﻿48 BULLETIN 24, U. S. DEPARTMENT OF AGRICULTURE. 



PLANTING. 



ADVISABILITY. 



"Wherever fully stocked stands can be secured by natural reproduc- 

 tion no planting need be done. Where seed trees of cottonwood are 

 wanting, on low-lying areas where water stands late in the spring, 

 and on areas where young seedlings might be choked but" by vines, 

 briers, or low underbrush, it will be necessary to supplement natural 

 reproduction with planting. "Without planting, many portions of 

 the logged-otT areas would be only indifferently restocked, while in 

 some places reproduction would be entirely lacking. 



.Planting, however, is not limited to the restocking of cut-over 

 bottom lands. A tree of such rapid growth and value as cottonwood 

 will no doubt be introduced into localities where it is not now found 

 naturally. The present local occurrence of cottonwood does not 

 necessarily coincide with the areas where it might be expected to 

 make good growth. The fact that this species is seldom found grow- 

 ing naturally far from streams or moist bottom lands is the result of 

 the failure of its seed to germinate satisfactorily on any but moist 

 exposed mineral soils, such as are provided by the deposits from 

 spring floods. This difficulty, however, is avoided by planting young 

 trees. "When the roots of the planted stock penetrate to a moist 

 subsoil the tree displays its usual rapid development. 



Carolina poplar and Norway poplar are extensively advertised 

 by nurserjmien as superior to the common cottonwood for rapid 

 growth in forest plantations. The three trees are all closely related. 

 Differences in leaf and growth characteristics are often urged as 

 grounds for considering Carolina poplar and cottonwood as 'distinct 

 species. Carolina poplar itself, however, shows widely varying 

 characteristics in different sections of the country, a id often can not 

 be distinguished from cottonwood. The differences between Norway 

 poplar and cottonwood are equally vague. Both Norway and Caro- 

 lina poplar are male trees propagated entirely from cuttings, and it 

 is believed that both are derived from staminate trees of our com- 

 mon cottonwood. It has already been pointed out that cottonwood 

 has been commonly planted in Europe, where certain nurserymen 

 claim to have developed exceptionally rapid growers. Possibly our 

 Norway poplar may have originated in some such way, or it may 

 have been taken originally from some of these rapid-growing Euro- 

 pean forms. It is not at all certain, however, whether it really ex- 

 ceeds our native cottonwood or the Carolina poplar in growth. Indi- 

 cations are that in the north cuttings from thrifty Carolina or Nor- 

 way poplar may develop more rapidly than cottonwood. In fact, 

 it is generally believed that the male trees are more vigorous growers 

 than the female. Another merit claimed for Norway poplar in com- 



