24 



BULLETIN 1113, U, S. DEPARTMENT OF AGRICULTURE. 



est percentage of stand was 84.8 in 1920 and the lowest 59.4 in 1919, 

 The high percentage of stand in 1920 was at least partly due to the 

 fact that only species that had proved hardy and easily established 

 were used, while both willow and poplar are found in preceding 

 years. The rainfall in 1916 was above normal, and in the four suc- 

 ceeding years it was below normal. The effect of the continued 

 drought on the establishment of willow is clearly shown by the poor 

 stands in 1918 and 1919 as compared with those in 1916 and 1917. 



Elm does not appear after 1917. There has been no seed crop in 

 the vicinity of Mandan from which to raise stock since that time. 



GROWTH STUDY OF COOPERATIVE SHELTER BELTS PLANTED 



IN 1916. 



During the summer of 1920 a special study was made of the shelter 

 belts that were planted in 1916. Of 633 originally planted, as given 

 in Table 8, 373 remained active at the beginning of the 1920 season. 

 Of this number 349, or 94 per cent, form the basis for the data given 

 in Tables 9 and 10. 



Table 9 shows for each State the percentage of the shelter belts 

 planted in 1916 in which the different species were living in 1920. 

 In the 349 shelter belts studied, box elder, green ash, and caragana 

 were living in every active planting, but willow and poplar survived 

 in only one-half to three-fourths of the plantings active at that time. 

 Both box elder and willow showed a better survival in South Da,kota 

 than in North Dakota, Montana, or Wyoming. This is probably due 

 to the somewhat more favorable conditions of moisture and tempera- 

 ture that exist in South Dakota. 



Table 10. 



Average and maximum height^ in the summer of 1920 of the dif- 

 ferent species of trees in shelter belts planted in 1916. 



state. 



Laurel- 

 leaf 

 willow. 



Russian 

 golden 

 willow. 



Norway 



or 

 Carolina 

 poplar.2 



Box 

 elder. 



Green 

 ash. 



Caragana. 



Montana: 



Average height feet 



Maximum height do 



North Dakota: 



Average height do 



Maximum height do 



South Dakota: 



Average height do 



Maximum height do 



Wyoming: 



Average height do 



3.75 

 7.00 



4.00 

 6.00 



5.50 

 9.00 



5.75 

 9.00 



4.25 

 7.50 



4.75 

 7.00 



6.00 

 7.00 



3.25 

 4.00 



6.50 

 18.00 



7.50 

 15.00 



12.00 

 18.00 



8.50 

 10.00 



5.75 

 10.00 



6.50 

 10.00 



7.50 

 11.00 



7.00 

 10.00 



4.00 

 7.00 



4.00 

 5.50 



3.50 

 4.00 



4.00 

 6.00 



4.00 

 5.50 



5.00 

 7.00 



3.00 



Maximum height do 





5.00 









1 Two measurements were taken in each shelter belt for each species, one at "a point judged to he the 

 average height of the row and one where the trees were tallest. The maximum height given is the highest 

 measurement found in any planting in the State. 



2 The Norway poplar and Carolina poplar were so similar in appearance that no attempt was made to. 

 distinguish between them. 



In each of the 349 shelter belts studied, measurements were made 

 of the average and maximum height of each species. A summary of 



