46 ELEMENTS OF SYLVICULTUEE. 



be grown to seven or eight feet in girth without 

 decay of the heartwood, they must be allowed to reach 

 at least these dimensions before they are felled. To 

 obtain such trees in high forest, it is necessary to 

 adopt rotations of from 160 to 200 years according 

 to the fertility of the soil in each case. 



KEGENEEATION. Pure oak is always harder to 

 deal with than when it is associated with other 

 species ; the produce of a pure oak forest is of less 

 general use ; the wood is too soft ; moreover it is 

 very seldom that pure oak is found naturally over 

 large tracts of country. Nevertheless as this state 

 of things does sometimes occur, whether in the 

 course of nature, or as the result of ill-advised opera- 

 tions, we must investigate the rules that are 

 applicable both to the regeneration cuttings and to 

 the improvement cuttings, only we will take the 

 opportunity of pointing out the advantages of the 

 association of oak with other trees, and will at the 

 same time indicate the rules to follow in the latter 

 case. 



PEIMAEY CUTTING. Because the acorn is heavy, 

 but chiefly because the soil must be kept moist and 

 free from long grass and brushwood, the primary 

 cutting must be made close. To ensure the preser- 

 vation of the seed until the following spring, and to 

 assist its germination, it is especially important to 

 clear the ground of all brushwood, and to leave as 

 reserves, trees with a lofty bole. If this latter 

 condition cannot be realised, because the forest has 

 been too thinly stocked in past time, it will be a 

 judicious step to prune away the lower branches, 



