RE-STOCKING DENUDED WOODLANDS. 195 



not much to fear, but if it is light and exposed towards 

 violent winds, something should be done to avert danger. 

 In this case, however, some transverse furrows would be 

 sufficient for this purpose. 



Upon a surface inclined twenty yards in the one hun- 

 dred (20 per cent.), the water after running about forty 

 yards will begin to loosen the soil and, according to its 

 being more or less compact, the erosion will be more or 

 less rapid. Then low-turfed earth walls should be built 

 strong enough to resist the pressure of the waters, but 

 allowing the flow over the tops without doing harm. 



If the slope is one of twenty-five yards to the one 

 hundred, the water after a run of twenty-five yards, digs 

 out ruts and loosens the soil. Then hedges or small 

 fences should be erected to stop the quickened water- 

 course, and to allow the formation of terraces by the soil 

 and cobble-stones accumulated behind the fences. 



When the soil has a slope of thirty yards in the one 

 hundred, it will be dug out by the water after an un- 

 checked flow of twenty yards, and the damming up 

 should begin at this point. With a declivity of forty 

 yards in the one hundred, the unchecked flow of water 

 should not be more than fifteen yards, and upon steeper 

 slopes the establishment of terraces should be more 

 narrowed down. 



The diagrams on pages 196 and 197 show the different 

 kinds of dams, dikes and fences which are to be built 

 in order to check the rapid flow of mountain waters. 

 The material to be used depends much upon that *rhich 

 is found in localities where it is to be utilized. 



In order to preserve these expensive means, which are 

 both preparatory and protective to tree-growth for all 

 times to come, the terraces created by the accumulation 

 of stones and earth should be consolidated by sowing 

 grasses and planting quick-growing coppice wood. 



