26 
Indian Forest Records. 
[VOL. III. 
large dimensions. The rate of growth in the Mohnyin reserve, however, 
is not so fast, the average age of a tree 7 feet in girth being 166 years 
(without allowances for the establishment of the seedling). It would 
appear from this fact that teak does not necessarily always show rapid 
growth on alluvial flat land. 
With regard to small alluvial flats along the banks of streams in hilly 
country, the working-plans do not as a rule discriminate sufficiently 
between these localities and the surrounding hilly tracts to warrant any 
wide generalization, but such data as are available point as a rule to 
the fact that the rate of growth on these alluvial flats is faster than else¬ 
where. To quote a few examples : (1) In the Yeni reserve countings of 
rings were made on 343 stumps, the average annual girth increment being 
0*524 inches : of these 26 stumps were on land described as level, without 
bamboos, and the average annual girth increment of these is 0*737 inches : 
(2) In the Minbyin reserve the mean annual girth increment of all stumps 
up to 7 feet in girth is 0*485 inches : of these 8 stumps were on flat alluvial 
land without bamboos, and these show a mean annual girth increment 
of 1*046 inches, that is, the rate of growth on the alluvial flats is more 
than twice as fast as it is elsewhere : (3) In the Ngalaik reserve the 
average age of 72 stumps at 7 feet girth is 140 years : of these 4 stumps 
were on flat alluvium, and these average 85 years at 7 feet girth. So far, 
then, the evidence available from existing working-plans generally tends 
to support the belief that if other conditions are equal, the rate of growth 
on alluvial flats is usually faster than it is elsewhere. 
(3) Influence of aspect on the rate of growth. 
During ring-countings and borings with Pressler’s borer, the aspect 
of the slope on which these were made has been recorded in some working- 
plans. It was hoped that the compilation of the results might give some 
definite information regarding the effect of aspect on the rate of growth 
of teak. The information afforded, however, can hardly be regarded as 
entirely conclusive. 
In compiling the figures given below only the results of ring-countings 
were taken, borings with Pressler’s borer being entirely discarded as not 
giving sufficiently reliable results. This being so, the workmg-plans 
containing the required information are those of the Kale working circle 
in the Myittha Division (area 223 square miles) and the Yeni, Minbyin, 
Yanaungmyin Kaing and Palwe, Taungnyo, Pozaungdaung and Ngalaik 
reserves of the Pyinmana Division (total area 791 square miles). All the 
Pyinmana reserves, which are situated on the eastern slopes of the Pegu 
[ 26 ] 
