COPPICE WITH STANDAEDS. 139 



spare crowns and the fact that the action of cover 

 is not felt equally over the whole horizontal surface 

 of projection, it is admitted that the cover of first 

 class reserves is not injurious. For this reason the 

 question as to number of trees to be reserved can 

 concern only the other classes, and especially those 

 which have lived more than three rotations, the 

 crowns of which are not only broader but a great 

 deal deeper. Before calculating the extent of surface 

 which ought to be covered by the reserve, even before 

 inquiring into the circumstances which, in a general 

 way, permit of the reservation of a greater or smaller 

 number of standards, it is useful to have clear 

 notions on the action of cover. 



As we have seen in the definitions, the word cover 

 expresses sometimes the horizontal projection of the 

 crown of the tree, sometimes the action itself exerted 

 by the crown on that area. This action is always 

 injurious, because the direct rays of light are inter- 

 cepted, the formation of dew prevented, and the 

 equal distribution of rain rendered impossible. But 

 in the first place cover does not always act with the 

 same intensity, and in the second place its effect is 

 not felt equally on the whole surface of projection of 

 the crown. With equal areas, the intensity varies 

 with the species, and for one and the same species 

 with the thickness of the foliage and length of bole. 

 When the bole is of sufficient length, the effect of 

 cover may be rendered insignificant. We have a 

 proof of this in the seedlings which come up and 

 grow under a complete canopy of lofty trees. 



It is therefore clear that the lighter the cover of 



