138 FOREST LAND, 



be supposed that, under a system of over-crop- 

 ping, or as in Scotland it is emphatically 

 termed a scourging system, it will not at 

 length give way, and when its impoverishment 

 once takes place, they may be assured it will 

 be a matter very difficult, or it may be im- 

 practicable, to restore it to anything like ori- 

 ginal fertility. 



This observation more particularly applies 

 to land which has been reclaimed from forest. 

 Alluvial soil by deeper and deeper ploughing 

 may be kept in a productive state for a longer 

 time, and when it sickens, as sicken it must, 

 from constant working without feeding, it may 

 perhaps be revived by stimulating manures, or 

 by being laid to rest for a sufficient time un- 

 der grass. Even in this case, prevention be- 

 ing better than cure, it were unwise to dete- 

 riorate the soil by overcropping when the 

 means of preserving its fertility are at hand. 



But as to land cleared from forest, the pro- 

 ductiveness of it seems to depend entirely on 

 a covering of vegetable earth, which, in its forest 

 state, had, for perhaps thousands of years, been 



