American Wood-Preservers' Association 5 



which change them to simpler organic substances which can be absorbed 

 by the fungus as food for its own growth. 

 Fruiting Stage 



In order to propagate itself successfully every fungus must have 

 a fruiting or spore-bearing stage. Spores are very minute bodies which 

 in the case of molds are borne directly on the surface of superficial 

 mycelium, and in the case of the blue stain fungi also in minute, black, 

 flask-shaped fruit-bodies which appear as stiff bristles on the surface 

 of the wood. The wood-destroying fungi, however, have conspicuous 

 fruit-bodies whose shape, color and texture are quite characteristic for 

 the different fungi. The spores are borne on or within these definite 

 fruit-bodies. 



Spores are entirely comparable in function to seeds. They are 

 microscopic in size, extremely light, and appear in mass as a very fine 

 powder, very often white, but the color may vary widely for the 

 different fungi. Very often the spores from a single fruit body of 

 the wood-destroying fungi will run up into the billions, most of them 

 being capable under the right conditions of germinating to produce a 

 new plant. With such an abundance of spores blowing about in the 

 air and settling on new timber, it is seen that the chances for infection 

 are very great, providing the conditions for their germination are 

 favorable. The most important factor here concerned is moisture, 

 both in the wood and in the atmosphere. The most active period for 

 the casting of spores from the fruit bodies is during moist weather, 

 which in turn is most favorable for germination and subsequent in- 

 fection. 



Conditions Necessary for the Growth of Fungi 



The conditions necessary for the growth of fungi are: (1) The 

 presence of an adequate food supply; (2) sufficient moisture; (3) at 

 least a small amount of air; (4) a suitable temperature. 



Food. This is furnished by the wood tissues and the more easily 

 these tissues are attacked the more readily will the wood disintegrate. 

 The sapwood of all the species of the region under consideration is 

 non-resistant to fungus attack. The heartwood of the different woods, 

 however, varies widely in this respect. The white oaks are highly 

 resistant, as is also good red gum, while such species as beech, red 

 oaks, medium grade yellow pine, hard maple and birch offer less 

 resistance, and hackberry, elms, tupelo gum, cotton-woods, soft maple 

 and low grade pines are easily rotted. 



Moisture. A suitable amount of moisture is, without doubt, the 

 most important factor in decay. The different fungi, however, appear 

 to vary somewhat as to their water requirements. For infection and 

 incipient decay a comparatively high moisture content of the wood 

 and the surrounding air is highly favorable for all. After infection 

 has once taken place, however, and the fungus has become established 



