Light as a factor in sporophore production has been recognized for 

 some time, and considerable has been written concerning it. Goebel,® 

 Buller,^ Bayliss,- Long,^^ and Long and Harsch ^* have shown by 

 experiments that certain wood-rotting fungi cultured in darkness will 

 not produce fertile sporophores, but that the same fungi cultured in a 

 certain density of light produce them readily. Goebel, quoting from 

 Schroter, states that wood-rotting fungi growing in coal mines have 

 sporophore development visibly affected by the absence of light, and 

 Long and Harsch ^"^ have definitely demonstrated by cultures that light 

 is necessary to produce fertile fruiting bodies in a certain number of 

 fungi, and that three species of Polypores developed fertile sporophores 

 in absolute darkness. 



Light, in the majority of cases, it seems, is first needed to produce 

 the primordium of the fructification, and following this, gravity is 

 active in properly aligning the tubes of the hymenium or the gills so 

 that they are at right angles to the surface of the earth. This arrange- 

 ment makes it possible for the growing fungus to first secure a place 

 open to the light for the production of sporophores and proper dis- 

 semination of spores, and, second, guides the arrangement of the 

 hymenial surfaces in such a way as to secure the distribution of a 

 maximum number of the spores. 



Moisture is, no doubt, the predominating factor in determining the 

 continuous activity of forest tree fungi in infected slash, and is of 

 prime importance in the development of fruiting bodies. A study of 

 the moisture conditions and the attendant fungous activity on any par- 

 ticular area would greatly aid in determining the intensity of control 

 necessary to remove the danger of sporophore production on the 

 mfected slash left upon the area. 



