ROTATION. 109 



all the annual falls comprised within the working-circle. But 

 this loss is annually made good by the normal increment, so 

 that the normal capital remains theoretically the same from 

 year to year, reckoned at midsummer. The normal capital in 

 wood thus depends upon the length of the rotation and the 

 normal increment proportionate to the kind of tree, soil, 

 climate, aspect, elevation, &c. ; and there must he a regular 

 series of falls forming a simple arithmetical progression, 

 although such a felling series need not necessarily be distributed 

 in contiguous successive areas. Indeed, consecutive contig- 

 uous distribution is not desirable in practice, on account of 

 danger from wind, insects, fungus diseases, fire, &c. And, of 

 course, the area under each annual or periodic age-class must 

 depend upon the kind of crop, soil, aspect, &c. 



Rotation in forestry means merely the number of years 

 elapsing between the formation of any woodland crop and its 

 clearance or renewal when mature. Woodland soil does not 

 deteriorate under proper management, but gradually acquires 

 increased fertility or productivity, and especially in the case 

 of Beech and other close-canopied trees whose dead foliage 

 annually adds fresh humus to the soil. Sometimes a change 

 may have to be made from hardwoods to Conifers owing to soil- 

 deterioration, usually resulting from bad management; but 

 under good management a change back to hardwoods may in 

 course of time become possible, if then desired. The rotation 

 varies according to the kind of tree, method of treatment, soil, 

 aspect, elevation, climate, &c. Thus simple coppices may be 

 worked with a rotation of 10 to 20 years, or stored coppice with 

 20 to 30 years, or Larch, Pine, Spruce, and other Conifers with, 

 say, 50 or 60 years, Beech with 100 or 120, Oak with 140 or 

 150, &c., according to the given circumstances. And, of course, 

 for any given total woodland area, the longer the rotation is, 

 the smaller the annual fall will bej so that a private land- 

 owner will naturally prefer to work his woods with a low 



