392 
Indian Forest Records. 
[VoL. 1. 
years’ rest before fellings again pass through it, and the fellings which will 
remove ten times the annual production of the coupe will not be too heavy. 
The total available stock now on the ground amounts to 601,000 maunds 
(100 lbs.) of fuel; the exploitable age has been estimated to be 160 years, and 
the mean age of the crop may therefore be considered to be 80 years. The 
annual production is then 7,500 maunds, and this is the possibility.* * In this 
estimate no account has been taken of stems under 18 inches in girth. There 
are a great number of such; but they are in reality part of the future crop, not 
the present one, and by ignoring them we form a most necessary reserve, which 
will go to enrich the forests and render them more complete and valuable. 
a. — The French Method. 
This method was first introduced into France in 1883, and it has 
since then been applied to a large number of hill forests, treated 
under the selection system. The method is applied as follows : — 
Firstly . — The diameter of the exploitable tree having been fixed, 
the trees standing in the forest are divided into 3 diameter classes, 
namely — 
Class I = over % of diameter of exploitable tree. 
Class II to f ditto. 
Class III=under ^ ditto. 
Secondly . — The proportion between the volume of material in 
Class I and Class II is ascertained. In a normally stocked forest 
this proportion should be as 5 : 3.t If this proportion does not 
exist it may be found possible to make suitable transfers from one 
class to another. 
'Thirdly . — The possibility is fixed by dividing the volume of 
material finally remaining in Class I (as amended) by ^ of the num- 
ber of years in the exploitable age. 
As a precautionary measure, the increment which the Class I 
trees will lay on during the period for which the possibility is cal- 
culated (namely, ^ of rotation) is omitted. Again, any fellings 
which it may be found necessary to make in the woods of Class II 
will count against the possibility, although no allowance for this 
has bean made in calculating the annual yield. 
601. 100 
* *•«•> 160 =7,500 tnaunda. 
Volume of wood in ClaBs I_ 
t i.e., of wood in ClasB n~| rv 
f rv + rv 
‘3 
i rv 
ploitable'age ; ▼=> mean annual increment per acre). 
X a 
“3 
1 + J 
5 (where a = area ; r~ ex- 
