Pruning and Trimming 83 



growing naturally in the swamp promise well. In addi- 

 tion, a certain space, say one and one-half by two yards, V^ 

 should, if practicable, be left unpaved around the base of 

 the tree, and this space should be kept open, stirred and 

 fertilized from time to time. Where this is not practicable, 

 a smaller space left unpaved may be covered by a grill or 

 iron grating, supported on wooden pegs dri\"cn in the ground. ' 

 Such grills are found in Paris, Berlin, and London (see 

 page 119), and permit of watering the trees. This treat- 

 ment is, to be sure, applicable only with new plantings, 

 when the trees will adapt themseh'es to the conditions. 

 Where old established trees are concerned, it is doubtful 

 whether they can be permanently maintained when a tight 

 pavement is placed over their roots. 



Pruning and Trimming. Next in importance to atten- 

 tion to soil conditions, there is nothing of more value for 

 avoiding and correcting trouble in tree economy than prop- 

 erly applied surgery. 



There is competition cver}-Avhere in the living world, 

 and not only do the individual trees compete with each 

 other for root and air space, water and light, but each leaf, 

 each bud, each shoot competes with its neighbor, although 

 only a limited number can develop. 



As we have seen, trees prune themselves, i.e., some of 

 the buds and branchlets die every year and are broken off 

 by the wind. This natural pruning is the result of the 

 struggle for existence, i.e., for food and light supply, between 

 the buds or branchlets, and an adjustment in the economy 

 of the tree, keeping the balance between income and expend- 

 iture. By reducing the number of mouths to be fed the 

 remaining are belter fed. There is, therefore, not neces- 

 sarily any apprehension to be had if some twigs and branches 

 die in response to the perfectly normal need of adjusting 



