HOLE : SOME INDIAN GRASSES AND THEIR CECOLOGY. 125 



Once these species or some of them have been established, a shrub which it is believed 

 would be of great value if introduced as an underwood is Adhatoda Vasica. This plant is 

 xerophilous although a strong shade-bearer and on account of its power of increasing the 

 humus content of the soil it would probably help to establish soil moisture conditions suit- 

 able for sal and thus facilitate the ultimate introduction of the latter, where this is consi- 

 dered advisable. 



104. As regards those grasslands where frost 

 damage is not severe it should be remembered that where — 



Saccharum Munja is dominant the locality is usually suitable for Dry Miscellaneous 



Forest, 

 Saccharum Narenga is dominant the locality is usually suitable for Sal Forest, 

 Erianthus Ravenna? is dominant the locality is usually suitable for Moist Miscella- 

 neous Forest, 



and that careful protection from fire and grazing will, as a rule, result in naturally replac- 

 ing these types of grassland by forest of the parallel type. Acacia Catechu has been seen 

 establishing itself naturally in thickets of Saccharum Munja, Mallotus and Cedrela have 

 similarly been seen ousting Erianthus and it is believed that Sal can do the same with 

 Saccharum Narenga, but artificial sowings would naturally hasten this result. 



105. The study of the cecology of Sal has only 

 recently been commenced at Dehra Dun and owing to the want of necessary staff and appli- 

 ances it has only been possible to carry out a few preliminary and comparatively rough 

 experiments for the purpose of determining the factors favourable for the establishment of 

 Sal reproduction. A full account of these experiments is beyond the scope of the present 

 paper and this will be published separately, but it is interesting to note that so far as they 

 go these experiments show — 



{a) That in this locality a number of sal seedlings die back in September — Decem- 

 ber owing to the rapid drying of the soil after the close of the rains. This 

 injurious action is most marked on sand, less so on stiff loam and least in 

 garden soil which contained a considerable admixture of humus. There had 

 been no frost when this dying back was noticed and where the seedlings on 

 these three classes of soil were regularly watered they did not die back. 



(b) That Sal is markedly sensitive to the intensity of light. The leaves are coloured 

 red when young and even when mature they possess considerable power of 

 movement frequently turning their edges to intense light and the upper sur- 

 face of the lamina to diffuse illumination. 



That, in this locality, seedlings grown in stiffish loam, similar to that on 

 which most of the local sal forests are found, develop more successfully [as 

 judged independently by (i) the percentage of stems which die back and by 

 (ii) the air-dried weight of the best stems which survive] when provided with 



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