308 



The Farm Woodlot 



EROSION. FIG. 61 



We have seen how the forest cover prevents rapid 

 surface run-off, conserves the rainfall and consequently 

 regulates the flow of the streams. What happens when 



FIG. 61. Land badly eroded as result of clearing and cultivation. 



the forest is cut away ? The removal of the shade opens 

 up the ground to the direct insolation and more open 

 circulation of the wind. The humus and leaf mold 

 which was kept always moist in the sheltered shade of 

 the forest is now exposed to alternate wetting and drying. 

 Under these conditions it decays very rapidly, all its vege- 

 table structure disappears, the leaves and twigs are re- 

 duced to fine mineral particles and the bare soil is exposed 

 to the driving wind and rain. There is no longer any 



