AMERICAN FOREST TREES 669 



There is no danger that cottonwood will disappear from this 

 country, but it will become scarce. It is being cut much faster than it is 

 growing, and is losing favor as a planted shade and park tree, because of 

 its habit of shedding cotton in the spring and its leaves in the early 

 autumn. 



SWAMP COTTONWOOD (Populus heterophytta) is known also as river 

 cottonwood, black cottonwood, downy poplar, and swamp poplar. Its 

 range describes a crude horseshoe, running from Rhode Island down the 

 Atlantic coast in a narrow strip, where it is neither abundant nor of large 

 size ; touching northern Florida ; running westward to eastern Texas and 

 thence up the Mississippi basin and the Ohio river to southwestern Ohio. 

 There is nothing handsome about its appearance with its heavy limbs 

 and sparse, rounded crown. In the eastern range the average height is 

 probably not more than fifty feet but in the fertile Mississippi valley it 

 reaches 100 and has a long merchantable bole three feet in diameter. 

 Its bark is rugged, dirty -brown and broken into loose, conspicuous 

 ridges. It is easily distinguished from the other cottonwoods by the 

 orange-colored pith in the twigs. The buds are rounded and red and 

 have a resinous odor. Sawmills and factories never list this wood 

 separately. It comes and goes as cottonwood. Its uses are the same 

 as those of common cottonwood. The two species grow in mixture 

 throughout the entire range of the swamp cottonwood. 



TEXAS COTTONWOOD (Popultis wislizeni) is a rather large tree and 

 is the common cottonwood in the upper valley of the Rio Grande in New 

 Mexico and western Texas. The yellowish color of the twigs 

 is apt to attract attention. The wood is used about ranches and oc- 

 casionally a log finds its way to local sawmills; but its importance is 

 limited to the region where it grows. 



MEXICAN COTTONWOOD (Populus mexicana) extends its range 

 north of the Mexican boundary into southern Arizona and southwestern 

 New Mexico. It is abundant in Mexico where the largest trees are 

 eighty feet high and three or four in diameter. It is smaller near the 

 northern limits of its range, and there it hugs the banks of mountain 

 streams. Stockmen use the trunks, which are usually small enough to 

 be called poles, to make fences and sheds. 



NARROWLEAF COTTONWOOD (Populus angustifolia) is a mountain 

 species which manages to live in the semi-arid regions from the Rocky 

 Mountains of Canada to Arizona, but is seldom found below an elevation 

 of 5,000 feet, and it ranges up to 10,000. Trunks are eighteen inches 

 or less in diameter, and fifty or sixty feet high. The seeds are larger 

 than those of most other cottonwoods. It being a semi-desert species, 

 its wood is appreciated where it is accessible, and it has local uses only. 



