52 ELEMENTARY FORESTRY. 
is generally true of Hard Maple in this section and of Catalpa 
and Black Walnut in Southern Minnesota. (3) In good mixed 
plantings the ground is more likely to be properly shaded and 
protected from winds than it would be in clear plantings of such 
thinly-leafed species as the Cottonwood or White Elm, which 
do well and afford good shade when mixed with Green Ash 
bs 
Figure 4. \ good tree claim. Planted by Mr. Gardner, of Lyons 
county. Located on high prairie. Soil very dry. Ilas planted about 30 
acres in trees. 
or Boxelder. (4) Mixed piantings are most interesting and 
ornamental. (5) They attract more birds by their better pro- 
tection and the greater variety of food offered. (6) While the 
chance of injury to some of the species by climatic changes, dis- 
eases and insects is increased, the possibility of total loss from 
any or all of these causes is reduced to the minimum. 
The Most Important Constituent of a Prairie Grove 
of mixed trees in this section should be some well-known dura- 
ble kind, as the Elm, Ash or Boxelder, of which there should 
be a sufficient number to completely shade the ground when the 
others are gone. On the outside, especially on the north and 
west, it is often a good plan to put at least » few rows of White 
