﻿COTTONWOOD IN THE MISSISSIPPI VALLEY. 15 



from this source are especially pronounced in the Red River Valley 

 region of Texas and Oklahoma. Although the apparent injury is 

 confined to the branches, the vitality of the whole tree is weakened 

 through loss of nourishment withdrawn by the parasite. 



Many species of insects attack cottonwood, but with few exceptions 

 cause no serious damage to the trees. The exceptions are found in 

 one or two species, the larva? of which bore into the living bark and 

 sapwood, sometimes doing serious damage. If any serious injur}' 

 by insects is found, the matter should be reported to the Bureau of 

 Entomology, Department of Agriculture, Washington, D. C. Speci- 

 mens of the insects or of their work should accompany such a report. 



The thin bark of young cottonwoods is relished by field mice and 

 rabbits, and at times large numbers of trees are completely girdled 

 by their gnawing. Girdling by mice is most likely to occur under 

 snow or in deep grass. Ro'dents may destroy most of the young 

 trees or cuttings in a cottonwood plantation, which makes planting 

 on grassy sites a hazardous undertaking. Seedlings^ however, usu- 

 ally sprout from the root collar below the injury. In the case of 

 natural reproduction, where the trees come up so densely that the 

 loss of 75 per cent or more during the first two or three years is 

 of little consequence, the damage from this source is but slight. 



Cattle are very fond of the green shoots and foliage of cottonwood 

 and should be kept out of young growth, either natural or planted, 

 for the first three or four years, after which they will do but little 

 harm. 



Cottonwood is very susceptible to fire injury while young, but by 

 the time it is 15 to 20 years old has produced a fairly fire-resistant 

 bark. Fires are, moreover, not likely to start or become serious on 

 bottoms subject to overflow. Young cottonwood stands should be 

 carefully protected against fire. 



REPRODUCTION. 



FROM SEED. 



Cottonwood reproduces readily both by seed and by sprouts. 

 Female trees bear seed in abundance practically every year. They 

 begin to seed very early in life, probably when not over 10 years of 



