INCREASE OF RAINFALL WITH GROWTH OF FORESTS. 117 



been covered with a dense growth of young trees. Over this region the 

 rainfall has been as follows, at the stations named: 



Badniir 



Chindwara. 



Seoni 



Mandla 



Burha 



Bilaspur . . . 

 Kajpur 



Annual average . 



1875 and before. 



Years. 



1867- 

 1865- 



1865- 

 1867- 

 1807- 

 18^5- 

 186G- 



1875 

 1870 

 1875 

 1875 

 1875 

 1875 

 1875 



Mean 

 annual. 



Inches. 

 39.83 

 41.43 

 52.07 

 53.58 

 64.51 

 41.85 

 51.59 



49.27 



1876 



to 



1885. 



Inches. 

 47.83 

 48.48 

 54.76 

 56. 32 

 71.65 

 54. 81 

 54.41 



55.47 



Per cent 



of 

 increase 



20 



17 



5 



5 



11 



21 



5 



13 



From the 37-year series of observations at Nagpur, and the 40-year 

 series at Jubbnlpore, on the north side of the Satpuras, it appears that 

 the probable error of a 10-year series of observations is 5 per cent. 

 Farther, it appears from the combination of rainfall observations in 

 India that in 187G-1885 the rainfall was O.G() inch (17 mm.) greater 

 than in 1866-1875. 



If one half of the above difference be attributed to error and to a gen- 

 eral increase of rainfall, there yet remains an appreciable addition which 

 might be attributed to the growing forest. At least it may be taken 

 as an indication which, combined with the results of observations above 

 trees, makes a good presumption that a forest does actually increase the 

 rainfall by an appreciable percentage. It should be noted that the for- 

 est fires practically ceased before 1805, and that at that date the forest 

 growth had been fairly started over small surfaces. By 1875 it had 

 extended over a surface of about 1,000 square miles.* 



*NOTE. — It seems appropriate in this connection to quote the following extract from 

 Mr. Fernow's annual report for 1888: 



" Blanford, who has recorded these observations in the above manner, adds that 

 these results, of themselves, are not proof absolute for the influence of forest preser- 

 vation, since possibly the earlier obscrvaiions were less reliable than the later, but 

 that these observations may be considered as addenda to the accumulating sigus of 

 the existence of such infliience on rainfall. 



"But even this method, which would class with my retail" methods, although 

 seemingly simple, before it can be admitted as conclusive, must, as the writer says, 

 be guarded by those special precautious which are demanded by strict scientific 

 inquiry. 



"The above figures were hailed wi(h satisfaction by those who are bound to prove 

 by statistics the forest influence on rainfall. 



" Unfortunately, as this report goes to press, their value is entirely vitiated by the 

 following statements made in the Indian Forester, January, 1889, which again ad- 

 monishes us to bo careful in placing too much weight on statistics. 



"Mr. Blanford, in order to assure himself of the value of the rainfall returns he 

 employed in the discussion of the Central Provinces, wrote to the chief commissioner 

 on the subject, to which the rejAy was received that ' the chief commissioner fears 

 that these records of rainfall previous to 188o can not be accepted as altogether reli- 

 able.' The commisioner explains the reasons why the records appear unreliable, and 



