26 BULLETIN 299, U. S. DEPARTMENT OF AGEICULTUEE. 



the open, diameter growth is more rapid, but the tree develops only 

 a very short trunk and large, wide-spreading lateral branches, and is 

 very much inclined to fork, all at the expense of growth in height, and 

 of length, clearness, and cylindricity of bole. Unfavorable sites 

 make themselves at once apparent in a lower rate of height growth 

 in dominant trees. The boles are shorter, more apt to be crooked, 

 and more branchy. In mixed natural stands on such sites ash is 

 usually a spindling, overtopped tree. 



In original forests, ashes from 200 to 300 years old, 3 to 5 feet in 

 diameter, and from 125 to 175 feet in height were formerly common, 

 but now 3 feet in diameter is exceedingly large. White ash attains 

 greater height than black or green ash, but is surpassed in diameter 

 and age by black ash. Green ash grows larger in diameter than white 

 ash, but does not become so tall nor live so long. 



Crowns of dominant ash trees growing in the forest occupy usually 

 one-third to half the total height of the tree, more on young trees and 

 less on old trees. During the period of rapid height growth, which 

 continues till the tree is from 40 to 60 years old, the crown is rather 

 narrow in proportion to its length and more or less cone shaped; as 

 its age increases it broadens out and becomes dome shaped, and in 

 old age comparatively flat. In youth the crown is considerably 

 longer than it is wide, but this changes with age until the width is 

 greater than the length. Trees crowded on the sides have short, 

 oppressed crowns, often occupying less than a quarter of the total 

 height. (PL VIII, fig. 2.) 



Ash, because of its intolerance, prunes itself readily when growing 

 in the forest, and develops long, clear, straight boles commonly free 

 of branches for half its total height. The boles have usually a com- 

 paratively rapid taper (Tables 25 to 29) . Ash trees which have grown 

 under very crowded conditions often have clear lengths of two-thirds 

 or more of their total height. 



The species vary somewhat in their characteristic forms as a 

 result of their relative tolerance. Blue (PL IX, fig. 1), black, and 

 water ashes have the most persistent limbs and the shortest clear 

 lengths, develop "water sprouts" under lesser light conditions, and 

 for this reason are less desirable to grow (on good sites at least) than 

 white, Biltmore, green, and red ashes. 



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