SIZE OF EFFICIENT WlKD&^fiA^f 99 



middle of the space in the other. White .cMr #<& yer^drBciem low 

 windbreak, and is also very inoffensive in relation to crops, both as 

 regards shading and sapping. 



(b) On very poor, sandy soils, red and Scotch pines may be used in 

 belts of the character described for Class B situations on the northern 

 prairies. The spruces may be supplanted by jack pine as an auxiliary, 

 but this species should be used sparingly, as it is extremely aggressive 

 in competition with other forest trees on raw soils. 



4. THE EASTERN STATES. 



In the northern portion of this region, where the winter winds 

 chiefly are to be feared, white pine may be as fully recommended as 

 in the Lake States. The native white spruce, Norway spruce, or 

 white cedar may be used with equal advantage as an auxiliary, but, 

 in small quantities. The last will probably find the most ready market, 

 since the spruces will be valuable only for pulpwood. A double row 

 of Norway spruce forms an excellent windbreak when timber values 

 are not to be considered. The ideal spacing seems to be about 8 by 8 

 feet. The north-south windbreak will here act as a barrier to nearly 

 every wind, since all are of westerly origin. 



Toward the south in this region, where, because of the greater 

 summer heat the conservation of moisture becomes more important, 

 chestnut and tulip poplar may be recommended as the most profitable 

 hardwoods, and may be used even on rather barren or worn-out soils. 

 Both grow thriftily and may be managed as coppice. As an auxiliary, 

 short-leaf pine may be suggested for use on soils too poor for white 

 spruce or white cedar. The common red cedar, which is such an im- 

 portant feature of natural hedgerows, should not be allowed to exist 

 in the neighborhood of apple or pear orchards. 



5. THE SOUTHWEST. 



Very little windbreak planting has been done in the poorly watered 

 region of the southwestern United States, although it is evident that 

 here, of all places, protection from wind and conservation of moisture 

 are most needed. 



Artemisia or sagebrush has been used to some extent in New Mexico. 

 Because of the low height attained by these shrubby species, the 

 hedges must be very close. With a height of 4 feet, hedges should 

 be placed at intervals of from 80 to 100 feet. The east-west orien- 

 tation will best obstruct the continental winds blowing ofT the Gulf 

 and the anticyclonic winds, usually from a southwesterly source. 



Although osage orange is native only to the river bottoms of this 

 region, it is believed that with the encouragement of cultivation this 

 species could be made to grow in much of the territory wheiv dry 

 farming is practiced. 



