54 JOURNAL OF FORESTRY 



destroying fungi and produce sporophores at an early date, are 

 small. If moisture and shade conditions remain favorable, the sound 

 slash may in time become infected and form a menace to the sur- 

 rounding trees. But in most cases this infection is from purely sapro- 

 phytic fungi, which do not ordinarily threaten living trees. Pomes pini- 

 cola is of this type, but is found acting occasionally as a heartwood 

 fungus and attacking the heartwood of living trees. 



In view of the preceding discussion the following suggestion is 

 miade to apply to timber sales in both groups where there is danger 

 that sporophores of harmful fungi forming a menace to the future 

 timber crop, will be produced upon inflected slash left on the sale 

 area after logging. To arrange the piling and burning of available 

 brush in such a manner as to ensure the effective burning up or 

 charring of a maximum of the infected slash left upon the area, and 

 to place the remaining infected slash in the best position for thorough 

 drying. 



SUMMARY. 



Certain factors are found to be concerned in the production of 

 sporophores of wood-destroying fungi. The most important ones are : 

 Available water and food supply, resistance of the host to sporophore 

 production, temperature, atmospheric moisture, light, and gravity. 



The sporophore of heart-rotting fungi is greatly dependent upon 

 the water and food supply. If the food supply be abundant and the 

 water supply inadequate, the fungus dies, and if the food supply be 

 exhausted a natural death results. Dry situations are unfavorable to 

 fungous development, and to sporophore production. 



The living host tissues in certain cases resist the production of 

 sporohores. This factor does not enter in considering down infected 

 slash, and sporophores may develop more readily on such material. 



Light is needed in the case of many fungi to stimulate the forma- 

 tion of fruiting bodies, and gravity causes the sporophores to assume 

 the most advantageous positions for spore dispersal. Sporophores 

 produced upon a standing tree and remaining alive will readjust 

 themselves to any new position and produce spores whenever the tree 

 is felled to the ground. 



It is found that all of the most destructive wood-rotting fungi 

 operating in the forests of the Northwest develop fruiting bodies on 

 their hosts after the tree is cut. 



The field data presented indicate that large numbers of sporophores 

 of various fungi are found developing upon infected slash left upon 



