264 ELEMENTS OF SYLVICULTURE. 



flow of resin in the direction of the wound ; owing 

 to volatilisation, the tissues become impregnated 

 with solid resin, which increases the durability of 

 the sap-wood. Moreover, since the annual rings of 

 a tapped tree grow less thick, there is a large propor- 

 tion of autumn wood.* But no fair comparison can 

 be made, as it is rare to find a pine which has not 

 been tapped. Such are the pines which are left as 

 boundary marks ; they attain a great size, but are 

 usually felled only when they are in full decay. 



It is evident that in the portion of the stem along 

 which the quarres have been worked, the annual 

 rings of wood are neither continuous nor regular. 

 Hence it is useless for planking ; but it is split up 

 into vine props, which are much esteemed for their 

 durability : the solid resin, with which it is thoroughly 

 impregnated, prevents decay ; moreover, it often 

 yields small staves for casks which are to hold the 

 solid resin products. The upper portion of the bole, 

 however, contains timber with continuous rings of 

 wood. At Cape Breton I saw planks seven feet long 

 by seven inches broad and an inch and a quarter 

 thick, made from this portion of the tree. A hundred 

 such planks would contain over forty cubic feet of 

 wood. The hundred are sold for JG2 16s. 



This Pine is also used for making railway sleepers. 

 When impregnated, they are worth Is. Sd. each, 

 delivered at the railway stations. To demonstrate 

 their importance, it is enough to observe that the 

 railways in the south of France and in the north of 

 Spain are constructed of this pine. 



* According to the law of growth in coniferous species ; see note 

 on p. 86. 



