﻿COTTONWOOD IN TffK MTSKISKiIM'T VALLEY. 



25 



trees are about L2 years old and because the number of board feet 

 to each cubic foot increases as (lie tree increases in size. In logs 

 of large diameters each cubic foot will saw out more than 7 or 8 

 board feet, whereas in small logs there may be only 2 or 8 board 

 feet. 



Table 4 gives the yield of pulpwood for stands from 5 to 20 years 

 old under the most favorable conditions of growth. Older stands are 

 not considered, because the maximum average annual yield in cords 

 per acre occurs at a considerably earlier age than 20 years. 



Table 4.— Yield of pulpwood per acre in the, lower Mississippi Valley. 







Average 







Average 



Age. 



Total yield. 



annual 

 yield. 



Age. 



Total yield. 



annual 

 yield. 



Yjars. 



Cubic feet. 



Cords. 



Cords. 



Years. 



Cubic feet. 



Cords. 



Cords. 



5 



630 



6.6 



1.3 



13 



4,460 



47.0 



3.6 



6 



810 



8.3 



1.4 



14 



4,690 



49.4 



3.5 



7 



1,020 



10.7 



1.5 



15 



4,830 



50.8 



3.4 



8 



1,320 



13.9 



1.7 



16 



4,910 



51.7 



3.2 



9 



1,700 



18.0 



2.0 



17 



4, 960 



52.2 



3.1 



10 



2,330 



24.5 



2.5 



18 



4,990 



52.5 



2.9 



11 



3,100 



32.6 



3.0 



19 



5,010 



52.7 



2.8 



12 



4,050 



42.6 



3.5 



20 



5,020 



52.8 



2.4 



The volumes of the trees were determined up to a top diameter of 

 4 inches inside the bark, except where the stem was too crooked or 

 branchy. The cubic-foot volume was converted into cords by divid- 

 ing it by 95, a liberal factor for converting solid cubic feet into 

 stacked measure. The cordwood figures are for peeled wood. Where 

 impeded wood is purchased with the intention of running it through 

 a barking machine at the mill these figures will be too low. The bark 

 constitutes about 22 per cent of the total volume. The figures in the 

 table therefore represent only 78 per cent of the total cubic contents. 

 The largest average annual yield is obtained at 13 years, at which 

 time there is a total stand of 47 cords. The growth and yield 

 tables are naturally restricted in their application to cottonwood 

 stands in the central and southern United States, where the measure- 

 ments were made, and particularly to overflow lands along the rivers 

 and streams. Observations on the growth of cottonwood in Iow T a 

 and Minnesota would seem to indicate, as might naturally be ex- 

 pected, that the yield in the northern part of the country would fall 

 considerably below that in the South. 



It was difficult to find pure cottonwood stands in Iowa and Minne- 

 sota in which normally stocked plots could be laid off. Only a half 

 dozen plots were measured, ranging from 25 to 55 years. The results 

 are given in Table 5. 



S471°— Bull. 24— 13 -4 



