COTTONWOOD IN THE MISSISSIPPI VALLEY. ~ 25 
trees are about 12 years old and because the number of board feet 
to each ‘cubic foot increases as the 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 3 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 vears. 
TABLE 4.—Yield of pulpwood per acre in the lower Aflississippi Valley. 
| (| 
| 
| Average | Average | 
Age. | . Total yield. annual || Age. | Total yield. annual 
yield. | yield. 
Years. | Cubic jeet.| C nds. Cords. | Years. | Cubic feet. | | Cords. Corés. 
5 630 6 re ets |e 4, 460 7 3.6 
6, 810 5.3 Det a i AON | pO 3.5 
7 1,020 10.7 5 | 15 4,830 | 50.8 3.4 
8 1,320 13.9 Si, 16 eA IG r ee Sie ae, 
9 x Ie" 18.0 2.0 | 17 | 4960 |= 52.2 = Jk 
10 2,330 24.5 255 18 4,990 GA DEG 
11 3,400) | 3256 3.0 19 | 5,010 52:7 2:8 
12 4,050 | 42.6 = ei) 20 55,020.) 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 
unpeeled 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 ae 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 Iowa 
and Minnesota would seem to indicate, as might naturally be ex- 
pected, that the yield i 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. 
347 = Bull. 24-13 ——4 
