Chapter XVI. 



Diseases of Timber and Shade Trees — Timber Rots. 



M 



Wound parasites and timber rots. Features of these sub- 

 jects have been treated of in former chapters and httle remains 

 to be said here. These fungi include chiefly members of the 

 palisade basidium-bearing groups, as pore and gill fungi. They 

 are capable of attacking woody tissues, feeding upon them, 

 and converting them into the crumbling, friable mass, known as 

 punk. Many of these forms are entirely saprophytic and occur 

 only on fallen logs, cut timbers or standing stumps and are sim- 

 ply timber rots. Others, however, are half saprophytes and 

 are capable of attacking the living tissues of the stem or root. 

 Such usually gain entrance through the bark, by means of 

 wounds in the latter and, after a more or less short saprophytic 

 life, penetrate outward to the living parts of the stem or roots 

 and there attack the growing zone and inner bark. The ulti- 

 mate result of this parasitic life is usually the death of the tree, 

 after which the fungus continues to live on in a truly sapro- 

 phytic manner. To the living forest trees, therefore, this 

 class of fungi is a constant menace, and to the fallen trunks 

 and broken trees almost a certain evil. The danger does not 

 even stop here, for many of these forms attack stored timbers, 

 and lumber, especially, if the latter is improperly kept. They 

 even invade the standing and foundation timbers of houses. 

 Some of the most serious problems in the construction of 

 wooden houses lie in the prevention of subsequent rotting. 

 The so-called dry rots are particularly harmful in this respect 

 and are frequently found in their fruiting stages in damp cellars. 

 Thorough seasoning is the only efficient remedy against such 

 diseases. Application of creosote to the ends of joists and other 

 timbers has also been recommended. Large timbers are often 

 bored through lengthwise and ventilating holes bored at both 

 ends at right angles to the long holes to allow of circulation of 



