I I 8 THE LARCH. 



generally ascertained why, or what the real cause of 

 twisting is. 



It is not a satisfactory answer to the inquiry, why 

 does the larch wood twist, to say, because it is its 

 nature to do so. That is true ; but why it is its nature 

 to do so, and not the nature of the spruce or Scotch 

 pine, requires to be better explained. Trees that are 

 grown perfectly upright with an equal proportion of 

 branches on all sides, and, therefore, the layers equally 

 thick all round the pith, and the pith exactly in the 

 centre of the tree, do not, on being cut up, naturally 

 twist. The soil in which the tree grows has much 

 to do with the hardness of the wood, and, therefore, 

 also with twisting. All larch wood does not equally 

 twist. I have seen furniture of various kinds, agricul- 

 tural implements, flooring, and roofing, &c., made of 

 it, and nothing to complain of in regard to twisting. 

 Again, in sawing the wood much skill is required, and 

 it is by observing in which direction the natural curve 

 or bend lies that successful sawing can be done. The 

 trees, too, should be quite mature before being cut — 

 that is, the heart- wood should extend to as near the 

 surface of the trunk as possible. One principal cause 

 of twisting is the presence of -both sapwood and heart- 

 wood in the same deal or scantling. If a deal be 

 partly sapwood and partly heart- wood, the tendency is 

 to curve to the sapwood side, because the sapwood 

 contracts more, when exposed to sun and air, than 

 the heart- wood does ; therefore the stronger part forces 

 itself upon the weaker, which gives way. 



