29 



TIMBER 



of its edges, and there is a good deal of wane on the edges of 

 some hewn logs. Fig. 51 shows the section of a 17-inch 

 diameter tree ; the darker shading is the sapwood. As will 

 be seen by the full lines, there would not be much 

 difficulty in getting a 12-inch perfectly square log, and also 

 one practically free from sap, except just at the corners, out 

 of such a tree, but if the timber be cut along the inner 

 dotted line, which shows a 13-inch log, there will be some 

 wane on the corners and much more sap there, whilst if 

 cut along the outer dotted line, which shows a 14-inch log, 

 there will not only be a good deal of wane on the edges, but 



FIG. o3. 



the amount of sap will be considerably increased, and may 

 extend along the sides if the sap widens out in places. 



The converter naturally tries to get as large- sized mer- 

 chantable logs as possible out of the trees, hence the wany 

 edges on logs. 



A practical view should be taken of timber selection ; if 

 only a few logs or pieces of timber are required, there will 

 be no difficulty in getting them free from the defects de- 

 scribed ; but when a large quantity is required it is impossible 

 to avoid them, although timber containing them must be 

 carefully examined ; the best must be made of such timber as 

 can be obtained in the market. 



The pines and firs have generally few defects, except sap 



