10 BULLETIN 1113, U. S. DEPARTMENT OF AGRICULTURE. 



Cottonwood {P. deltoides). It has not yet been tested throughout 

 the Great Plains region as a shelter-belt tree. 



Narrow-leaved cottonwood. — The narrow-leaved cottonwood {Pop- 

 ulus angustifolia) prefers moister situations than its related species, 

 and clings closely to the river and creek margins and low flood lands. 

 It is a Rocky Mountain species, having a range much more restricted 

 than the acute-leaved poplar. It has been planted as a street tree 

 within its range, but it makes a poor showing for this purpose. 

 Its usefulness for shelter-belt planting is doubtful. 



Diamond willoiv. — The diamond willow {Sallx mackenzieana) is 

 found generally throughout the Great Plains area. It follows the 

 river and creek bottoms to the foothills of the Rocky Mountains. It 

 is a tree of some economic importance as a source of fence posts. It 

 has been planted in shelter belts on the prairie with only fair suc- 

 cess. 



Bur oak. — The bur oak {Quercus macrocarpa) is found as far 

 west as the Black Hills and in the Bad Lands of western North 

 Dakota, southeastern Montana, and northeastern Wyoming. It 

 grows on .the drier sites along stream banks and old flood plains, 

 occasionally venturing to the lower prairie levels. It does not grow 

 to a great size, though specimens are found of apparent great age. It 

 has not been considered a practical tree for transplanting to shelter- 

 belt sites. 



CTwkecherry. — The chokecherry {Prunus virginiana) ranges 

 throughout the entire Great Plains region along the river courses 

 and up the dry coulees to the prairie levels, where it is often found 

 associated with the green ash. It is well adapted for shelter-belt 

 planting, doing well in all situations except very sandy or low wet 

 soils. 



Buffalo herry. — The buffalo berry, or buUberry {Shepherdia 

 argentea) , is closely associated with the chokecherry in range and 

 adaptability for shelter-belt planting. It is more suited to the sandy 

 types of soil, but does not favor low wet situations. 



CONIFEROUS OR EVERGREEN SPECIES NATIVE TO THE REGION. 



Black HiUs spruce. — The Black Hills spruce {Picea canadensis) .^ 

 a form of white spruce -found in the Black Hills of South Dakota, 

 has certain characteristics which distinguish it from the common 

 white spruce of northern Minnesota and Canada. It is not exacting 

 as to soil types, but prefers the drier locations. It is one of the best 

 evergreens for shelter-belt planting in the northern Great Plains. 



Figure 5 shows spruce on the east side of the deciduous shelter belt 

 at the Northern Great Plains I ield Station, Mandan, N. Dak. The 

 three rows from left to right are blue spruce, white spruce, and Black 

 Hills spruce. The relatively greater size of the Black Hills spruce 



