Practical Sylviculture 131 



formed trees and should be removed as soon as the stand 

 becomes too dense, yielding considerable fuel. This 

 mixture is suitable to soil slightly better than No. I. 



III. Burr oak and hackberry 4X4 feet. These species 

 are very hardy, but of slow growth. Close planting is ad- 

 vised, to shade the ground as soon as possible. When 

 crowding begins, thinning should commence with the hack- 

 berry, leaving the oak for the final crop. This mixture is 

 suitable for very poor, comparatively dry soil. 



IV. White elm and black locust 6X6 feet. The 

 locust grows more rapidly than the elm and can be ex- 

 pected to furnish posts and fuel in a comparatively short 

 time. The elm will shade the ground, keep out grasses 

 and maintain fairly good conditions. Thinning may be 

 made in both the elm and the locust. 



V. Boxelder and cottonwood in equal mixture 4X4 

 feet. The boxelder is slower in growth than the cotton- 

 wood and forms an understory and shade for the ground. 

 The cottonwood grows rapidly in height and produces 

 timber. Thinning should be made in the boxelder until 

 it is all removed, since in itself it is of little value, but is 

 used merely to aid the cottonwood. This mixture is 

 adapted to general prairie planting where soil moisture 

 may be reached readily by the roots. The trees in this 

 mixture are very hardy and can be counted on to endure 

 the severe colds in the northern prairies. 



The following mixtures are suitable for general planting 

 in the Lake States, or anywhere in the general range 

 of the white pine. 



I. Norway pine and jack pine in equal mixture 4X4 



