lOa EOTATION FOE COMMEBCIAt BXPLOITAEILlTYu 



trees the age at which the miaimum diameter required' is attained. 

 When there is choice in the matter, the trees selected for these 

 Gxperimental ring-countings should be such as have grown in cano- 

 pied high forest under the average conditions of fertility special to 

 theWorking-Circle concerned; those that present any exceptional 

 characters should be rejected.. The highest figure obtained from the 

 ring-countings should be fixed for the rotation, since it is better to 

 be above the minimum diameter required than to run the risk of 

 having to exploit the trees before they have acquired that diameter 

 But in practice, as a rale, the best trees found for these experimental 

 ring-countings do not quite satisfy all the points required of them ;. 

 for example, old crops, if they are present, may not be growing under 

 the average conditions of fertility, or may not have yet acquired the 

 desired dimensions ; or they may be entirely wanting in the Work- 

 ing Circle. If we were obliged to work with trees of larger girth 

 than the minimum required, it would be easy to determine, on a 

 section of the trunk, the age at which they reached this minimum. 

 But if such trees have grown in an isolated state, as they often do, 

 what are we to conclude as to the dimensions that would be acquired 

 at a given age ? And if large trees are absolutely wanting, a cir- 

 cumstance of not unfrequent occurence, what is there to do but to 

 fix the rotation by analogy ? 



However it be, it is obvious that individual judgment must 

 always, and to a considerable extent, come into play in the deter- 

 mination of the rotation to adopt. The greatest risk we run is, no 

 doubt, that of arriving at too low a figure for the rotation. The 

 effect of this would of course be that we would cut too fast the trees 

 that have already attained the exploitable girth, and thus in a short 

 time have no exploitable trees left to cut. 



SECTION IV. 

 Deteemination of the Age of Commeecial Exploitability. 



The object aimed at in subjecting a forest to the conditions of 

 Commercial Exploitability is to obtain the largest income from the 

 total sum in cash represented by the value of the forest. This sum 

 is treated exactly like moveable capital, and is expected to yield 

 the highest rate of interest possible. But the income derived from 

 wooded land is necessarily periodic ; any particular portion of it 



