344 
Indian Forest Records. 
[VoL. I. 
From which it appears that the number of first class trees available for 
exploitation is large, as compared with the number of second class trees. On 
the other hand, the third class trees are extremely well represented, as those 
of the lower classes are believed to be- 
Assuming that all the first class trees, 85 per cent, of the second class ones, 
and 65 per cent, of those of the third class, are able to survive till the end of 
the first period, an estimate which, if anything, errs on the side of safety, 
there should be on the ground just before the commencement of the second 
period : — 
First class trees 
Second class trees 
Third class trees 
15,836 
10,847 
22,904 
of which almost all the second and third class trees will, respectively. Lave 
attained to the sizes of the first and second classes. 
In view of these figures, and considering the present condition of the crop, 
and the results that may be expected from the proposed management, it is 
thought that it will be safe to remove all the first class trees, and one-fourth of 
those of the second class which are expected to survive to the end of the first 
period, during the first 30 years. This will give =618, 
say 620 trees a year. 
In making calculations of the capability it is, of course, necessary to con- 
sider the state of the younger age-classes, in order that, as far as can be fore- 
seen, the yield of the second period shall not be less than that of the first. 
Concerning the younger age-classes fairly reliable information is available, and 
assuming (a) that the duration of the second period wiU be 30 years and (6) 
that, during it, it will be possible to fell one-half of the existing 22,904 third 
class trees, which are expected to be on the ground, just before its commence- 
ment, there wiU be for the second period of 30 years — 
3^ trees a year, 
which means that there should be a sustained yield for 60 years, a yield which 
moreover may reasonably be expected to be able to be increased after that time 
has elapsed. 
In considering the above figures for the second period it must not be for- 
gotten that, probably, only 85 per cent, of the 22,904 third class trees will attain 
to the first class, so that reaUy more than half of the available number would be 
taken. 
In the next example to be considered a still larger proportion, 
Example IV. All Glass I one4hird of the Class II trees 
trees Jrd of the Class II are brought into the possibility. Thus in 
the case of the Siran Range forests* — 
The calculations given in paras. 24 and 25 of the Working Plan Repoit 
tend to show that the exploitable size for the chil may be safely fixed at 7' 6" 
in girth or 2 ' 6" in diameter, measured over the bark, corresponding 
to an age of 115 years, and that 32 years are required for a 2' 0" tree to 
become 2 ' 6 ". The number of trees over about 7' 0" girth which 
have passed maturity and have ceased to grow would suggest that possibly a 
lower felling size than 2 ' 6 " may be suitable, but at present there 
* Working Plan of the Siran Range forests, Hazara Division, North-Western 
Province, Punjab, by A. V. Monro, I.F.S., 1905. 
