DURABILITY; S8 



May [though if felling, as in the Himalayas, can be effected 

 in spite of the snow, the latter will prevent breakage of the 

 falling trees and the crushing of valuable underwood. — Tr.] 

 It may not be possible to fell during winter, and woodcutters 

 frequently prefer to fell large timber in the height of summer, 

 as the stems can then be readily barked and prepared for winter- 

 transport. July and August are, however, the very months 

 when the danger of infection by fungi is most formidable. 

 Whenever, therefore, in such places there is reason to fear that 

 felled timber cannot be dried readily, it is advisable to defer the 

 commencement of the fellings till September, and continue the 

 operations till winter commences. Even if the logs can be only 

 roughly barked, and the bast left on them, they will be the 

 better preserved. Whenever there is no strong objection to 

 winter-felling, it should certainly be adopted. 



Since the reserve-material contained in woody tissues is the 

 chief medium of decay in wood, it is evident that timber felled 

 immediately after a good seed-year will be more durable than 

 when it is felled before such an event, for the production of seed 

 employs very much reserve-material. 



Besides wood-sap and the substances it contains, conifers also 

 contain turpentine and resin in a more or less fluid state. 

 Foresters are often disposed to ascribe an antiseptic property to 

 resin, as it excludes water from wood, and the frequently great 

 durability of highly resinous wood confirms this opinion. The 

 importance of resin, in this respect, must, however, be taken 

 into consideration along with the various wood-destroying 

 agencies, and especially that of fungi. Whilst even moderately 

 resinous Scotch pinewood is as a rule more durable than spruce- 

 wood, the latter, even when highly resinous, may, under certain 

 circumstances, decay as rapidly as silver-fir wood, which is 

 scarcely resinous at all. The high durability of Scotch pine- 

 wood is due to its distinct heartwood, and to the fact that this 

 heartwood has become impregnated with resin, which, as the 

 timber dies, replaces water in the walls of the fibres. 



(c) That thorough soundness of the wood is needful for 

 durability is evident from the nature of the case. The only 

 question here is, how to decide as to the soundness of a piece of 



