SHELTER-BELT DEMONSTRATIONS ON THE GREAT PLAINS. 
21 
Table 7 shows the number of shelter belts planted by cooperators 
with trees furnished by the Northern Great Plains Field Station 
during the 5-year period from 1916 to 1920. inclusive. It also 
shows the number of the plantings made each year that were listed 
as successful on January 1. 1921. the number listed on that date 
as having failed, and the percentage of failures. In the five years 
1.234 plantings were made and at the end of the period 716, or 58 
per cent, of these were listed as successful and 518. or 42 per cent, 
as having failed. Almost exactly 50 per cent of the plantings made 
in each of the years 1916, 1917. and 1918 were listed as successful 
at the end of the 1920 growing season. 
--■y- = ; ^- 
Fig. 12. — Outline map of the Northern Great Plains region. Each township in which one 
or more plantings of shelter belts had been made in 1917 or in which application had 
been made for planting in 1918 is indicated by a dot. 
Failures may be and were due to any one or more of several causes. 
The more frequent causes have been improper planting, lack of care 
and cultivation, prolonged drought, and the owner leaving the farm. 
The years from 1917 to 1920. inclusive, were all years of severe 
drought over the greater part of the territory covered by the shelter- 
belt work. Such a succession of drought years is unprecedented in 
the time for which records are available. The work has consequently 
been in progress during the most unfavorable years it is likely to 
experience. Continued drought leads to economic stress which is re- 
flected on such projects as this either by abandonment of the farm 
or inability to properly care for and protect the plantings. Consid- 
ering the unusual stress of climatic and economic conditions, it is 
