EASTERN NEW MEXICO AND WESTERN TEXAS. 39 



REQUIBED NUMBER OF TREES PER ACRE. 



Black locust 680 



Russian mulberry 680 



Total 1, 360 



In addition to the windbreaks about the farmstead, trees should be 

 planted in strips at least 2 rods wide running east and west across the. 

 farm, and separated by open fields not more than 80 rods wide. 

 These will serve to protect the crops against hot winds. These wind- 

 break belts should be laid out as follows: 



The trees should be planted 4 feet apart in rows 8 feet apart. The 

 first or inner row on the windward side of each field should be of 

 honey locust, black locust, or cottonwood. according- to the nature of 

 the soil. Cottonwood should be used only on subirrigated land. 

 Black locust will do best on moderately good soil and honey locust 

 in the driest situations. All of these trees are rapid growers, and 

 will soon give some shelter to the field. The main body of each wind- 

 break should be planted with some of the following slower-growing, 

 longer-lived species : 



Green ash. Hackberry. 



Coffeetree. Wild china. 



White elm. Black walnut. 



Diagram 13 shows the arrangement of one of these windbreaks. 



Diagram 13. — Mixture for a windbreak on semiarid plains., 

 (Spacing U by S'.) 



Y H Y H 

 A E A E 



Y H Y H 

 A E A E 

 X X X X 



FIELD. 



X=Cottonwood. honey locust, or black locust. E=White elm. H=Hack- 

 berry. A = Green ash. Y=Wild china, coffeetree, or black walnut. 



REQUIRED NUMBER OF TREES PER ACRE. 



Single row of pure cottonwood. honey locust, or black locust- 1, 360 



Mixture of — 



White elm 340 



Hackberry 340 



Green ash 340 



Wild china 340 



Total 1,360 



