DISPOSAL OF INFKCTED SLASH 35 



protected as much as possible from all manner of disease. This 

 protection from disease is aimed at reducing the chances of infection 

 through fungi, and the subsequent loss by decay or death, and favors 

 the development of a maximum of healthy trees for future cutting. 

 The prevention of sporophore formation is, therefore, the principal 

 method by which such protection can be secured. 



Factors concerned in the production of sporophores 



Various factors are concerned in the production of fruiting bodies 

 by forest tree fungi, some of which can not be taken up in detail 

 here. The most important can be grouped under two heads, the 

 internal factors or those depending upon the conditions within the 

 host, and the external factors or those depending upon conditions 

 present outside of the host. Of the internal factors, the principal ones 

 are as follows: (1) the stage of development of the mycelium in the 

 wood, (2) the available water supply, (3) the available supply of air, 

 (4) the available food supply, and (5) the resistance to sporophore 

 formation offered by the host. 



The important external factors are (1) temperature, (2) moisture, 

 (3) light, and (4) gravity. In the case of the Polypores a certain 

 ])eriod of development of the vegetative part of the plant is necessary 

 before sporophores are produced, and in the case of heart-rotting 

 fungi the stage of the rot is always sufficiently advanced to be plainly 

 recognized when fructification begins. This has been found true in 

 the studies made of Echinodontiiim tinctoriuin attacking western hem- 

 lock and grand fir,^^ ^^ and Trametes pint, Polyporus schzvcinitzii and 

 Fonies annosus attacking western white pine."''- In every case where 

 sporophores were present upon the host the rot within the tree, at 

 least in the infected area supporting sporophones, was always found 

 to be in a stage fairly well advanced and easily recognized. Hartig " 

 states that Trametes pini produces sporophores only when the fungus 

 has developed luxuriantly in the interior of the tree. Meinecke,^" in 

 discussing fungi which attack forest trees, says : "The fruiting bodies 

 are only formed after the fungus in the host tree has reached a certain 

 maturity at the cost of the tissues they live in." 



The development of the fungous mycelium within the host depends 

 upon the available water, food and air supply. The absence of suffi- 

 cient moisture even in the presence of a bountiful supply of food 

 material will cause the fungus to cease development and finally die. 

 This often happens to sections of infected trees left in dry. expo-ed 



