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 



Figure 4. A good tree claim. Planted by Mr. Gardner, of Lyons 

 county. Located on high prairie. Soil very dry. Has planted about 30 

 acres in trees. 



or Boxelder. (4) Mixed plantings 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 ^ha<ie the ground when the 

 others are gone. On the outside, especially on the north and 

 it is "I'ten a giHMJ plan In put at least .- few rows of White 



