398 



APPLIED SCIENCE 



straight and long and furnish excellent material for com- 

 mercial use. 



444. Felling Timber. Timber should not be cut until 

 it has reached its maturity. Before this time it contains 

 too much sap-wood. The time best adapted for cutting 

 timber is either midsummer or midwinter. In July or 

 August, the sound trees can be easily distinguished from the 

 unsound ones by the fact that the leaves of the former remain 



FIG. 189. Cutting Forest Trees. 



green while those of the latter become yellow. Trees are 

 felled by either chopping or sawing them near the base (Fig. 

 189). The small branches are then removed so that only 

 the stems (logs) of the trees remain. These logs are carried 

 on sleds to a saw mill (Fig. 190), usually situated near a 



