64 Formation op Compaetmejjts. 



clayey, silicions, marly, rich or poor, . or by their looseness or com- 

 pactness, their depth, moisture, covering of dead leaves and vege- 

 table mould, &c. Climate and soil constitute the constant factors of 

 production, for naturally they cannot be modified except to a limited 

 extent. 



The chief elements of difference in the standing stock of a forest 

 are species, age and density. But the promise held out by the stock 

 and the state of ics growth also constitute points of difference. Again 

 although, speaking generally, the causes of difference are those 

 enunciated above, yet existing differences may also be directly due to 

 anterior circumstances special to the compartment in question. The 

 standing crop is thus an essentially variable factor of production, for 

 its condition is necessarily ever changing with its age, and that too 

 without any limit whatsoever, since one day at last the stock itself is 

 to be worked out and to disappear and be replaced by a new one. 



The essential reason for the division of a forest into compart- 

 ments, from each of the three points of view of climate, soil and 

 standing stock, is that the dissimilar portions of one and the same 

 forest require different cultural treatments or different rotations, and 

 it is precisely these very two points — cultural treatment and rota- 

 tion — that the Amdnagiste is required to determine. It would be 

 impossible for him to fix and prescribe clearly the treatment of, and 

 time for, exploiting each of these Dissimilar portions of the forest, 

 unless he studied them separately. By bearing this rule well in 

 mind, we are enabled to judge what amount of difference justifies 

 the separotion of one. piece of forest from another and their forma- 

 tion into separate compartments. Mere shades of difference do not 

 afford sufficient grounds for making a separate compartment of any 

 particular portion : we must have marked and notable differences. 

 But in that case the cause or the effects of the differences observed 

 are'at once apparent either in the configuration and condition of the 

 soil, iu the nature and relative proportions of the species, or in the 

 shape and size of the trees. The task of appreciating these differ- 

 ences is thus reduced to the question of ascertaining whether a cer- 

 tain given difference requires a different kind of treatment or a 

 different time fur felling the standing material. This question only 

 expeiience and a true s'jnse uf the Ameuagiste's art can resolve. 



