272 Journal of the Asiatic Soc. of Bengal. [N.S. , XII, 1916.] 



Conclusions. 



1. The natural vegetation of the Terai between the Gan- 

 dak and the Teesta is forest. 



2. The sand-carrying rivers which traverse it, by altering 

 the nature of the surface soil promote the growth of the sal 

 tree, Skorea robusta. 



3. This effect is local, and determines the distribution of 

 sal forest and diverse forest. 



4. Man finds it easier to burn in the sal forest than in 

 the diverse forest: and by moderate burning he encourages 

 the growth of the sal, thus intensifying the differences be- 

 tween the two kinds of forest. 



5. But as the pressure of man becomes heavier, the 

 whole forest is destroyed by the firing; and, the pressure vary- 

 ing according to population, the south limit of the Terai forest 

 exhibits bays where this attack has progressed most. Both 

 from the greater ease of burning the areas covered by sal, and 

 from the greater population which the neighbourhood of the 

 rivers is able to support in comparative health, these bays are 

 on the courses of the sand-carrying rivers. 



6. The Gandak and the Teesta, the largest rivers of this 

 part of the Terai except the perhaps- very-modern Kosi, have 

 had from time immemorial trade routes connected with them, 

 as a consequence of the suitability of the neighbourhood of the 

 banks of a big river for travel in a land annually subject to 

 flooding: and by the frequent coming and going, along these 

 trade-routes the Terai forests have been particularly open to 

 the attack of man. 



7. This attack on the Terai forests, in the time before 



the Mohammedan irruption into Bengal, was effective enough 



for towns to spring up in the Terai belt, near the trade routes, 



towns which by their size would need large clearings about 

 them. 



8. But between the trade routes both north and south of 



the Terai forest, want of a through traffic kept the land from 



developing, and the inhabitants of Northern Purneah and of 



the Himalaya north of Purneah, remained economically back- 

 ward. 



9. In the eighteenth century, Northern Purneah emerged 

 into a transition phase between forest and cultivation, such as 

 we can see in the Eastern Duars at the present time. 



10. In the process nearly all the formerly existing tree 

 growth was burned off, and although we find now that the 

 landscape is full of trees, they are bamboos and mango-trees 

 whose planting is certainly very recent. 



