118 



ELEMENTARY FORESTRY. 



the proper time so as not to get the soil filled with roots will 

 also help to prevent injury from drouth. Willow windbreaks 

 can be grown without any cultivation after being- once well 

 established in the driest portion of Minnesota if they are kept 

 mulched with straw or litter for six feet on each side. Mulch- 

 ing also prevents injury from severe freezing of the roots. 



Sun-scald. Nearly all of our cultivated trees may be in- 

 jured by sun-scald. This occurs almost without exception on 



Fip. 3O. Trunk of 

 Soft Maple badly sun- 

 scalded. 



Fis. 31. SECTION OF TRUNK 

 OF SUN-SCALDED BASSWOOD. 

 Showingdead harkand amount 

 of wood decayed. The top and 

 roots of the tree from which 

 this section was cut were per- 

 fectly healthy at the time when 

 the trunk broke off at the sun- 

 scald. 



the southwest side of unprotected trees of Hard and Soft 

 Maple, Basswood, Box Elder, Black Walnut, etc. Oaks and 

 all other trees are occasionally affected. It never occurs 

 when the trees are sufficiently close together to shade their 

 trunks, and for this reason the growth of shrubs and low 

 branching trees should be encouraged on the south and west 

 sides of groves where they do not crowd the principal kinds. 



