98 Horticultural Department. [Bulletin 120 



A good average tree, growing in fairly rich soil, at twenty-four 

 years gave the following measurements : 



Height 71 feet. 



Diameter at base 28 inches. 



" at 5 feet 24 " 



" at 10 feet 21 " 



" at 20 feet 19 " 



" at 30 feet 12 " 



making one good and one fair log for sawing, and the tops and branches 

 containing slightly over one-half cord of wood. 



Measurements made of a small grove in Rice county, growing in 

 sandy land of fair quality, averaged at nineteen years : Diameter at 

 five feet from the ground, 16 inches ; at ten feet, 13J inches ; at fifteen, 

 10J inches. 



As a shade or street tree, the desirability of the cotton wood is 

 questionable. The cottony substance which floats the seeds is ob- 

 jectionable when the seeds are ripening, but this may be avoided by 

 planting trees propagated from cuttings of staminate-flowered trees. 

 Cottonwoods are propagated from seed, which should be sown as soon 

 as ripe, covering it lightly. The young seedlings are easily obtained 

 from sand-bars in the principal rivers, and frequently from fields near 

 seed-bearing trees. Cuttings of ripe wood are easily grown. 



WHITE OR SILVER POPLAR. (Populus alla.) i 



White or Silver poplar is much the same in characters of growth 

 as the cottonwood, the timber being more valuable. It has been 

 much shorter- lived and not so resistant in regard to drought and cold, 

 much more liable to sprout badly, and much less certain to form 

 straight trunks than the cottonwood. It is readily propagated from 

 cuttings and suckers. 



LOMBARDY POPLAR. (Populus nigra italica.) 



This species has proved to be short-lived in all situations. For the 

 first few years a rapid growth was made, but later growths have been 

 uneven and irregular, with many dead branches. It has little to recom- 

 mend it. 



QUAKING- ASP. (Populus tremuloides.) 



The only planting of this species was made in a block set by the 

 United States Division of Forestry in 1897. The trees have made a 

 rapid growth, but are less vigorous and probably less hardy, and. as far 

 as noted, inferior to the Cottonwood. 



