Paet IV.] Caccia : Selection method of treatment in India. 393 
This method has now been in force in the vast majority of French 
selection forests for a period of a quarter of a century, and with 
excellent results. In the majority of cases, thanks to the degree of 
caution with which the possibility has been calculated (as above 
explained), the growing stock has improved, poorly stocked areas 
have become denser, and the mean girth of the stems has increased : 
though it is said that in some of the best forests, as a result of 
removing less than the true possibility, the growing stock has be- 
come over-mature, and over-dense.* 
Hi. — Fellings limited by Proportionate Volume. 
This method of determining selection fellings by volume of 
material is based on the assumption that as in a high forest worked 
by the regular method, a definite proportion of the crop on the 
ground is always felled, so, in a selection- worked forest by invari- 
ably limiting the fellings to a certain percentage of the volume of 
the crop, the fellings may be kept within the possibility. 
The method may be best explained by an example taken from 
D’Arcy’s Preparation of Forest W orking Plans in India, page 93 : — 
Applying the above theorem to a fairly homogeneous fir forest, containing a 
wooded area of 1,G00 acres in which the average annual production or capability 
of the soil has been ascertained to be 63 cubit feet of wood per acre a year, and 
assuming that the forest is worked by the regular method on a rotation of 
150 years, each acre would produce during the rotation 150x63 = 9,450 cubic 
feet, and the volume of wood at any time during this rotation would, on the 
whole area, be one-half of 1,600x9,450 or 7,560,000 cubic feet. Now, the area 
of the forest being 1,600 acres and the number of years in the rotation 150 years, 
the size of the annual coupes (the forest being worked by the regular method) 
would be 1,600 -h 150 = 10‘66 or lOf acres, and the volume of material felled each 
year would be lOfx 9,450 cubic feet = 100,800 cubic feet, or 1'33 per cent, of the 
total material in the whole forest. 
Similarly, were the rotation reduced to 100 years, the volume of wood on 
the ground would be (63 x 100 = 1,600) -^2 = 5,040,000 cubic feet; while the 
material removed at each felling, made on an area of 1,600-^100 = 16 acres, 
would still be 16x63x100 = 100,800 cubic feet. In this case, 2 per cent, of 
the material on the ground would be felled. 
Therefore in a high forest worked by the regular method, there is a fixed 
proportion, depending on the length of the rotation, between the volume of the 
material felled each year and the total volume of material or the wood capital 
of the forest. This proportion, following a general law, varies inversely as the 
length of the rotation; that is to say, it is higher as the rotation is shorter and 
vice versa. 
* An article by A. S. entitled “ Possibilite des Futaies Jardinees ” in No. 11, 
Vol. 47, (June 1908), of the Revue des Eaux et Foret, should be consulted. 
