26 SHADE-TREES IN TOWNS AND CITIES 



grown so high as to completely hide the house from view. 

 The beauty of the Norway maples will increase with age and 

 add to the attractiveness of the house ; but in a few years 

 the poplars will have reached maturity and have begun to 

 decay. 



The wood of this species is very weak and extremely 

 brittle. In storms a great many limbs break and not only 

 disfigure the tree, but become a source of danger. The 

 tree sends out many roots near the surface of the ground, 

 that in time become so thick that they raise the flagstones 

 and crack concrete walks. The trunks also become so 

 thick at the base that they push the curbstones out of line. 

 The poplar belongs to the willow family, and, like the other 

 members of the group, loves water. If there is the slight- 

 est crevice in a sewer-pipe in the vicinity of a tree its fine 

 rootlets will penetrate the pipe and form a compact mesh 

 of fibers. In a short time this stops the flow of water. 

 Plate 6, Fig. 2, shows such a network of rootlets taken out 

 of a four-inch sewer-pipe. 



When in flower, fruit, or leaf, the Carolina poplar is an 

 undesirable object on a street. The flowers appear in March 

 and April before the leaves and, like those of the willow, 

 the staminate and the pistillate flowers are borne on differ- 

 ent trees. The staminate trees are densely covered with 

 aments four or five inches long, which ripen in a short 

 time, drop to the ground, and lie in heaps that make the 

 sidewalks slippery. The trees bearing pistillate flowers 

 mature their fruit in May. This consists of aments of 

 small capsules which, on maturing, split open and shed 

 a white, cottony mass of seeds. These fill the meshes of 

 doors and window-screens, and stick to the clothing of 

 passers-by. Pistillate trees when planted become an exas- 



