44 TREES AS GOOD CITIZENS 



Una Poplar is one of the worst offenders. Its brittle 

 quality causes limbs to break, while its bulging roots and 

 trunk mar the evenness of curb and sidewalk and cause 

 cracking of concrete or flagstones; and the dropping of 

 spring blossoms is so extensive as to become a nuisance. 



Silver Maples break sidewalks through the action of 

 their roots, and have disadvantages similar to those of the 

 Carolina Poplar. The staminate (male) Ailanthus is 

 objectionable to many because of the unpleasant odor of 

 its flowers, and care should be taken to use only pistillate 

 (female) trees, the flowers of which lack this odor. Only 

 the staminate or non-fruit-bearing form of the Ginkgo 

 should be used as the falling fleshy fruits not only make 

 the pavement slippery, but are somewhat poisonous 

 to the skin of some people. The Cottonwood spreads 

 its seeds in the form of a fine cotton or down which 

 is quite objectionable because it is often irritating to the 

 respiratory organs and is most untidy. It can be avoided 

 by using staminate trees only. As Poplars are grown 

 from cuttings, trees of the desired sex may be obtained by 

 making cuttings from trees of that sex. Root cuttings 

 from an ungrafted tree of the proper sex could be used for 

 propagating the Ailanthus, but the Ginkgoes would have 

 to be grafted. 



A final consideration, but by no means the least 

 important, is the element of beauty. This involves form, 

 vigor and suitability to location and environment. 

 Factors of beauty also include the coloring of the leaves 

 and the nature and appearance of flowers or fruit. Fine 

 examples of coloring are to be found in the brilliant 

 autumn foliage of the Red Oak, following its summer 

 dress of heavy dark-green leaves. The gorgeousness of the 

 Maples in autumn coloring makes these trees general 

 favorites for street planting. Of the Horse Chestnut, the 



