100 



Cougress at Milan iu which Wolfschiitz of Briinu gave proof to show that 

 the efficacy of the forest in retarding water fails in times of long-continued 

 and extraordinary rain, and Honsell claims that the best wooded basins 

 of the Black Forest, Harz, Spessart, etc., contributed most of the water 

 of the floods of the Rhine in 18S2. Like experiences were reported from 

 Ihe watersheds of the Elbe in 1897, of the rivers Enns, Traun and Ybbs in 

 1899, and from the densely forested Riesenwald in Silesia in ISSS, 1897 

 and 1903. Wolfschiits, however, thinks that forests have a limited and 

 local influence in certain regions in reducing floods. Lauda, director of 

 the Austrian Ilydrographic Bureau, comes to the conclusion that weather 

 conditions preceding the nrecii)itatiou has a bearing on forest influences, 

 the forest ha^ ing the gi-eater i-etentive capacity after a drouth. Ponti, 

 an Italian engineer, asserts experiences of increased floods due to de- 

 forestation in Sardinia, Sicily, and Canipobasso, and of the watersheds of 

 Aflda and Matero. lie also finds favorable influences from forest planting 

 in several provinces. The Russian, Lokhtine, cites a long series of gen- 

 eral experiences and observations from parts of Europe and especially 

 from Russia which indicate injurious effects from deforestation. Other 

 instances were given which sliow that the water level is decreasing with 

 deforestation. 



After considering these and much additional testimony on the subject, 

 one is justifietl in saying that forests do act as great regulators of rain- 

 fall but that their value in this resjiect is a relative one which is motlified 

 by many conditions. 



F(U!i:sTS AM) W.\ii:r I>Evr',r,. 



Let US now consider the rclatidu of forests and water level as shown 

 by observations and experiments. 



Professor Biihler [see (7)1 found a much lower ground water level 

 imder forest growth than in the meadows. Ototsky in the steppes of 

 Russia, where a low rainfall prevails, came to the same conclusion as 

 Biihler. Ebermayer and Ilartman in Bavaria, however, found no differ- 

 ence between the ground water level of forest and field. Otoski states 

 that Wollny and King found the ground water level lowered by a forest 

 and that this caused its lowering in adjacent open soil. . In a bulletin 

 by A. Tolsky and E. Henry (10) it is shown that observations made inde- 

 pendently in France, near Nancy, and those made in the Russian Steppes 



