Timbers. 



220 



[March, 1912. 



that evaporation inside a forest is half 

 that which proceeds outside, and conse- 

 quently a large amount of moisture is 

 retained for future use. Notwithstand- 

 ing what appeared to be overwhelming 

 evidence to the contrary, however, 

 the Weather Bureau of the United 

 States issued a statement some time ago 

 that ploughed fields will hold water 

 quite as well as the ordinary mould of 

 forest, and that it is believed that there 

 is no evidence that deforestation has 

 ever augmented droughts. In order to 

 controvert this statement the writer in 

 the Indian Forester marshalls evidence 

 which appears to be irrefutable. He 

 explains at the outset that by drought he 

 does not mean failure of the rainfall 

 but rather the failure of the water- 

 supply, whether it is derived from wells, 

 springs or rivers. Mr. Curtis Guild, an 

 eminent authority in the United States, 

 declares without hesitation that the 

 experience of China, France, and of 

 Spain is that the denudation of forest 

 clad hills has led to a succession of 

 freshets and droughts on what were 

 once fertile slopes, and, save where re- 

 forestation has been carried out, lms 

 reduced the agricultural population by 

 sweeping away the very soil itself. 

 Observations made by Mr. de Rothen- 

 bach, director, of the water service of 

 the city of Berne, show that the springs 

 from which the supply is derived are 

 sheltered by a mass of forest. The con- 

 sequence is that the springs have a 

 regular and constant flow and during 

 dry seasons the forest gives out slowly 

 the water that it has stored up during 

 the raius. Professor Huffel again des- 

 cribes in his " Economic Forestier " ex- 

 periments conducted by the Swiss 

 central station of forestry research with 

 the object of comparing the flow of two 

 water-courses, one emanating from a 

 basin containing only eighteen per cent, 

 of forest area, and the other with a 

 forest area of ninety-one per cent. It 

 has been verified as the outcome of the 

 investigations, first, that at the time of 

 the maximum of high water the channel 

 of the deforested region carries 30 to 50 

 per cent, more water per unit ot surface 

 than the wooded region. The next propo- 

 sition established is that after dry 

 periods of long duration, the springs of 

 the deforested region dry up completely 

 and the bed of the stream becomes dry, 

 while, on the other hand, the stream 

 from the forest region gives at least five 

 litres of water per second. There is 



much more evidence from Europe, but 

 it will be of more interest to examine 

 the results of the enquiry lately held at 

 the instance of the Government of India 

 into the influence of forests on water 

 supply in this country. The investi- 

 gation has not been carried out for a 

 sufficient period of time, but a number 

 of notable facts have been brought to 

 light. In Berar, for example, the des- 

 truction of forests in the Melgkat has 

 necessitated the stills used for the ex- 

 traction of Rusa oil being located lower 

 down the stream, in consequence of the 

 lack of water at the spots where they 

 were previously placed. A number of 

 statements bearing on the theory that 

 forests have an important effect on the 

 area available for cultivation are forth- 

 coming from Burma, while a comparison 

 has been effected in Bengal between two 

 rivers, the one flowing through a forest 

 area and the other with its catchment 

 area deprived of protective verdure. 

 These rivers are the Koina and Rora in 

 Singbhum, both 30 to 45 miles in length. 

 The Koina drains an expanse of country 

 of which 80 per cent, is reserved forest, 

 and it holds a plentiful supply of water 

 throughout the year. The Rora, on the 

 other hand, passes through a region 

 which has been almost entirely denuded 

 of trees, with the result that its water 

 runs low in the winter and in the hot 

 weather disappears. The committee ap- 

 pointed in 1908 to report on the denuda- 

 tion of forests in Chota Nagpur and 

 Orissa, again showed that there had 

 been deplorable destruction of forest in 

 Manbhum, Ranchi, Singbhum, Sambal- 

 pur, and Orissa, which was secured by 

 over-exploitation by contractors, exten- 

 sion of cultivation, wasteful and reckless 

 cutting by villagers, fires, and over- 

 grazing. The Committee found that the 

 subsoil water level is very low in most 

 parts of Chota Nagpur, and in Ranchi 

 wells 40 to 50 feet deep dry up at the be- 

 ginning of the hot weather. In the 

 opinion of the investigating body, more- 

 over, it was proved that the streams in 

 Government Forest reserves last longer 

 through the dry season than streams of 

 similar size in denuded areas. In view of 

 these facts and of the other evidence 

 adduced, the writer of the article is fully 

 justified in n*aintaining " that forests do 

 play an all-important part in preserving 

 moisture and in ensuring an equable flow 

 in springs and rivers," and that their 

 destruction leads to results of a most 

 undesirable character. 



