84 LEAF CANOPY AND PBUNING. [Dec, 



LEAF CANOPY AND PBUNING. 

 I. 



EAF canopy producing shade in a covert is attained when the 

 crowns or leafy tops of the trees in a state of rest touch one 

 another or interlace. The shade is more or less thorough 

 according to the completeness of the canopy and the denseness of the 

 foliage of the various kinds of wood. Where complete and unbroken 

 leaf canopy is maintained and the kind or kinds of wood afford 

 sufficiently dense foliage to intercept the sun's rays, a process of 

 natural pruning or suppression of lower branches goes on under the 

 shade, which renders artificial pruning in a great measure superfluous. 

 If, on the other hand, the trees are kept so far apart that their 

 canopy is discontinuous or interrupted, there will be more need for 

 artificial pruning with a saw or sharp instrument, in order to give the 

 trees length of bole and a desirable form. Tiie maintenance of com- 

 plete leaf canopy taxes the dexterity and forethought of the forester 

 to the utmost, as may be gathered from Bagneris' ' Sylviculture,'* in 

 chapter second, on the application of the method of thinnings to the 

 principal forest trees, and elsewhere throughout the work. The 

 advantages accompanying or derived from complete leaf canopy are 

 many and various. Some of them may be enumerated as follows : — 



1. The ground is sure to be completely stocked with as many trees 

 as there is room for. 



2. The degrees of moisture of the soil are equalised and favourably 

 modified at all seasons. The stored-up moisture is preserved against 

 the action of the sun and wind in summer and in seasons of drought. 

 In winter, on the contrary, and in wet seasons, a complete canopy of 

 branches and twigs or spray among deciduous trees, or of fohage 

 among evergreens and needle woods, intercepts a considerable 

 (quantity of atmospheric moisture and keeps it from over-saturating 

 the ground. 



3. A greater quantity of leaves and spray is yielded to manure 

 the ground, and distributed in annual layers evenly over the floor of 

 the covert. 



4. The shade of leaf canopy usefully moderates ami retards the 

 decay of the fallen leaves and organic refuse. 



5. The svm's rays being intercepted, the growth of weeds and 

 grasses is prevented or checked. 



6. Leaf canopy being necessarily accompanied by a rather close 

 juxtaposition of the trees, the action of violent winds is tempered, 

 and they are hindered from carrying away leaves and useful gases. 



* "Elements of Siilviculture ^ Price 55,, London, William Bidcj- cC- Son, 14, 

 Bartholoviev) Close, E.G. 



