TREES AND SHRUBS FOR THE NORTHERN PLAINS 25 



Acer mandshuricum. — This species was tested at the Mandan 

 station only. Loss was suffered after the 1936 drought. Growth 

 habits of this species would class it as a tall shrub. Data indicate 

 that it has promise for dry-land windbreak or ornamental planting. 



Acer negundo. — This species was widely tested over the northern 

 Great Plains. It was highly subject to winter injury, the extent of 

 which varied from year to year, depending on moisture conditions. 

 The trees in most dry-land plantings were killed to the ground by 

 such injury following the droughts of 1934 and 1936. This species 

 makes a rapid recovery when moisture conditions are favorable 

 (fig. 1). The trees have a wide-spreading habit of growth, which 



Figure 1. — These 23-year-old trees of Acer negundo growing under dry-land con- 

 ditions made an excellent recovery in 1938 following their killing to the ground 

 in the fall of 1934. Annual precipitation was approximately normal or above 

 in 1935, 1937, and 1938. The most severe drought of the 1914-50 period 

 occurred in 1936. 



may cause suppression of species in adjacent rows. Trees of A. 

 negundo are useful for windbreaks on sites that have favorable 

 moisture conditions. 



Acer saccharinum. — This species has been planted to some extent 

 for both dry-land windbreak and ornamental purposes in the area. 

 The trees suffered winter injury in most years. Such injury was 

 severe in the winter following the drought of 1934. The species 

 did quite well as an ornamental under irrigation. It is highly rec- 

 ommended for both windbreak and ornamental plantings under 

 irrigation . 



Acer tataricum. — This species has been planted to a very limited 

 extent in the area. It closely resembles A. ginnala in growth habits 

 and in the fall coloring of foliage. Losses were heavy in the late 



