Pakt III. ] Witt: Sylviculture of Hardwiclcia hinata. 
105 
It will be seen from these figures that the rate of growth varies very 
considerably in the different examples, from 9 rings per inch of radius to 
as many as 22 rings. These two examples may perhaps be taken as ex- 
treme limits, the average lying between 13 and 14. With these figures 
may be compared statistics of some trees of known age, planted on the 
Kistna Canal, Madras Presidency, taken from Gamble’s “ Manual of 
Indian Timbers,” which we have included in the table. Prom them we 
learn the rate of growth to be on the average 8 rings per inch of radius. 
There is, however, no information with regard to the soil and underlying 
rock, which vitiates to some extent the comparison. 
(iv) Comparison of rate of growth on trap and sandstone . — The 
data relating to the rate of growth on trap can be fairly well com- 
pared with that on sandstone, if we bear the following in mind : — The 
trees on the trap formation, having been planted in prepared soil and 
doubtless watered for the first few years, grew continuously, and were not 
exposed to the “ dying back ” process to which all naturally grown Anjan 
are subject, consequently the rate of growth in the earlier stages of the 
trees planted on the trap must necessarily have been very much more 
rapid than that of the naturally grown trees on the sandstone. 
Bearing the above in mind, let us continue the comparison. 
Our trees on the trap formation had an average radius of 4 C5 inches 
at an age of 37 years, corresponding as nearly as possible to the trees of 
54 years of age on the sandstone, taking this as the average age of the 
trees with a radius of 4 inches. If now we deduct 10 years, as being the 
time occupied by the naturally grown tree in establishing itself, we 
reduce the age of our 54-year-old tree to 44, and can then compare it 
directly with our trees planted on the trap formation, which have de- 
veloped continuously. It follows from the above, that our 37-year -old 
planted tree on trap corresponds to a 44-year-old planted tree on sand- 
stone ; that is to say, the rate of growth of planted Anjan on sandstone 
would average 11 rings per inch of radius as against 9 rings on trap, or in 
other words volume growth is more rapid on trap than on sandstone in 
the proportion of 11 to 9. 
One other point in this connection deserves mention. The examples 
of ring countings were obtained from an area of which the underlying 
rock was that very hard crystalline Vindhyan sandstone alread.y referred 
to under “ V . — Locality : (a) Depth of Soil.” This formation has a 
shallow surface soil, and other species do not thrive well on it. It is 
quite possible and even probable, that on the more porous and fissured 
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