ROLE OF FIRE IN CALIFORNIA PINE FORESTS 49 
seedlings, saplings, poles, and brush. Where this increase does not 
occur, fires must be intense enough to consume entirely the plants 
killed. ‘The considerable damage to merchantable trees by such fires 
takes the burns quite out of the class of light fires. 
An additional source of increased fuel is the brush which sprouts 
soon after the parent stock is killed. On the area mentioned not 
only had practically all the stools sprouted after the fire, but the area 
occupied by brush had increased approximately 10 per cent. The 
sprouts had attained an average height of from 3 to 5 feet within 
five years, so that the amount of this new material was fully as 
great as before the fire. 
As was to be anticipated, this light burning, with all the costly 
precautionary measures, resulted in no appreciable damage to mer- 
chantable timber, for only one mature western yellow pine tree was 
found burned down. ‘The fire was so light and so patchy that in few 
spots had damage to any reproduction other than seedlings taken 
place. Where small seedlings alone occupied burnt areas, they were 
almost entirely killed; but in some of the dense pole and sapling 
thickets the fire had beneficially thinned out the smaller and weaker 
trees. Considering the effects of the fire over the entire area, the 
data collected showed clearly that the degree of damage was not 
serious. 
The most important conclusions to be derived from the study of 
this operation may be summarized thus: This area had not been 
subjected to fire for at least 20 years before the light burn, and there- 
fore represented a typical degree of hazard under protection: Five 
years after this operation, which, though it caused a minimum of 
damage, probably cost at present wage scales as much as $1 an acre, 
the amount of inflammable material on the tract was actually greater 
than before the fire. 
INFLUENCE OF TOPOGRAPHY—SIERRA COUNTY 
An area in Sierra County, covering parts of a 2,000-acre tract, was 
burned in the spring of 1912. Two Sen types existed here. The 
western yellow pine-Jeffery pine type, with a slight admixture of 
white fir, very similar to the Lassen County area, occupied the flat 
or very gently rolling lands. Much reproduction had come in since 
the inauguration of systematic fire protection, squaw carpet covered 
a large part of the ground, and the hazard waslow. Scattered brush, 
mostly in isolated clumps, was present, but nowhere made a contin- 
uous understory over on extensive area. The rest of the stand, a 
mixed coniferous type, in which the Douglas and white firs were 
heavily represented, occupied north and east exposures ranging from 
20° to 25° in slope. Large amounts of reproduction were present 
here, and with distinctly more brush than on the flats. ) 
The area was carefully studied in the fall of 1915, four growing 
seasons after the fire. No particular measures had been taken to pro- 
tect the individual trees, and the fire had been allowed to spread un- 
til it burned out at roads and other natural barriers. But that this 
had been a light burn was evident from the fact that in most places 
where the fire had spread it had consumed only the top layer of lit- 
2027°—24——4 
