Part VI.] Preparation of Turpentine, Rosin and Gum. 15 
(ii) Outturn. 
In order to form an estimate of annual outturn, we have to take 
into consideration the number of trees available for tapping, the yield 
per tree and the rotation on which tapping can be carried out. 
An approximate estimate has been given of the number of trees 
available in various localities, though no definite information is available 
as to how many trees fall into each girth-class, so that it will only be 
possible to base the calculation of outturn on the total number of trees 
available for tapping, multiplied by the average yield per tree from 
all sizes, and to divide that figure by the number of years of the fixed 
rotation. 
The average yield per tree of over 24* in girth, as ascertained in the 
North Khandesh experiments, in the case of trees not bruised before 
freshing, was 35*9 oz.=2*25 lbs. per annum. It is not possible to make 
any definite statement as to the best rotation of tapping : in Gwalior, 
they tap every year and give the tree no rest; from inspections in 
Nimar, it was thought that better results could be obtained by giving 
the trees two years’ rest, thus fixing the rotation at three years. Based 
on the above data, the following figures of annual yield have been 
arrived at:— 
Name of Division. 
Locality or name of 
Reserve. 
Number of 
Boswellia serrata 
trees available 
for tapping. 
Approximate 
annual yield 
available, in 
lbs. 
Remarks. 
Bombay Presidency— 
r 
1. Chopda Range . 
11,56,507 
8,67,380 
East Khandesh . . 
2. Yaval „ 
8,10,123 
6,07,596 
l 
3. Raver „ 
8,46,670 
6,35,002 
Total . 
21,09,978 
25,731 mds. 
West Khandesh . . «f 
1. Deomogra Reserve 
2,10,000 
1,57,500 
2. NaYapur „ . 
21,48,195 
16,11,146 
l 
3. Pimpalner „ . 
3,17,000 
2,37,750 
Total . 
20,06,396 
24,468 mds. 
North Khandesh 
Shirpur Range 
61,84,410 
46,38,307 
56,565 mds. 
Panch Mahals . 
Central Provinces— 
Number not 
known, pro¬ 
bably not large. 
•• 
Hoshangabad . 
Number not 
known. 
Potential out¬ 
turn large. 
Chhindwara 
Number not 
known. 
Fairly large. 
c 2 
[ 317 ] 
