Part II] Hole: Regeneration of Sal (Shorea robust a) Forests *21 
(8) The plants in the western half of Plot V are believed to have 
developed under the most favourable conditions which are 
possible under shade. Working the soil and removing the 
annual crop of dead leaves in these forests has been found to 
improve materially seedling development, and in this case 
the soil was dug and the humus removed twice before the 
seed was sown in 1913. Again, during the 5J years of the 
experiment, the annual crop of dead leaves was removed from 
the plot every year, with the only exception of 1916 when 
the leaves were left to decay on the surface. The seed, also, 
was sown in 1913 which was one of the most favourable 
seasons possible, with frequent showers throughout June 
and July to facilitate germination and a dry September to 
improve the soil-aeration. There is no doubt that these 
conditions are more favourable than we are usually likely 
to secure on a large scale in our forests. That this is the case 
is also indicated by the fact that, in this small area, two of 
the seedlings surviving in January 1919 had never died 
back, and showed a height-growth of 9 inches and 12*25 
inches (this was much the best plant in the whole area) 
respectively, which is quite exceptional for these forests. 
Notwithstanding these favourable conditions, however, the 
results are obviously extremely poor, with the number of 
surviving seedlings steadily diminishing from year to year, 
with only 7 per cent, survivors after 5^ years and with an 
average height-growth of only 10J inches after 5J years. It 
will be noticed that the height-growth at present is almost 
stationary with an average of 10*8 inches in July 1916, and 
10*6 inches in January 1919, in the unburnt western portion 
of Plot V. This is due partly to the death of individual 
plants, and probably in part to the dying back of the shoot 
in others. 
(9) In (6) above, it has been shown that the average annual height 
growth of seedlings in this locality is fairly constant up to a 
height of about 5 feet. (In para. 6 above, it has been shown 
that, in the Dehra Dun Garden, this remains fairly constant 
up to a height of 22 feet.) It is, therefore, possible to estimate 
the period likely to be required for the establishment of 
* seedlings of any particular size under shade from the measure 
ments of the 5-J year old plants in Plot Y. The two plants 
in Plot V which had not died back showed a height-growth 
of 9 inches and 12*25 inches, respectively, giving an average 
[ 183 ] 
