50 
BULLETIN 544, U. S. DEPARTMENT OF AGRICULTURE. 
The use of strips up to 300 feet wide or more will reduce the cost of 
logging but will delay the cutting of the second half of the area until 
the trees on the first half become large enough to furnish the neces- 
sary seed for reproducing it when 
cut oyer. This will delay the sec- 
ond cut to between the sixtieth 
and seventy-fifth year and require 
a rotation for each half of the stand 
of from 120 to 150 years. Com- 
plete stocking on the entire 300 
feet of clearing could hardly be 
expected short of 3 and possibly 4 
seed years; that is, from 15 to 18 
years. Birch, aspen, beech, maple, 
and other hardwoods, and rasp- 
berries and other perennials will 
almost surely come in during the in- 
terval, whether the area is burned 
over or not . Spruce, however, will 
seed in beneath; and while that 
which comes in first where the 
cover crop is dense willbe retarded, 
that which comes in later will find 
conditions favorable to its rapid de- 
velopment, so that when the over- 
wood thins out, this understory of 
spruce will develop largely as an 
even-aged stand. (See Fig. 2a.) 
The most desirable of the hard- 
woods as a nurse tree for spruce is 
the aspen. It also reaches such a 
size as to enable it to be cut at a 
profit within from 40 to 50 years. 
Its coming in, therefore, should be 
encouraged. This can best be ac- 
complished by the broadcast burn- 
ing of the brush in the early spring 
following the logging. The seed 
of fire cherry is dispersed in the 
summer and of beech, paper birch, 
and sugar maple in the fall and 
winter, while that of the aspen is 
dispersed hi the early spring. Broadcast burning in the spring, there- 
fore, as soon as the brush is dried out enough to burn readily, will 
destroy the duff and the seeds and spring germinates of the other 
