150 MODERN FOREST ECONOMY. 



advantages equal to what would be obtained by the divi- 

 sion of the forest into what I have] called equivalent 

 portions. 



With the attempt to do this commences the difficulties 

 of the undertaking. Equivalent partitions cannot be 

 obtained by divisions founded on equality of superficial 

 contents, neither can they be obtained by divisions 

 founded on the number of trees growing in each, or even 

 on the cubic contents of these. The soil, the exposure, 

 the kind of tree growing in different localities, the adap- 

 tation of the soil and of the exposure to the growth of the 

 kind of tree, or of trees, growing in each, the age or ages 

 of these trees, the rate of their annual increase at different 

 ages, the age or ages at which they respectively attain 

 their maximum growth, and at which they attain their 

 maximum of value, these, and twenty other points, must 

 be determined to furnish the data necessary to determine 

 equivalent partitions ; and such partitions are necessary 

 in order to ensure the full benefits of this method of forest 

 management being secured. 



If by a tentative process, based on superficial extent, as 

 it necessarily must be, modified in accordance with the 

 number of trees, and with the cubic contents of these, it 

 be sought to arrive at a division of a forest into equivalent 

 partitions, it will be found that constant modifications of 

 the division first made are seen to be necessary. By 

 proceeding to the work of partition with an extensive 

 knowledge of the natural history of the trees on the 

 ground, of the process of tree growth, and of much per- 

 taining to meteorology, and geognosy relating thereto, the 

 work will be found to be more easy ; but with all the 

 forest science which has as yet been secured, the work 

 must be to some extent tentative still ; and this is 

 accepted as a fact by the most advanced foresters of 

 the day. 



And while this has been accepted as a fact, it has also 

 been found that divide the forest or coppice wood as you 

 may, you do not secure a sustained production through 



