328 



Bulletin" 2^6. 



The amount of pruning required by trees on city streets and country 

 highways is comparatively small. Pruning is necessary^ however, in 



veiy young trees that are establishing their form, and 

 in old specimens that must be rejuvenated by arti- 

 ficial means. Young trees are usually vigorous and 

 rapid growers, and the least influence may produce a 

 strong or weak growth which may greatly affect the 

 form of the mature tree. Especial care is necessary 

 in the case of specimens collected from the woods, 

 and of nursery stock which has not been trained cor- 

 rectly. The main attention required by young trees 

 is to remove crowding branchlets, to cut back over- 

 vigorous growths, and to en- 

 courage an upright growing 

 shoot called a leader, all of 

 enhance the natural beauty 



Fig. 246. — The in- 

 correct way in 

 which to remove 

 large branches. 



Fig. 248. — A "monument 

 to the memory of the 

 pr liner," and a common 

 disfiguration on onr 

 shade trees. 



which aims to 



of the specimen. 



Young elms perhaps require as much pruning 



as do any other species of street trees. Uni- 

 formly developed specimens of these trees may 



be selected from the nursery, and yet when 



transplanted in an avenue they will soon show 



their characteristic uneven development in both 



form and size. They should be so trained that 



the broad and strong forks will be developed in 



preference to the narrow 

 and weak ones, in order 

 to avoid the liability to subsequent splitting. 



Season for pruning. The correct season to prune 

 trees cannot always be definitely set. The time for 

 pruning street trees may cover a wider range than 

 does that for pruning certain ornamental trees and 

 shrubs in which the season for producing flowers 

 must be considered. The difference lies in the differ- 

 ences in the purposes for which the pruning is done. 

 While pruning may be performed at almost any 

 season of the year, yet pruning in the summer 

 months is attended with numerous difficulties. The 

 most advantageous seasons for this work are in the 



early spring, previous to the beginning of the growing period, and the 



late summer or autumn. Of these two, the time between late February 



Fig. 247. — The cor- 

 rect way in which 

 to saw a limb to 

 prevent splitting. 



