1849J 



exercised hy Trees on. CUmaie. 



40T 



places so destructive to cultivation, that nothing can be made to 

 grow upon them. It is to this cause that I ascribe the sterility of 

 the heaths of Brittany. In vain have attempts been made to res= 

 tore them to their former fertility, they wiU never succeed, unless 

 we begin with restoring to them their shelter and their temperature 

 by replanting their forests.* 



This efifect of trees in mitigating the intensity of tropical heat 

 has also been alluded to by the present superintendent of forests 

 in our western presidency, who mentions that in the southern dis- 

 tricts of Guzerat the vicinity of the sea and the proximity of the 

 mountain tracts covered with jungle tend to render the climate 

 more mild and the temperature throughout the year, more equable, 

 than is the case in the other parts of the province. Farther inland 

 and in the immediate vicinity of the hills the heat is greater, and 

 in both situations the humid and loaded atmosphere in the S. W. 

 monsoon, is often painfuUy felt particularly at night. In the 

 whole of this district rain falls in greater quantities than to the 

 northward ; in the jungle districts to the east, the supply of rain 

 is said never to fail in the driest of seasons and it often falls there 

 when none is apparent in the more open districts. 



It is in such tracts as these that rivers rise, for from the num- 

 ber, height, and comparative proximity of the hiHs, to the south- 

 ward of the Taptee, we might a priori suppose that the supply of 

 water in that district would be abundant : and such is actually the 

 case as we find in a breadth of 50 miles, eight rivers, aU contain- 

 ing water throughout the year. Eeasoning from these facts we 

 may also predicate the sort of country in which these rivers have 

 their origin, viz., under-lying hilly tracts abounding in rich soil, 

 highly retentive of moisture and rendered stiU more so by luxuri- 

 ant jungle. t 



An instance of the quantity of rain increasing from trees being 

 planted is mentioned in a work, very recently published in St. 

 Helena, in which it is recorded that the quantity of rain which 

 falls on that island has greatly increased within the last fifty 

 years. The writer, after remarking that the past year (1847) 

 may be considered a good one for the farm and garden, notwith- 



* St. Pierre's Studies of Nature, vol. i., p\ 223, ed. 184.6. 



t Siirgeon Gibson in 'iV. Bomb. Med. ftud Phys, Soc. Journal, p, 37 and p, 4. 



