50 



A horticultural variety with a nar- 

 rower, more upright crown is some- 

 times grown successfully under such 

 conditions. Because the thick shade and 

 mass of fine feeding roots of the Nor- 

 way maple make it hard for grass to 

 grow under the tree, Norway maple 

 frequently is considered undesirable as 

 a lawn tree. 



The Schwedler maple, a variety of 

 Norway maple, has a similar type of 

 growth. When young, it has bright-red 

 leaves that change to dark red and 

 finally to green. It is planted on lawns 

 and sometimes along suburban streets 

 for ornament and for shade. 



The Norway maple is subject to 

 about the same pests as the sugar 

 maple, but is less subject to leaf scorch. 



Red maple, a native, is less desirable 

 for a shade tree than either the sugar 

 maple or the Norway maple. It can be 

 used when a fast-growing tree is 

 needed. The red maple develops a 

 conical or broad, rounded crown, with 

 bright-green leaves that assume bril- 

 liant shades of orange, red, and scarlet 

 in autumn. The foliage casts a moder- 

 ately dense shade. In the spring, masses 

 of red flowers make it attractive. 



Red maple is easily transplanted. 

 The wood is somewhat weak and sub- 

 ject to storm damage, and its roots 

 often enter and clog sewers. 



THE ELMS are outstanding trees, but 

 unfortunately the American elm can- 

 not be recommended now except for 

 limited planting, because of phloem 

 necrosis and the Dutch elm disease, 

 both of which are spreading rapidly 

 and causing heavy losses. New public 

 plantings of American elm should be 

 delayed therefore until satisfactory 

 control measures for the diseases have 

 been developed, and the home owner 

 will do well to consider carefully 

 whether some other kind of shade tree 

 cannot be planted instead. 



In the Northeast, the Dutch elm 

 disease extends from the Atlantic sea- 

 board westward to Indiana. An iso- 

 lated outbreak has been found in 

 Colorado. It has not been found in 



Yearbook, of Agriculture 1949 



Maine, New Hampshire, Michigan, 

 Wisconsin, Minnesota, Illinois, Iowa, 

 Missouri, or Arkansas. 



Phloem necrosis is not known to 

 occur in Pennsylvania, States east of 

 the Appalachians, or in Michigan, 

 Wisconsin, and Minnesota. The Ameri- 

 can elm is subject to several other pests. 



The American elm grows to a height 

 of 50 to 100 feet and has a tall, branch- 

 ing trunk. It develops numerous as- 

 cending or drooping branches that 

 form various types of crowns, such as 

 the typical vase or umbrella forms. 

 The beauty of its various forms of 

 growth and the arching of its branches 

 above the streets of New England 

 towns have made the American elm 

 an outstanding characteristic of the 

 landscape. None of the many intro- 

 duced species of elm can equal it for 

 ornament or shade. The greenish flow- 

 ers appear in drooping clusters in April 

 or May before the leaf buds open. The 

 leaves are 4 to 6 inches long, rough, 

 dark green, unequally rounded at the 

 base; they turn yellow in autumn and 

 usually fall rather early. 



The American elm is easily trans- 

 planted, grows rapidly, and often lives 

 between 70 and 100 years under city 

 conditions. Tfye American elm is tol- 

 erant of a wide range of soil condi- 

 tions, except dry, sandy locations, but 

 its best growth is developed in moist, 

 well-drained soils. In its natural habitat 

 it is found along streams or in low, 

 moist ground. It grows well on streets 

 and in yards. The growth habit of the 

 branches is such that the crotches of 

 old trees often have to be braced in 

 order to withstand heavy wind or ice 

 storms. 



The rock elm might be used more 

 for streets and lawns, as it is a large, 

 strong, narrow-headed tree. This elm is 

 more suited to the northern than to 

 the southern part of the region, and 

 should be considered particularly for 

 the Lake States. Rock elm grows more 

 slowly than American elm. 



In this region two European species 

 of elm are grown sometimes as shade 

 trees. They are susceptible to the Dutch 



