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 Dakota 
than in Xorth 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 1 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 
Maximum 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 
5.00 
1 Two measurements were taken in each shelter belt for each species, one at a point judged to be 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 
