14 BULLETIN 1113, U. S. DEPARTMENT OF AGRICULTURE. 
shown to winterkilling and drying out for lack of moisture. In cer- 
tain sections it has made an excellent growth, but it can not yet be 
recommended for general use. 
CONIFEROUS OR EVERGREEN SPECIES INTRODUCED TO THE REGION. 
Scotch pine. — The Scotch pine (Pinus sylvestris) is a native of 
northern 'Europe and Asia and has been widely planted in the United 
States. It grows successfully on the prairies east of the Great Plains 
region, and recent plantings within the region indicate that it is one 
of the best evergreens for shelter-belt use. It is not as well adapted 
to sand and gravel soil as the jack pine and does not do well in moist 
or low, wet situations. 
Jack pine. — The jack pine (Pinus divaricata) is found extensively 
on the more sandy soils of northern Minnesota. It is adapted to 
shelter-belt planting on the Great Plains, especially on sandy soil. 
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Fig. 8. — A shelter belt near Isabel, S. Dak. In the foreground are Scotch pines planted in 
1920 and jack pines planted in 1921 in east and west rows on the south side of the 
broadleaf section planted in 1916. Photographed in July, 1921. 
It does not do well on clay soil and should not be placed in moist or 
low, wet situations. 
White spruce. — The white spruce (Picea canadensis) has a wide 
range in northern Minnesota and Canada. It is adapted to shelter- 
belt planting on the Great Plains and is suitable for practically all 
types of soil. It will grow in either wet or dry situations. 
Blue spruce. — The blue spruce, or Colorado blue spruce (Picea 
parryana) , is native to the Rocky Mountains of Colorado, Utah, and 
Wyoming. It appears to be perfectly hardy when planted in shelter 
belts in the northern Great Plains. It is more exacting as to soil 
requirements than the white spruce, showing preference for clay 
soils. 
TREES IN RELATION TO SOIL TYPES. 
Not all species of trees adapted to this region grow equally well on 
the same type of soil. The typical shelter-belt planting site is on 
the open upland prairie where the soil texture falls into the general 
