128 SHADE-TREES IN TOWNS AND CITIES 



ning is neglected the problems of restoring trees to sym- 

 metry, of suppressing certain branches, and of forcing 

 others become very difficult. Not all trees have the 

 same power of sending out new shoots when branches 

 are cut back. Rapidly growing trees, like planes, soft 

 maples, elms, and poplars, lend themselves more readily 

 to heading back than other trees. One of the advantages . 

 of the use of the planes as street-trees is that they recover 

 quickly from the effects of severe pruning. 



When trees are cut back, numerous shoots develop from 

 buds near the ends of the remaining branches. Plane-trees 

 especially send out a whorl of new twigs. Two or three 

 years after heading back, it is necessary to suppress or 

 entirely remove some of these new branches, and leave only 

 the more vigorous ones to maintain the growth of the top. 

 Figs. 21 to 24 show the various steps in the process of res- 

 toration of an old oriental plane that had become denuded 

 at the base. 



An instrument called a dendroscope. Fig. 25, devised by 

 Des Cars,' is sometimes helpful when shaping or heading 

 back a number of trees to the same form and dimensions. 

 It consists of a piece of thin paper or wooden board, about 

 4x8 inches, in which is cut an opening proportional in out- 

 line to the form it is desired to give the trees. With this 

 device the foreman can indicate to the pruner in. the tree the 

 exact places where cuts should be made. 



The foreman stands removed from the tree at a distance 

 about equal to its height, holds the dendroscope vertically 

 and at such a distance from the eye that when he looks 

 through the opening, the bottom of it coincides with the base 

 of the tree and the top with the place marking the height to 



' "A Treatise on Pruning Forest and Ornamental Trees," by A. Des Cars. 



