CHAPTER V. 



DURABILITY OF WOOD. 



Decay in wood is due to the breaking down of the tissues 

 by fungi. In some cases the fungus destroys the woody cells; 

 in others it uses up the starch found in the cells and merely 

 leaves a blue stain (bluing of lumber). Some kinds of fungi 

 attack only conifers, others only hardwoods; some are con- 

 fined to one species while others may affect several species, 

 but probably no one of them attacks all kinds of wood. 

 Figure 12 shows the discoloration of wood by a shelf fungus. 

 The wood contains the fungus plant which when ready to pro- 

 duce its spores, sends out a shelf-like body on the side of the 



wood. These shelves contain 

 the spores and may be found 

 on many old decayed trees or 

 stumps. Various odors are 

 produced in the wood by some 

 of these fungi: they may be 

 pleasant as those found some- 

 times in the oak or unpleas- 

 ant as those infesting some 

 of the poplars. By studying 

 both the favorable and the 

 unfavorable conditions for the 

 growth of the rot producing 

 fungi we may learn the best 

 methods of increasing the du- 

 Figure 12. "Shelf" fungus on the r ability of our woods and 



stem of a Pine (Hartig). a. Sound 



wood ; b. resinous wood ; c. partly thus avoid unnecessary waste. 



dec-ayed wood or punk; cl. layer of 



living spore tubes; c. old spore tubes Ihe SOll and conditions un- 

 filled up; fluted upper surface of j vuhioh wrrH i o-i-nwn af- 

 the fruiting body of the fungus which der wn lCh WOOd. 



gets its food through a great num- feet its durability. Conifer- 



ber of fine threads (the mycelium), 



its vegetative tissues penetrating the OUS WOOdS With narrow an- 



wood and causing it to decay. 



