58 



ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 51 



Dutch elm disease and phloem necrosis are the most destructive 

 and widespread. Since hundreds of thousands of American elms 

 have been killed by these diseases in Illinois, many people are 

 planting other species for shade and ornamental purposes. How- 

 ever, the American elm is one of the most versatile trees. It is 

 easily propagated and transplanted, it grows rapidly, and it has 

 wide-spreading, high-arched branches desirable for specimen and 

 parkway plantings. The American elm and its varieties and the 

 winged elm are the only elms reported to be susceptible to phloem 

 necrosis. 



Asiatic elms, including Chinese and Siberian elms, the Chris- 

 tine Buisman elm, and the Bea Schwarz elm are resistant but not 

 immune to Dutch elm disease. The Christine Buisman and Bea 

 Schwarz elms are selections of U. carpinifolia. These resistant 

 elms can be planted in areas where Dutch elm disease abounds, 

 with assurance that they will persist indefinitely and be useful 

 for shade and ornamental purposes. The Chinese elm (U. parvi- 

 folia) (Fig. 57) is a slower-growing tree than the Siberian elm 

 (U. pumila) (Fig. 58). It has small, glossy, deep green leaves, 

 and sturdy branches which withstand wind and ice storms much 



Fig. 57. — Chinese 

 elm, with its small, 

 glossy leaves (inset), 

 is a sturdy tree. 



