Paet IV.] Caccia : Selection method of treatment in India. 363 
(ii) JFor 55 years — 
= 2'82 + 80 per cent, of 6'90 + 30 per cent, of 10'04 per acre. 
= 11‘35 per acre for 55 years. 
= 619 ■ do. 30 „ 
= 619 + 3,015. 
= 18,663 trees ; say, 18,600. 
(iii) For 120 years — 
= 2'82 + 80 per cent, of 6'90 + 60 per cent, of 10 04 F 36 per 
cent, of 18'7 + 12’6 per cent, of 30 per acre. 
= 24‘87 per acre for 120 years. 
= 6-22 do. 30 „ 
= 6-22 X 3,015. 
= 18,753 trees ; say, 18,700. 
As already stated, it is intended to restrict the fellings during the next 
30 years to a maximum of 12,000 1 Class sal trees in any one year. The balance 
to be reserved is 28'6 per cent, of the full number available. This provides an 
ample margin for possible overestimation of the existing stock, and of its rate 
of growth. 
The felling rotation is 30 years, for which period 30 annual coupes in each 
working circle are prescribed. Fifteen years hence (1917-18) the plan will be 
revised where necessary, in order to improve on the arrangement of coupes 
XVI to XXX. 
The followiiifr example, though not strictly appertaining to the 
Possibility calculated for general possibility method, may here be 
equal periods. quoted : — 
The Thonze Reserve,* like all other mixed forests in British Burma, will 
have to be worked on the system of “ Selection fellings.” As already stated, 
the rotation has been fixed at 150 years, which has been divided into five 
periods of 30 years each, the latter being the length of time it takes an 
average second class tree to attain first class dimensions. The present growing 
stock in the workable parts of the reserve is estimated as follows : — 
1st Class Teak trees 2 feet diameter and above . . 24,741 
2nd Class Teak trees 1^ to 2 feet diameter . . 37,867 
3rd Class Teak trees 1 to 1^ feet diameter . . 89,467 
4th Class dominant teak trees below 1 foot diameter . 192,827 
It is not likely that the whole of these will come to maturity, but as an 
approximation of the number of trees that will be available during the next 150 
years the following may be taken : — 
The whole of the first class trees .... 24,700 
Four-fifths of the second class trees .... 30,300 
Three-fifths of the third class trees .... .53,700 
Two-fifths of the fourth class trees .... 77,100 
Total . 185,800 
*■ Working Plan of the Thonze Reserve, Tharrawaddy Division, Pegu Circle, 
Burma, by J. W. Oliver, 1885. 
