or single rows, however, on account of their extensive root system, can 

 maintain themselves in drier situations. So many failures have re- 

 sulted from attempts to establish cottonwood groves on upland soils 

 that it is usually considered impossible to grow the tree except in 

 rows along highways and similar places. So planted, the trees are 

 valuable for windbreaks and give good returns in fuel and repair 

 material. However, more satisfactory results will be secured by 

 planting in permanently moist situations if production of lumber is 

 desired. 



Abundant light is required for development, and young stands tend 

 to become thin. The crown cover is frequently so sparse that grass 

 and shrubs come in under the trees and check growth. This draw- 

 back can be prevented by underplanting the grove with shade-endur- 

 ing trees. 



Growth in early life is very rapid. Small trees in a single year 

 may increase from 3 to 5 feet in height and from 1 to 3 inches in diam- 

 eter. Between the ages of 10 and 15 years the rate of growth gradu- 

 ally lessens, and under certain conditions maturity is soon reached. 



Cottonwood is comparatively free from insect pests, though leaf 

 insects occasionally do serious damage. In case of severe attacks ap- 

 plication should be made to the Bureau of Entomology of the Depart- 

 ment of Agriculture for information in regard to methods of control. 



ECONOMIC USES. 



The wood of cottonwood is light and soft. It is not strong, and it 

 decays rapidly in contact with the soil. Regional factors of climate 

 and soil cause marked differences in quality. In western Kentucky 

 and Tennessee, for instance, the so-called yellow cottonwood fur- 

 nishes a much better grade of wood than in the Missouri River region. 

 The wood has a tendency to warp in seasoning, but this may be over- 

 come by proper methods of piling. 



Paper pulp, box boards, backing for veneer, the unexposed parts of 

 furniture, wagon boxes, interior woodwork and boarding, and fuel 

 are the principal products for which the wood is used. The increased 

 value which the tree is gaining for these uses, coupled with the ease 

 and rapidity with which it can be grown, renders it one of the im- 

 portant species for commercial planting in the Middle West. Its 

 fuel value in some regions is especially high, since it furnishes a 

 greater amount of wood in a given time than other species. In pro- 

 portion to volume the relative heat production is, hoAvever, low. 



Cottonwood is useful for protecting agricultural lands subject to 

 annual overflow. A narrow belt of trees on the river side of such 

 lands protects the fields from debris and checks the erosive action 

 of the water. Plantations of cottonwood established on land between 



[dr. 77] 



