ESTIMATES AND DISCUSSION. 



81 



desirable. (3) The best posts are obtained with the closest spacing 

 in groves. Without close spacing the trees are crooked, branchy, and 

 knotty. (4) Dry situations greatly retard the growth of ash, and 

 since its rotation is long on the best situations, it should not be 

 planted on the poorer ones unless needed for protection. 



SILVER MAPLE. 



The silver or soft maple is a native of the river banks and well- 

 watered lands of the Middle West. It is a moderately rapid grower, 

 but its wood is not durable, and for posts is no more valuable than 

 cottonwood and willow^. The timber is principally useful for fuel. 



Soft maple is a fairly vigorous rooter and succeeds on moderately 

 dry uplands. The tree supports a rather large and dense crown, 

 which makes it especially valuable for protective purposes. The 

 lower branches persist, with their foliage, as long as they can obtain 

 any light, so that even a single row of soft maple makes a fairly dense 

 windbreak. The tree has been chiefly planted in belts and groves. 

 The area charged to maple on the edges of belts and groves is calcu- 

 lated on the basis of the damage to corn. This was found to be 61.43 

 per cent for the north side and 62.90 per cent for the south side. 



The estimates of silver maple given in Table 19 include the entire 

 volume usable for fuel. 



TABLE 19. Silver maple estimates cordwood. 



WILLOW. 



Willow is not a valuable tree, but on good, moist soil it grows very 

 rapidly at the start, and in a few years will furnish an immense amount 

 of material, of which most has some usefulness in the form of posts and 

 all may be used for fuel. Willow posts of the commonly planted 

 species are not durable, but are somewhat more valuable than cotton- 

 wood posts. "Diamond willow" (Salix cordata madcenziana Hook), 

 on the other hand, a native along the banks of some of the streams in 

 Nebraska, is very durable, and surpasses almost any of the native 

 species for posts and fuel. The willow commonly planted in northern 

 92290 Bull. 8611 6 



