DESCRIPTION OF TREES. 137 



abundant shade, and yet a chance for air to circulate freely 

 under its branches. It varies greatly in form, from the 

 broad round head to the very upright and strict vase form, 

 all of them, however, assuming more or less the graceful 

 arching growth. 



It grows to the greatest perfection in a deep, moist, 

 alluvial soil and is very easily transplanted. It is often 

 taken from the swamp or pasture and transplanted to the 

 open lawn or roadside with success, though nursery-grown 

 trees if tall and clean with the branches 10 to 12 feet from 

 the ground are more satisfactory. 



In training a young tree a forked growth should be 

 avoided, Fig. 24, and a single leading shoot encouraged 

 with lateral branches established at intervals on opposite 

 sides of the main trunk,, as in Fig. 18. If allowed to 

 make the forked growth, they are certain sooner or later 

 to be split down by the weight of snow or force of storms. 

 This should receive especial attention with trees taken from 

 the woods or roadsides, and cut back to the " bean-pole " 

 condition, as is often practised, and all of the lateral 

 shoots be kept headed back until the leader has full con- 

 trol, as in Fig. 23. 



SLIPPERY-ELM (Ulmus fulver). This species is of a 

 broader growth with larger leaves, but not quite the grace- 

 ful form of the white elm, nor is it quite so large, but a 

 valuable tree under some conditions. 



EUROPEAN ELM ( Ulmus cawpestris). More upright and 

 compact than the American species, and valuable where a 

 less spreading tree is desired. All of the elms are subject 

 to the attack of the elm-beetle, canker-worm, the elm-scale, 

 and other insects, and need close attention to prevent their 

 being seriously injured. See chapter on insects, page 261. 



