16. A note on the Terai Forests between the Gandafc 



and the Teesta* 



By I. H. Burkill. 



The Terai from the Gandak to the Teesta is a sill with a 

 very slight slope from north to south, most rainy in the east, 

 and decreasingly so towards the west, furrowed throughout 

 from back to front in a parallel manner by many rivers. 



Remote from the influence of man, it had been forest in 

 all its length. But man, the one animal with the power of 

 applying and in some measure of controlling fire, has by this 

 means partially overcome nature ; to date and from the south 

 he has driven back the trees before wide stretches of rice fields 

 in the areas which happened to be most easily burned clean, 

 and which, on account of the position of administrative cen- 

 tres were also most persistently attacked. 



It is fairly evident that some of the rivers, — those with 

 longer courses, — have played a great part in helping him to 

 make history; for these bring down sand and gravel, and 

 on the top of the plains' silt, build cones of deposit which 

 afford a percolation and a reduced fertility sufficient to modify 

 the nature of the surface of the soil and the density and cha- 

 racter of the vegetation which covers it, so that the surface of 

 the soil on the cones is made more easy to travel over at seasons 

 when rainy conditions prevail than that of the silt ; and the 

 vegetation is less tangled, one conspicuous element in it being 

 the sal tree (Shorea robusta, Gaertn.). Now it happens that a 

 little firing favours the sal tree by doing less injury to it than 

 to most of its competitors, so that by fire, applied in modera- 

 tion, it is caused to be more dominant than otherwise, produ- 

 cing a rather open forest. Such firing has certainly occurred ; 

 and the sal having been thereby encouraged, and growing only 

 on the sandy soils, the diversity naturally existing between the 

 vegetation on the river cones and in the lower hollows has 

 acquired yet more marked dissimilarities. Man has undoubt- 

 edly applied this firing through centuries ; he has always been 

 in a hurry to burn ; and where particularly he came and passed 

 into the forests, the more marked has his influence been, pro- 

 gressing from the first stage where the sal is encouraged, to the 

 second, where the firing being too frequent, it is destroyed ; and 

 the forest gives place to savannah, to grass, and then is ready 

 to come under the plough* 



The rivers did more than determine where the forest should 



