180 THE MANAGEMENT OF 



cultivated upon the principle which I have recom- 

 mended — namely, that of giving free air and room 

 — nearly three times the value of those which were 

 drawn up weakly. When oak trees have free room 

 for expanding themselves, the lower branches form 

 into bends for ship-building, which is a valuable 

 object; the trees also, being more branchy in 

 themselves, produce a greater surface for the pro- 

 duction of bark, and the bark itself, having free air, 

 becomes thick and heavy upon the tree. Indeed, 

 perhaps, it is not generally known that oak bark, 

 produced upon trees having free air about them, 

 weighs almost double that of an equal surface 

 taken from a tree confined and not having air ; 

 and at the same time, bark of such weight is always 

 more valuable, because containing a greater pro- 

 portion of tanning matter. 



What I have here said relative to the cultivation 

 of the oak, I regard as sufficient to convince any 

 proprietor of the necessity of keeping his oak forests 

 thinner of trees than any other of his woods : and 

 need only add, in conclusion, that in every other re- 

 spect oak plantations are to be managed upon the 

 same prmciples as other hard-wood ones. Oak trees 

 are never reckoned of full age till they have attained 

 from eighty to one hundred years ; therefore, after 

 a plantation of oaks has received its final thinning, 

 it should be allowed to stand until that age before 

 cutting down. 



