COTTONWOOD IN THE MISSISSIPPI VALLEY. 27 
hight must in particuiar be fully met. In logging mixed stands the 
trees which are of little value to the lumbermen, and are therefore 
commonly left standing after the removal of the cottonwood and 
many other merchantable species such as ash, red gum, or oak, should 
also be taken out. The shade cast by these weed trees and by under- 
brush tends to prevent the reseeding of the area to the light-demand- 
ing cottonwood. Rarely does one find good restocking of this species 
except on wide clean openings, such as are sometimes made by hurri- 
canes or by laying out logging roads, drainage ditches, and the like. 
Even in pure cottonwood stands it is unusual to find satisfactory 
restocking after logging, under present methods. Pure stands after 
40 or 50 years’ growth thin out and expose the forest floor to sunlight, 
thereby inducing the entrance of undergrowth, such as poison ivy, 
pepper vine (“cow itch”), briers, dogwood, and privet, and occa- 
sional seedlings of the more tolerant species. After logging opera- 
tions such growth is left in control of the area, and usually prevents 
the reproduction of cottonwood. Moreover, pure stands on the more 
recently made land along the river are sometimes culled over for the 
largest timber befere all the trees are merchantable. This serves 
further to open up the stand. It is customary to cull pure stands on 
islands and bars along the river several times, at intervals of 5 to 
10 years. Under such conditions there is little chance of securing 
cottonwood reproduction after the final cut, unless all undergrowth 
is removed and cottonwood is planted. 
The opportunity for managing cottonwood conservatively in the 
Mississippi bottoms is in some respects unparalleled. Nowhere else in 
the United States are there large areas of overflow bottomland unfit 
for agriculture which can be bought for from $3 to $5 an acre. Taxes 
on the land form scarcely any burden. In parts of the valley all un- 
improved land outside the levees is assessed at a uniform value of $1 
per acre. In the South the assessed value rarely exceeds $2 or $3, 
with a tax rate of about 20 mills. Fire hazard is usually negligible, 
due to the annual spring floods, which carry away a large proportion 
of the inflammable material. It is true that much of this material is 
again deposited along the river banks, but, as a rule, on such situa- 
tions growing cottonwood on a commercial scale is out of the ques- 
tion. Whatever débris remains in the cottonwood stands after a 
flood, being water soaked, decays rapidly. Furthermore, even when 
fire is a menace, cottonwood at the age of 15 or 20 years has formed 
comparatively fire-resistant bark from one-third to two-thirds of an - 
inch thick. 
Neither insects nor fungi seem to be a serious menace to cottonwood 
in the Mississippi Valley. This comparative freedom from disease 
is probably due largely to the favorable conditions for forest growth 
characteristic of rich, alluvial lands. Trees which are making vigor- 
