28 
closely and introduces the chemicals. By the time the last tent has 
been adjusted the first one can be removed and taken across to the 
adjoining row. An experienced crew, with one director, can treat 
350 to 400 five-year-old trees, averaging in height 10 feet, in a single 
night of eleven or twelve hours. The cost under such conditions aver- 
ages about 8 cents a tree. 
With large trees the large sheet tents are drawn over them by means 
of uprights and pulley blocks. Two of these sheets are necessary for 
very large trees, the first 
being drawn halfway over 
and the second drawn up and 
made to overlap the first. In 
the case of trees from 24 to 
30 years old and averaging 30 
feet in height, about 50 can 
be treated in a night of ten or 
twelve hours with an equip- 
ment of 12 or 15 tents, the 
cost being about 75 cents per 
tree. It is not practicable to 
treat trees above 30 feet in 
height. 
The handling of the bell 
tents is simple and needs no 
further description, but the 
large tents are not so easily 
operated, and the method of 
adjusting the great flat octag- 
onal sheets over the trees, 
while simple enough when 
once understood, warrants a 
description. The machinery 
employed consists of two sim- 
ple uprights, with attached 
blocks and tackle (fig. 4). 
Willie The uprights are about 25 feet 
ourtet a 7 high, of strong Oregon pine, 
2 by 4 inches, and are pro- 
vided at the bottom with a 
braced crossbar to give them strength and to prevent their falling to 
either side while the tent is being raised. A guy rope is attached to the 
top of each pole and held to steady it by two of the crew stationed at 
the rear of the tree. The tent is hoisted by means of two ropes 70 feet 
long, which pass through blocks, one fixed at the top of the pole and 
the other free. The tent is caught near the edge by taking a hitch 



Fie. 4.—Method of hoisting sheet tent (after Craw). 



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