Part IV.] Caccia : Selection method of treatment in India. 391 
the past by various causes, found throughout these forests ; also that in places 
the young oak poles are growing up so thickly as to be struggling with and 
interfering with each other. It will be therefore very desirable to arrange to 
replace such damaged stems by more healthy young growths, and to help tbs 
young oak trees where they are interfering with each other. At the &fime time 
then that the mature material may be removed by careful selection fellings 
improvement fellings of damaged stems combined with thinnings cf young 
poles should be carried out as may be found advisable according to the conditions 
obtaining in the compartment under treatment. These operations are of a com- 
plicated nature; and the officer marking the trees should possess the technical 
knowledge necessary to carry them out properly. Coupes will be formed, and 
the amount of material which may be taken from each one will be fixed. From 
the compartments placed in class B no trees except dead and dying ones must 
be felled. 
The oak being much the most important species, the exploitable age must 
be fixed wdth reference to it alone. Mr. Fernandez, in his w’orking plan for the 
Naini Tal reserved and protected forests, notes that though the mean annual 
production of oak trees goes on increasing up to a considerable age, yet after 
attaining a girth of 5 feet at an age of about 120 years, they spread out their 
crowns to such an extent as to cause great damage to all young trees in their 
immediate vicinity. He therefore fixes the size at which oaks can be cut with 
most advantage at 5 feet in girth, and calculates the exploitable age to be 120 
years. It is not, however, considered that we should be justified in accepting 
this conclusion. The theoretically true exploitable age is that at which the 
mean annual production is at its highest point. Mr. Fernandez’s experiments 
gave results as follows : — 
Girth. 
Age. 
Cubic contents. 
Mean annual pro- 
duction. 
Years. 
Cubic feet. 
5' 6’ 
120 
67' 
•55 
6' 6" 
160 
84' 
•53 
8' O'' 
205 
139' 
•67 
9' 9" 
250 
177' 
•70 
12' 5" 
330 
221' 
•66 
The mean annual production appears therefore to be at its highest point 
when the tree has attained a girth of about 10 feet at an age of about 250 years. 
Sound trees of such a size are, however, very rare; taking poor and rich soils 
together, the trees appear to be mature at a size of about 6 feet 6 inches, and 
to deteriorate and become unsound after passing this girth. Moreover, it is pro- 
bable that the old tree of 250 years of age, with its large spreading crown, will 
not be producing as much wood as the young growth which it prevents from 
occupying the ground underneath its cover would be. It is therefore considered 
that the most advantageous size to fell oak is 6 feet 6 inches, and the exploitable 
age is accordingly estimated to he 100 years. 
The general working scheme is to undertake combined selection and im- 
provement fellings throughout the compartments placed in class A, and by these 
fellings to remove the annual yield and no more. Ten years is proposed for the 
felling rotation. In this manner each coupe will have the benefit of nine 
