ROLE OF FIRE IN CALIFORNIA PINE FORESTS 31 
The last step in the process of attrition, the ultimate effect of 
repeated fires, is the complete destruction of the productive capacity 
of the site. This ultimate result will be discussed later in consider- 
ing the effects of fire in the brush fields. 
FIRE IN SECOND-GROWTH STANDS 
In discussing the fire damage to second-growth stands, only those 
are selected for study that have followed the cutting of virgin timber 
and have attained a size sufficient to justify their exploitation for 
saw timber. This rather restricted selection is advisable because in 
the California pine region there are extensive areas of such second 
growth, which followed the cutting of the virgin forest in the early 
mining days from about 1850 to 1870, and these stands are now 
being logged. Of the total forest area of the region these stands 
form but a minor portion; but they have a as atin very much 
ereater than their area alone would indicate, for they represent the 
type and kind of forest that will become increasingly abundant as 
the virgin forest is removed and new stands take its place. These 
stands differ profoundly in many ways from the virgin forests, and 
in no way more than in their reaction to forest fires. 
THE CROWN-FIRE HAZARD 
The virgin forest is uneven-aged, or at best even-aged by small 
sroups, and is patchy and broken; hence it is fairly immune from 
extensive, devasting crown fires. Extensive crown fires, though 
common in the forests of the western white pine region,’ are almost 
unknown in the California pine region. ane crown fires may extend 
over a few hundred acres, but the stands in general are so uneven- 
aged and broken and have such a varied cover type that a continuous 
crown fire is practically impossible. A rare exception was the Ege 
Lake fire on the Modoc National Forest, where one area of 92 acres 
was destroyed. In general such stands are immune, but immunity 
to crown fires does not extend to second-growth stands, cut-over 
areas, or restocking brush fields. 
Existing second-growth stands are typically even-aged and fully 
stocked, have a continuous, unbroken canopy, and are consequently 
susceptible to the most destructive type of forest fire. To those 
familiar with the occurrence of crown fires in the dense even-aged 
forests of western white pine and Douglas fir in the Pacific North- 
west a field examination of the second-growth western yellow pine 
forests of California would be immediately convincing that these 
stands also represent an exceedingly high inherent hazard, and that 
this hazard differs from that of the virgin forest. (Pl. V, fig. 2.) 
The most extensive second-growth stands are in the Mother Lode 
region of the Sierras, centering around Nevada City. It is in this 
vicinity that the result of fires has been most carefully studied. 
For many years the practice on some of the private lands has been 
to allow light fires to run through the second-growth forest, either 
8 The western white pine region includes northern Idaho and northwestern Montana, where the western 
white pine (Pinus monticola) grows in dense, uniform stands over large areas. é 
2The Mother Lode region is the rather narrow belt lying along the edge of the central Sierras, where 
gold has been extensively mined. 
