256 FELLING AND CONVERSION OF TIMBER. 



Large billets always increase the solid contents of a pile of 

 stacked firewood, so that firewood also should be classified 

 according to dimensions. 



(c) Shape. 



Curved timber should be classed according to the degree of 

 curvature for a certain length, or in kneed-timber for the angle 

 at which the branch leaves the main piece. 



In classifying other timbers, the chief points to which 

 attention should be paid are : whether they are straight, 

 bent in one plane, quite crooked, or contain burrs ; also, 

 whether they are clean-grained, or merely have been trimmed 

 free from many branches and are knotty. 



In the case of firewood, also, straight billets of split or round 

 stem-wood should be piled separately from crooked and knotty 

 branch-wood. 



(d) Quality. 



Independently of its soundness, which is always presup- 

 posed in the case of timber, there is a great difference in 

 quality depending on its grain. Thus, we have coarse- 

 grained and fine-grained timber, timber with broad or narrow 

 annual zones, with straight, twisted, or wavy fibre. Some 

 stems are naturally smooth on the surface, others lumpy 

 owing to occluded knots. All these circumstances affect 

 the value of the pieces and should be considered in sorting 

 them. 



In the case of firewood any unsound and broken pieces- 

 should be piled apart from the better wood, and as the age of 

 the tree often influences the heating-power of the wood, 

 young or very old wood may be separated from middle-aged 

 wood. 



It cannot be repeated too often that only sound wood should 

 be classified as timber. Wood, in its present struggle against 

 iron and other substitutes for it, can win the day only 

 when it is sound and durable. This is especially the case 

 where the wood has to be transported long distances, and 

 is subject to indifferent treatment before it reaches the 

 consumer. 



