38 ELEMENTS OF SYLVICULTUEE. 



caked ; the dead leaves are blown away and this 

 essential covering to the soil, which must be kept 

 free and rich, is hence lost. 



In the second place when we destroy the leaf- 

 canopy in a crop which consists of high poles, all the 

 above disadvantages are incurred and, in addition, 

 owing to the greater height of the trees, the wind 

 may commit serious havoc ; in the case of certain 

 trees, especially the oak, the bole, already of a good 

 height, will become covered with epicormic branches, 

 which give rise to knots that depreciate the 

 value of the timber, as it cannot then be employed in 

 cooperage and other trades which require split 

 wood ; but the principal danger of these epicormic 

 branches lies in the fact that they forcibly entail 

 the decay of the crown, cause faults in the heart- 

 wood resulting from dead branches, and sometimes 

 occasion the death of the tree itself. 



Lastly, as the forest grows old, the chief danger 

 to be feared in isolating the crowns, is the creation 

 of gaps by the wind, which go on ever getting larger 

 and larger ; the soil deteriorates more and more, 

 and becomes unfitted for natural reproduction. If 

 this fault has been committed, the most fortunate 

 thing that can happen is for a crop of young seedlings 

 to come up without delay. This will at least have 

 the effect of protecting the ground and preserving 

 its moisture and fertility. 



Not only must the leaf-canopy never be inter- 

 rupted in executing a thinning, but in direct 

 opposition to what holds good for regeneration 

 cuttings, the small shrub vegetation must be 



