34 BULLETIN 1294, U. 8. DEPARTMENT OF AGRICULTURE 
Moreover, seed is not borne in appreciable amounts until the stand 
is at least 60 years old, az d climatic conditions for the establishment 
of reproduction are critical at best. The reestablishment of a forest 
in a brush field is a long, slow process, for seed is scarce, rodents are 
abundant, and seedlings must compete for moisture with established 
vegetation during a long drawn out dry season. Crown fires in 
California are serious, therefore, even more because they render forest. 
land nonproductive than because they result in great destruction of 
merchantable material. As the cutting of the virgin forest proceeds 
and the area of second-growth stands is correspondingly increased, the 
problem of preventing serious damage by forest fires and, more 
important, of preventing devastation of forest lands, will be infi- 
nitely more difficult than it is in the present virgin forests. Only 
more intensive management of the second-growth forests can min- 
imize the chance for extenisve conflagration. 
EFFECT OF REPEATED SURFACE FIRES 
While it is true that heat killing is the outstanding form of damage 
in a aa stands, there are other losses which can not be over- 
looked. 3 
Studies of the effect of repeated surface fires in second-growth 
stands show strikingly the same process of attrition that is known to 
have taken place in the virgin forest. Results of studies of several 
sample plots on private land are tabulated below: 
GRAHAM RaAncH PLotT, TAHOE NatTIonAL Forest (AREA 0.3 ACRE) 
History.—This area has been regularly “‘ light burned,’’ the last fire being in 1918. 
Slope.—30 to 40 per cent, eastern exposure. 
Stand.—73 live western yellow pines 5 to 24 inches in diameter (average 12 
inches diameter 50 feetin height); age about 50 years; base of crowns 15 to 
20 feet; one old western yellow pine 42 inches in diameter; 50 trees killed 
by fire were 3 to 5 inches in diameter, mostly suppressed and intermediate; 
charred stubs of limbs to within 6 feet of ground. 
Litter.—The average of the measurements showed 1.3inches depth. The upper 
layer was of newly fallen needles; the lower mat of partly decayed needles 
had not been burned by last fire. 
Ground cover.—80 per cent of the area was covered by bear clover averaging 6 
inches in height, 6 to 8 years old, which had only been scorched by the latest 
fires. 
Brush.—Manzanita 6 to 10 feet high, mostly dead, is found in all openings. 
These old bushes had not often sprouted, but abundant new manzanita from 
seed, 6 to 8 yearsold, and 3 feet high, had come in where there was sufficient 
light. There was also an abundant mixture of deer brush 1 to 2 feet high, 
originating mostly from seed and dwarfed by grazing. The brush was only 
slightly scorched by later fire. 
Reproduction.—There were no tree seedlings even in the openings, although the 
young trees were bearing seed, and a 42-inch western yellow pine was near. 
Scars.—11 trees, or 14 per cent of those alive, had five scars, many of them long 
ones, made largely by the fires of 1910,1913, and 1918. Many of these 
scars were still hidden by bark and were not noticeable unless the bark was 
knocked off. Woodpeckers have chipped off some of the bark around scars, 
indicating insect work. 
Kirr’s Area No. 1, Tanon Nationau Forest (ArzA 1 AcRE) 
History.—Intermittently ‘‘light burned’’; last burns, in 1919, very light and 
patchy; limbs left from wood cutting were not removed from the trees, 
and patches of inner bark had been killed at the base. 
