DEFORESTATION IN SOUTH AUSTRALIA. 531 



the opposite view fi*om observations which they, of course, deem 

 equally convincing. Later meteorological observations, made by 

 men fully convinced of the absolute necessity for the most rigid 

 accuracy in all data of this description, have not hitherto been 

 productive of more than an uncertain sound on the question ; hence 

 it is that the exact position of forests as climatic factors is a problem 

 still awaiting solution. This is by no means the case, however, 

 with regard to the influence of forests on springs and other living 

 waters ; still more with reg^ard to the incalculablj^ important 

 function which they discharge in guarding the mountain ranges 

 from the erosion of their soil and svibsequent denudation, fiere we 

 can stand on firm ground, backed by well-authenticated facts. The 

 general position is this : Forest trees intercept the rain as it dashes 

 down and break the mechanical force of its fall, so that it finally 

 drops gently upon the ground beneath. While the trees thus 

 interpose themselves as a shield between the rain from above and the 

 soil below, the deposit of twigs, bark, leaves, rotten wood, and other 

 forest debris accumulated on the surface, it may be during the 

 course of generations, absorbs a large amount of the rain as it drips 

 from the trees ; of the remainder much is carried downward through 

 the innumerable channels offered by the millions of roots pene- 

 trating, otteu deeply, into the subsoil, leaving frequently but a small 

 l^ortion to flow off as surface water. Of this the force is broken, 

 the volume divided, and the rapidity checked by the numerous 

 obstacles existing on the forest floor in the shape of stems of trees, 

 trunks, stumps, and roots, of fallen timber, mosses, fungi, and 

 higher forms of vegetation existing more or less in all forests. The 

 water which sinks into the soil is ultimately delivered by the 

 processes of infiltration and percolation in a very gradual manner, at 

 various points, according to the geological formation of the district, 

 in the shape of springs. This, then, is the function discharged by 

 forests regarding the springs : — They prevent the rapid disappear- 

 ance of the rains in the short space of a few hours or days, and, in 

 the way indicated, regulate the delivery of the water so gradually 

 as to render the supply sufficient till reinforced by subsequent 

 rains. Respecting the power of the forest as a factor in regulating 

 the surface flow of storm Avaters, it mvist be borne in mind that 

 exceptional circumstances as regards the amount of rain precipitated, 

 the topography of the country, and character of the soil may 

 modify it to a certain extent ; but, while this is the case, the 

 important fact remains that the normal condition of forest soil, 

 anchored as it is by millions of roots, is proof against all attempts 

 at erosion, and defies the storm to tear it from its place or hurl it, 

 in the form of detritus, into the valley below. Forests, then, 

 j^revent the formation of torrents and the denudation of the area of 

 country on which they grow. 



Other influences of greater or lesser importance maybe attributed 

 to forests, but inasmuch as those specially indicated have the most 



