CHAPTER XIII. 

 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 con- 

 ifers, others only hard 

 woods; some are confined 

 to one species while others 

 may affect several species, 

 but probably no one of 

 them attacks all kinds of 

 wood Fig. 63 shows the 

 discoloration of wood by a 

 The wood 



, r~-j con tains the fungus plant, 



punk; d, layer of living spore wnich when ready to pro . 



tubes; e, old spore tubes filled . - , 



up; /, fluted upper surface of duce its spores, sends out 



the fruiting body of the fungus a shelf-like bodv on the 



which gets its food through a . . , , ". _., 



great number of fine threads Side of the wood. These 



(the mycelium), its vegetative shelves contain the spores 



tissues penetrating the wood , . . . 



and causing it to decay. and may be found on many 



old decayed trees or stumps. 



Various odors are produced in the wood by some of 



230 



FIG. 70. "Shelf" tungus on the 



stem of a pine (Hartig) a, shelf f unffus 

 Sound wood; b, resinous wood; 

 c, partly decaved wood or 



