32 BULLETIN 1294, U. S. DEPARTMENT OF AGRICULTURE 
in the spring or in the fall after the first heavy rains. Fires of 
this character, far from protecting the stand from fire damage, — 
rather increase the hazard. What this hazard is, isshown by several — 
examples of just such areas where crown fires have developed with 
disastrous results. ) 
The largest burn in second growth of this sort which was studied 
was the Rock Creek fire near Nevada City, Calif., which burned — 
from September 1 to 6,1910 (8). The following sample plot is — 
representative of conditions on this area: | 
SaMPLE Puiot oF Rock Creex Fire, 1910 
(SW. 2 NE. i sec. 32, T.17 N., R.9 E., M. D. M., near Nevada City) 
Area.—1 acre. 
Slope.—3 to 5 per cent, north exposure. 
Condition at time of examination, December, 1919: 
Timber— 
172 western yellow pines, 5 to 18 inches diameter breast high, killed. 
28 incense cedars 5 to 8 inches diameter breast high, killed. 
3 yellow pines 12 inches diameter breast high, alive. 
2 incense cedars, 7 to 9 inches diameter breast-high, alive. 
Reproduction— 
1 western yellow pine seedling, alive. 
8 Black oak coppice sprouts, alive. 
Cover.—Abundant stand of manzanita (Arctostaphylos patula) 3 to 5 feet high, 
deer brush and buck brush (Ceanothus integerrimus and C. cordulatus) 2 to 3 
feet high, dense mat bear clover (Chamaebatia foltolosa) $ to 1 foot high. — 
Hazard.—All trees killed, except two cedars, had rotted and fallen, covering the 
ae with a tangle of logs, bark, and limbs. A summer fire would spread 
rapidly. 
This fire burned a strip, 34 miles long and 14 miles wide through — 
the center of a practically continuous tract of 40-year old second- — 
erowth western yellow pine which had been regularly light burned. — 
The total burned area was 2,840 acres, of which 2,160 acres were 
timbered with this splendid second growth that averaged as high as © 
20 cords of wood to the acre. A cruise of the burn showed that on 
more than 75 per cent of the total area all trees were killed, except 
occasional isolated clumps. This fire spread through the crowns, 
utterly destroying the timber on all slopes and exposures, and resulted 
in the reversion of the burn to a worthless brushfield. At the present 
time the area is occupied exclusively by a dense stand of a number 
of brush species (Arctostaphylos patula, Ceanothus integerrimus, C. cor- 
dulatus, Arbutus menziesii, etc.), and hidden by this brush is a tangle 
of rotting logs and chunks of trees, the remains of the former forest. 
The destruction by this single fire was almost complete and far exceeds 
anything known in the virgin forests either in this particular locality 
or any other part of the pine region. 
Another destructive fire in a second-growth western yellow pine 
stand occurred near Groveland in 1917. This crown fire destroyed 
the stand on an area of 100 acres. Another similar crown fire during 
early May, near the Pilgrim Creek nursery on the Shasta Nationa 
Forest, wiped out the stand on 150 acres, although banks of snow 
were still present. 
