14 -BULLETIN 154, U. S. DEPARTMENT OF AGRICULTURE. 
EFFECT OF FIRE. 
Fire has been one of the most important agencies in the reproduc- 
tion of lodgepole pine. Its effect is fourfold: (1) By softening the > 
resin and drying out the cone scales it opens the sealed cones’and - 
makes available the accumulated seed production of many. years; 
(2) by reducing the density of the ground cover it admits plenty of 
light; (8) by exposing the mineral soil and removing the ground 
cover it prepares a favorable seedbed; (4) by killingand driving away 
for a time the rodents and birds it saves the seed from being eaten. 
Thus aided by fire, lodgepole has been able to replace to a consider- 
able extent all the species within its range, since these usually pro- 
duce seed in abundance only once in several years and discharge it 
immediately. Most of the extensive lodgepole stands now in existence 
have come in as a result of fire. On the other hand, areas formerly 
covered with lodgepole have been made barren by “ double burns,” 
where stands of young growth which followed the first fire have been 
destroyed by a second one before they were old enough to produce 
seed. Areas of this kind on which all of the trees have been killed 
will not reforest naturaliy for many years, since the only way repro- 
duction can take place is by seeding from the sides. 
Fire in a mature stand is usually followed by too dense a reproduc- 
tion to permit the most satisfactory development of-the young trees. 
Sample plots on the Gallatin National Forest, Mont., show repro- 
duction after the fires of 1910 with a maximum density of about 
300,000 one-year-old sedlings per acre. On the Deerlodge National 
Forest stands following fire have been found which, at the age of 8 
years, had a maximum density of about 175,000 live seedlings per 
acre, averaging about 2 feet high. Ten small sample plots on the 
Arapaho National Forest, Colo., in a 22-year-old stand, showed an 
average of nearly 44,000 trees per acre. These figures, of course, rep- 
resent maximum densities on small areas, but as extreme illustrations 
they show that severe overstocking is more than likely to follow fire. 
The effect of fire on cut-over areas may be very different. Where 
all the trees have been felled and the brush piled in windrows—a 
practice in many private operations—a fire in the slash may be fol- _ 
lowed by reproduction of moderate density. Such a fire usually de- 
stroys all the seeds in the windrows, the locations of which are marked 
by the absence of reproduction, while a moderately dense stand starts 
in the intervening spaces from cones which did not get into the 
windrows and thus escaped destruction. 
On unburned, cut-over areas reproduction is apt to be much less 
dense, and therefore more satisfactory than in the case of burned- 
over uncut stands. Throughout the Rocky Mountains are thousands 
of acres of old cuttings, untouched by fire, upon which the repro- 
duction is decidedly satisfactory. This is-especially true of the Deer- 
lodge Forest, near Butte, Mont., where it is unusual to find an old 
