8 BULLETIN 1113, U. S. DEPARTMENT OF AGEICULTURE. 



It is rarely found growing very far from the moist bottom lands 

 and does not push its way up the dry coulees toward the prairie 

 levels. It is, however, a very useful tree for prairie planting, 

 adapting itself readily to upland conditions, and has been known 

 to persist in sod for a number of years after attaining reasonable 

 size under cultivation. It may be classed as one of the best for 

 shelter-belt planting in all types of soil throughout the entire region. 



Green ash. — The green ash [Fraxinus lanceolata) is found in 

 much the same range as the box elder. It prefers somewhat drier 

 sites and often works its way up the long open coulees to the level 

 of the prairie. In these situations it is frequently mixed with white 

 elm, June berry, wild plum, buffalo berry, and chokecherry. It 

 ranks with the box elder as one of the best trees for shelter-belt 

 planting, doing well on all types of soil except sand and gravel, 

 and it shows a marked ability to live through periods of extended 

 drought. 



White elm. — The white elm {Ulmus americana) though generally^ 

 considered a moisture-loving tree, is found in company with the 

 green ash and buffalo berry in such comparatively dry situations as 

 open valleys far removed from running water. Here it maintains 

 itself in sod on the sides of dry runs. This occurs more generally 

 at the western limit of its range, which is in eastern Montana and 

 the Black Hills of South Dakota. In the Plains region it departs 

 somewhat from its usual graceful shape, old trees at a distance 

 resembling gnarled oaks. It is a good tree in shelter-belt plant- 

 ings, showing a preference for clay soils. It is difficult to get seed 

 for propagation, as the blossoms are often injured by the late spring 

 frosts. 



Western cottonwood. — The western cottonwood {Populus deltoldes 

 var. occidentalis) is the dominant tree species along the larger river 

 valleys of the Great Plains where it often attains great age, form- 

 ing extensive open groves. It grows at some distance from its 

 usual bottom-land habitat and may occasionally be found far up 

 some dry run. It is a very good tree in shelter-belt planting 

 throughout the area east of the Missouri Eiver; farther west, how- 

 ever, it does not succeed as well. It adapts itself to either sand 

 or clay soils, but is not to be recommended for dry situations. 



Balsam poplar. — The balsam poj)lar {Populus halsamifera.) is 

 found in the Black Hills in South Dakota; the Turtle Mountains,, 

 the Mouse Eiver Valley, and on lake shores in the Coteau du Mis- 

 souri in North Dakota ; and possibly in the Little Kocky Mountains 

 and the Sweet Grass Hills in Montana. The tree has not been 

 planted for shelter-belt purposes except in a limited area south of 

 the Turtle Mountains in North Dakota. As it is essentially a 



