10 BULLETIN 316, U. S. DEPARTMENT OF AGRICULTURE. 
On the lower ground, such as small islands, old river beds, sand 
bars, and fills, the principal species present are black, sandbar, and 
peachleaf willows, and cottonwood above Cairo, 111., the peachleaf 
dropping out below that point. Above Cairo the peachleaf willow 
divides with the black willow the position of the leading tree willow, 
but does not quite attain the size of the black willow or grow so 
rapidly. The black willow is prevalent along practically the whole 
course of the Mississippi, increasing in abundance and size along the 
lower reaches. The black willow and cottonwood are as a rule the 
first tree species to appear on new land. 
FORM AND GROWTH OF INDIVIDUAL TREES. 
Black willow trees may be divided into two general classes — that 
found in the North or on poor soil in the South and that of the rich 
alluvial river bottoms of the South. The first are typically 30 to 60 
feet high and from 6 to 18 inches in diameter. They occur in pure 
stands over small areas or, more often, in groups of several clustered 
stems. In the open the black willow is a short, branchy, crooked 
tree, fit only for fuel. In close stands it has a moderately straight 
trunk or often two or three straight branches arising near the ground. 
The northern form, grown in close stands, can be utilized for fuel, 
charcoal, excelsior, or pulp, and occasionally for artificial limbs, but 
seldom develops into a desirable sawlog. The southern type is con- 
siderably different in habit of growth in the forest. The trunks are 
usually separate and stand quite erect. In the open the tree branches, 
like the northern form, being different only in its larger size. The 
forest-grown tree has a minimum clear length of 20 feet and an 
average clear length of about 40 feet, and, as a maximum, several 
specimens have been measured having over 80 feet of clear, straight 
bole. The tops of these trees are small, irregular, and often broken. 
The crowns are narrow, open, and deep. The average diameter in 
mature stands is about 18 inches at the mouth of the Ohio and in- 
creases to 24 inches in Mississippi and Louisiana. The largest breast- 
high diameter measurement recorded for a forest-grown black willow 
is 44 inches and the greatest height 140 feet. The tree with the 
greatest height measurement, however, was not the one with the 
greatest diameter growth. The 44-inch tree was not over 125 feet 
high and the 140-foot tree was not over 3 feet in diameter. The 
average height in mature stands at the mouth of the Ohio is approxi- 
mately 85 feet; in Louisiana it ranges from 100 to 120 feet. Black 
willow is a short-lived tree. The greatest age recorded for a sound 
tree is 70 years; the greatest age recorded for a living but unsound 
tree is 85 years. The average age at which stands mature is 55 years 
and under favorable conditions may be 10 years less. 
