Forest Finance and Management 151 



subdivisions into which a forest is usually divided 

 are technically known as blocks and compartments. 

 They serve to mark the body of timber to be felled 

 each year, and are also convenient for various silvi- 

 cultural purposes. The number of compartments 

 ought to correspond, as nearly as possible, with the 

 number of years which the trees require to become 

 ripe for the axe, according to the principles already 

 explained. In a forest so arranged there will, con- 

 sequently, be trees of every age, from the seedling 

 to the ripe timber. It should be said that what 

 has just been stated applies especially to the system 

 of silviculture known as normal high forest. In 

 such systems as selection forest or coppice, consid- 

 erable modifications in applying these rules are re- 

 quired, but the principle remains the same. In all 

 cases the forester's aim is to have a sufificient quan- 

 tity of timber ready for marketing each year, and 

 to provide annually for the future supply of timber 

 by beginning a new reproductive cycle to supply the 

 place of what has been removed. The period elap- 

 sing from the time when the young seedlings begin 

 to sprout to the year when the mature trees are cut 

 is known as the rotation period. One speaks ac- 

 cordingly of a sixty-year rotation, a hundred-year 

 rotation and so forth. Generally speaking, the 

 production of ordinary lumber requires the longest 

 rotation. Where it is intended to raise special 

 kinds of lumber for manufacturing purposes, or 

 wood for pulp material, charcoal, or other industrial 

 uses, the rotation is often materially shortened. 



