ACACIA 433 



moisture, (3) loose soil, and (4) absence of grass and weeds. Apart from these 

 factors germination is greatly stimulated if the seeds have been swallowed by- 

 animals and ejected by them. 



The effect of complete light may be seen in any babul tract. Successful 

 reproduction never appears under or even close around seed-bearers, but 

 always in open gaps fully exposed to light. The effect of abundant moisture 

 is seen in riverain tracts, where successful reproduction depends largely on 

 the extent of the annual floods, failure usually following abnormally dry 

 seasons. In tank beds in Madras it is noticeable that natviral reproduction is 

 most plentiful where the ground is annually inundated and scanty on the higher 

 ground. Seedlings are, however, sometimes killed out by excessive flooding, 

 not only in riverain tracts but also in depressions on flat ground. In riverain 

 tracts it is probable that considerable loss is caused by seeds and seedlings 

 becoming buried in thick deposits of silt. 



The effect of loose soil is most marked, since it has a direct influence on 

 the development of the taproot, and causes soil-aeration and the retention of 

 soil moisture. For this reason vigorous natural reproduction frequently springs 

 up on ploughed land and on new embankments, while on hard un worked 

 ground reproduction is usually scanty or absent. The presence of rank grass 

 and weeds is one of the factors most adverse to the establishment of natural 

 reproduction, babul seedlings being particularly sensitive to suppression. In 

 this respect grazing is advantageous in keeping down a rank growth of grass. 

 One of the worst weeds in babul tracts of the Peninsula is Cassia Tora, which 

 sometimes forms a dense soil-covering and effectually prevents reproduction. 



The importance of animal agency in promoting the germination of the 

 seeds has already been alluded to. Apart from this grazing animals perform 

 a most useful function in spreading the seed over ground on which they are 

 herded, and which is usually kept free of grass and weeds. Both in inundated 

 riverain tracts and on other lands subject to grazing the seed is brought on to 

 the ground very largely by animals, and the existence of many babul groves 

 may be traced directly to their agency. The young seedhngs as a rule require 

 protection from cattle only for about six months or less, but protection from 

 goats is necessary until the plants are well out of their reach. 



A consideration of the factors just enumerated does not, however, always 

 solve the question of natural reproduction, the presence or absence of which 

 in patches of varying extent for no apparent reason is not always easy to 

 account for. Thus good patches of even-aged reproduction frequently occur 

 in places where attempts to regenerate artiflcially by scattering seed on the 

 ground have resulted in failure, and this would indicate that there may be 

 special reasons for such natural reproduction establishing itself only under 

 certain favourable conditions, whether seasonal or otherwise. 



Artificial reproduction. The choice between direct sowing and 

 transplanting from the nursery is easily decided, for owing to the sensitive- 

 ness of the taproot transplanting on a large scale is out of the question for 

 forest purposes. Numerous transplanting experiments at Dehra Dun, in which 

 roots and stem were in some cases pruned and in others left intact, resulted 

 in almost complete failure. Only when very small plants of the first season 

 were transplanted early in the rains with great care, and watered in dry weather, 



2307.2 H 



