WILLOWS: THEIR GROWTH, USE, AND IMPORTANCE. 39 
Another method which has been used to good advantage at the 
bends of small streams is to drive willow stakes 2 to 4 inches in diameter 
into the bank upward from the water's edge at low water and quite 
close together and to fill the spaces between them with loppings 
from willow trees or brush of all sizes, of which as much as possible 
is made to touch the ground or is partially buried. Additional forked 
stakes are useful in making the brush secure. This procedure insures 
a growth of willows that will protect the bank from further erosion. 
In all operations for bank protection it is important to remember: 
(1) That a perpendicular caving bank must be made sloping before 
planting can be effective; (2) that planting should begin at the water 
line and proceed away from the stream; (3) that mechanical aids are 
often necessary to create conditions where planting can be done 
effectively; (4) that any part of a live willow and (usually) a cotton- 
wood will grow vigorously if placed in moist soil. 
BANK REVETMENT. 
Willow is largely used in the making of mattresses for bank revet- 
ments along the lower Mississippi River and its tributaries. In one 
district alone, in 1913, 145,847 cords were used. The total amount of 
willow used for this purpose is from 300,000 to 400,000 cords per year. 
The trees are largely sandbar, peachleaf, or black willow, and are 
small, ranging from 1 to 5 inches in diameter and from 25 to 40 feet 
in length. In the New Orleans district cull lumber is used for the 
mats. This is partly because willows are not quite so plentiful in the 
lower portion of the valley and partly because the different districts 
working separately developed somewhat different methods of dealing 
with bank protection. Of the three species most commonly used 
the sandbar willow is the best. It is of slower growth than the other 
species, but it comes up in very dense stands and grows very straight. 
In thick stands it is practically free from branches except for a small 
crown. The habit this species has of sprouting prolifically from the 
roots insures a heavy stand when once started. The wood is slightly 
heavier than the other willows and somewhat tougher and stronger. 
Practically speaking, there is little difference in species, and con- 
tractors pay less attention to species than to size and form. 
The plentiful supply of willows has heretofore made their cost 
simply that of cutting and transporting them. In the last few years, 
however, the willows in the immediate vicinity of some of the larger 
revetment works have become so scarce that from $1 to $2 per acre 
has been paid for the privilege of cutting over private lands. The 
best willows come from the lower sand bars and islands. Willows 
growing above the 35-foot stage of the river are seldom used, both on 
account of the expense of getting them to the water and the fact that 
they are seldom of the right quality, being generally crooked and 
