570 



ON USEFUL AND 



BOOK I. 



of this kind to a grove, then the most suitable trees are to be 

 reserved at proper distances, and the rest grubbed out by the 

 roots : afterwards, the ground should have the necessary de- 

 gree of cultivation, until the trees can defend themselves from 

 cattle; when the whole may be sown with grass seeds. 



Resinous trees. — When an artificial plantation of the fir 

 tribe has remained without thinning for twenty years, the case 

 is frequently irremediable: about that age they are generally so 

 overpowered with one another, that they stop growing; and 

 whenever one is thinned out, all around it die. The best way 

 is to grub them all out by the roots, and replant, after the soil 

 is properly prepared by summer-fallow, or two or three corn 

 crops. Natural plantations of resinous trees, under twenty, 

 and artificial ones under ten years old, may most commonly be 

 much improved by thinning. In reclaiming plantations of re- 

 sinous trees, it is unnecessary to cultivate the soil, as their 

 shade destroys almost every other plant: often, indeed, culti- 

 vating the soil becomes hurtful to them, as their roots run so 

 near the surface, that they are liable to be much injured by the 

 operation. 



Hardwood and resinous trees mixed together. — 

 Few artificial plantations are entirely without resinous trees. 

 Here I refer to those where the number is so great, that they 



