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 conifers, 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. Figure 46 shows the dis- 
coloration of wood by a shelf fungus. The wood contains the 
fungus plant, which, when ready to produce 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 
durability of our woods, and 
Figure 46. ‘Shelf’? fungus on . ; 
the stem of a Pine (Hartig). thus avoid unnecessary waste. 
(a) Sound wood; (b) resinous wood; The soil and conditions 
(c) partly decayed wood or punk; ; . 
(d) layer of living spore tubes; under which wood is grown 
(ce) old spore tubes filled up; co : 43 eee 
re) fluted upper surface of the fruit- affect its durability. Conifer 
ing body of the fungus which gets ous woods with narrow annual 
its food through a great number 0 eile 
fine threads (the mycelium), its rings are most durable, espe- 
vegetative tissues penetrating the cially when grown on compar- 
wood and causing it to decay. i < é 
atively poor soils, in dense 
forests, and at high altitudes. On the contrary, the hard woods 
