COTTONWOOD IN THE MISSISSIPPI VALLEY. 61 
used, it should be planted with the cottonwood in the proportion of 
8 to 1, with a row of the fillers alternating with a row in which 
every other tree is a cottonwood. 
‘SPACING. 
Where pulpwood production on a short rotation is desired, an 
initial spacing of 8 by 8 feet will give the best results. This will 
serve tc clear the branches early and will allow one thinning where 
it may be financially justifiable. 
For timber a spacing of 10 by 10 feet cn the richest bottom lands 
is not too wide for the best growth of cottonwood. Thinning opera- 
tions with such spacing could be deferred for a long time, as they 
would be of little advantage before the age of 12 to 15 years. 
The readiness with which cottonwood thins itself naturally makes 
wider spacing than this inadvisable, and on average soils a spacing 
of 9 by 9 feet may be best. On comparatively dry soils a spacing 
as close even as 6 by 6 or 7 by 7 feet may sometimes be justified. 
A general spacing of 6 by 6 feet, in which the cottonwood is set 
12 feet apart each way and the intermediate spots are planted with 
a filler, is probably the best for mixed plantations. In such spacing 
every other row would contain only ‘trees of the species used as a 
filler, while the intermediate rows would consist of cottonwood alter- 
nating with the filler. This would give a stand of about 300 cotton- 
woods to the acre, which is a normally dense stand between the ages 
of 14 and 15 years. Therefore, no thinnings would be needed before 
the plantation had become from 15 to 20 years old, when much of 
the material removed would probably be marketable for pulpwood, 
excelsior, etc. If the original planting were 8 by 8 feet, with the 
cottonwoods 16 by 16, the stand would not become much overcrowded 
during a rotation of 25 years. In the latter case, however, less pro- 
vision would be made for trees injured or killed, and the timber 
would probably be less perfectly cleared of its side branches 
SUMMARY. 
Cottonwood is perhaps the most important tree in the Mississippi 
Valley, and may be expected to play a large part in the future pro- 
duction of lumber, veneer, and pulp wood. It grows rapidly, and can 
be cut for pulp wood when 15 years old and for timber and veneer in 
35 years. To the owner of unprotected bottom land, lumber and pulp 
companies, therefore, it should appeal as a profitable tree to grow in 
the region, especially on the extensive areas outside the river levees. 
Cottonwood does not renew itself on cut-over land unless special 
care is taken in logging. A direct effort must be made therefore to 
secure restocking on the ground after cutting, either naturally or by 
