7 o 



Yearboo^ of Agriculture 1949 



wind damage, but it is commonly used 

 as a shade and street tree. Its roots 

 commonly plug drain pipes. 



Other species sugar maple, Nor- 

 way maple, black maple, red maple 

 are usable only in the extreme eastern 

 border of the Plains area where rain- 

 fall is heaviest. 



THE RUSSIAN -OLIVE, an introduc- 

 tion from southern Russia, usually at- 

 tains less than 30 feet in height. It 

 survives well on many sites, from sandy 

 to alkaline soils, but prefers moist, rich 

 soil in open sunlight. It is drought- 

 hardy and moderately frost-resistant. 

 The dry, cast-off leaves sometimes are 

 eaten by sheep, goats, and cattle. Al- 

 though it is but little troubled with 

 insect or fungus attacks, it is suscep- 

 tible to cotton root rot. 



The Russian-olive merits wide use, 

 especially in the drier and more alkali 

 sections from the Dakotas southward. 

 It is not especially desirable as a street 

 tree, but if it is used in streets the lower 

 branches should be pruned when the 

 tree is young. 



THE AMERICAN SYCAMORE prefers 

 rich, moist soil, but it can adapt itself 

 to drier sites. It is not frost-hardy 

 enough for planting in the northern 

 Plains, but can be used in the eastern 

 part of the central and southern Plains. 

 Leaf blight, a fungus disease, is often 

 prevalent and causes considerable de- 

 foliation, disfigurement, and reduction 

 in growth. It is moderately resistant 

 to cotton root rot, and is the best of 

 the fast-growing tall trees for use on 

 soil infested with the disease. It is sus- 

 ceptible to chlorosis, however, on al- 

 kaline sites. It is recommended for 

 street planting in places free of blight. 

 The American sycamore is widely 

 planted as an ornamental. 



THE LONDON PLANETREE is less sus- 

 ceptible than the American sycamore 

 to leaf blight, but is more restricted in 

 range. It is best suited to the extreme 

 eastern edge of the Plains where rain- 

 fall is highest. It is excellent in parks. 



THE EASTERN BLACK WALNUT grOWS 



moderately fast and reaches a height 

 of 60 feet or more. On favorable sites 

 it will live 75 years. It thrives best on 

 moderately friable soil that has good 

 fertility and moisture. It will stand 

 some flooding but will not live long on 

 the swampy sites. Because its leaves 

 and fruit hulls contain tannic acid and 

 stain objects with which they come in 

 contact, the tree should not be planted 

 too close to walks or clotheslines. Sev- 

 eral insects attack the leaves and fruit 

 but do not endanger the health of the 

 tree. Fungus diseases are also of little 

 consequence. It is susceptible to cotton 

 root rot and is not drought-hardy. It 

 is used as a street and shade tree, but 

 the fruits are objectionable on streets. 



WEEPING WILLOW and black willow 

 are sometimes used as shade trees. The 

 European white willow appears to be 

 more drought-resistant than the other 

 species, but it should not be planted 

 on dry sites. 



The willows are all fairly short-lived 

 and subject to insect damage and fun- 

 gus diseases. 



Desertwillow, native to the South- 

 west, develops into a small tree 20 to 

 30 feet high under favorable condi- 

 tions. Often, however, it is shrublike, 

 especially in hedge plantings. It is ex- 

 tremely drought-hardy and prefers a 

 sandy soil. It will not tolerate flood- 

 ing and is short-lived probably about 

 20 years but withal it is an excellent 

 tree that can well be planted more 

 widely in the Southwest. Its principal 

 advantage over other species there is 

 its high resistance to cotton root rot. 



Other broadleaf species of local im- 

 portance that do well on sandy soils 

 and are usable principally in the south- 

 ern parts of the Plains are the western 

 soapberry (which is resistant to cotton 

 root rot), and Osage-orange and east- 

 ern redbud, both of which are prey to 

 cotton root rot. 



The principal value of evergreens 

 on the Plains is as ornamentals and for 

 protection from wind. They do provide 

 much shade, particularly when they 



