ADVANTAGES OF PLANTING. 17 



stmmental in enriching land still remains to be 

 noticed. When trees attain a certain size, they at- 

 tract multitudes of birds, which build their nests 

 and seek shelter among the branches. The dung 

 of these animals is the very richest kind of manure 

 which can be applied to land, and possesses, at least, 

 three times the strength of that commonly used in 

 agriculture. The quantity of it produced during 

 the long series of years which trees require to reach 

 maturity, is, especially where large colonies of crows 

 take up their abode, very considerable, and must 

 have a powerful influence in improving and ferti- 

 lizing the soil. Though scarce connected with our 

 subject, it may not be improper to remark here, that, 

 in trenching old woodlands, for the purpose of bring- 

 ing them under cultivation, what was formerly the 

 surface should still be kept uppermost, which may 

 be done by a very simple contrivance, otherwise the 

 part of the soil enriched in this manner will be bu- 

 ried too deep for the crop to reach it. 



I am aware it may be objected to all this, that 

 trees in hedge-rows about cultivated fields, are so far 

 from enriching land, that they render it very un- 

 productive for several feet on each side of them, as 

 many a farmer knows by dear-bought experience. 



B 



