SHELTER-BELT DEMONSTBATIONS ON THE GREAT PLAINS. 17 



adopted of setting out a shelter belt of deciduous species as described, 

 above and later adding evergreens along the sheltered edge or inside 

 of the original planting. Care must be taken to leave a space of some 

 20 feet between the two plantings, or the small evergreens may suffer 

 from competition with the roots of the older planting for moisture. 



Figure 8 shows Scotch pine planted in 1920 and jack pine planted 

 in 1921 in east and west rows on the south side of the hardwood 

 shelter belt planted in 1916. This planting is near Isabel, S. Dak. 

 The photograph was taken in July. 1921. 



Fig, 11. — Box elder and green ash planted in 1918 in western North Dakota and aban- 

 doned to weeds after beinj? cultivated two years. Trees can not compete in this section 

 with annual weeds or perennial grass. 



DEMONSTRATION PLANTINGS. 



All of the planting stock used in these shelter-belt demonstrations, 

 except the Chinese elm, was grown either from seed or cuttings or 

 as transplants in the nursery at the Northern Great Plains Field 

 Station. Tables 3 to 6, inclusive, give the number and kind of trees 

 sent out for planting in each of the four States in the territory 

 covered by this work, during the 5-year period from 1916 to 1920, 

 inclusive. 



The shipments of each kind of stock to cooperators in each State 

 in 1916 are shown in Table 3. Shipments of planting stock totaled 

 701,911. A little over half of this number consisted of willow and 

 poplar cuttings which were made up of approximately equal numbers 

 of laurel-leaf willow, Eussian golden willow, Norway poplar, and 

 Carolina poplar. The summer season of 1916 was one of very favor- 



