ROLE OF FIRE IN CALIFORNIA PINE FORESTS 25 
FUNCTIONS OF ADVANCE REPRODUCTION 
Two general functions of advance reproduction in the virgin forest 
are to be noted. First, in timber that will not be cut over for many 
years to come, the advance reproduction will fill in the blanks of the 
present forest and will in many cases attain sufficient size to increase 
the yield of the stand when it is cut. Even in comparatively fully 
stocked stands under protection, gaps may thus be filled, as single 
mature or overmature individuals succumb. Reproduction is assur- 
ance that the growing capacity of the land will not lie idle. In other 
words, the virgin forest is not in a static condition; changes are tak- 
ing place constantly, giving constant SRpaubEnien to new growth. 
The second function is in evidence when the virgin forest is to be 
harvested within a reasonably short period and some provisions must 
be made for continuing the forest without resorting to planting. 
Dunning’s investigation (8) shows clearly that by far the most cer- 
tain, safest, and quickest method of getting a new stand in the Cali- 
fornia pine region is to preserve the advance reproduction in the log- 
ging operations. Depending on seed trees alone is likely to lead to 
a serious delay in obtaining a new crop. Oncuttings on private land 
where no provision is made for seed trees and where the land is prac- 
tically clear cut, advance reproduction is the only assurance that a 
new forest will follow the old. 
What effect even a single surface fire will have on young growth in 
the virgin forest is therefore not merely of academic interest, but is 
of truly momentous importance. 
ACTION OF FIRE 
There has been a great diversity of opinion regarding the physical 
effects of fire on reproduction in the virgin forest. Some who have 
wished to emphasize the destructiveness of fire have assumed that 
the mere occurrence of even a light fire resulted in complete oblitera- 
tion of the young trees over large areas, although the very persistence 
of the virgin forest in the pine region in spite of repeated burns is 
prima facie evidence that such is not the case. On the other hand, 
those who have desired to minimize the damage to reproduction from 
fire have taken the position that fire is a positive benefit through its 
alleged action in thinning the weaker and smaller individuals out of 
the dense thickets. ‘The present investigations indicate that the 
truth lies between two extremes, and a fire of this nature is neither a 
catastrophe nor a blessing. 
In the examination of the Ham Station fire, reproduction plots 
were tallied at intervals along a cruise line. It was found that on 
an average the reproduction before the fire was 66 per cent complete 
and that after the one fire the degree of stocking had been reduced 
to 40 per cent. Using only this one illustration for the present, it 
may be pointed out that even fires that result in material damage to 
merchantable timber, as this one did, fortunately do not entirely 
wipe out advance reproduction, even that of small size, over extensive 
areas. On this 9,000-acre burn the effect of the fire on advance 
reproduction was very similar to the effect on large timber; that is 
intense damage on many plots of a few acres each, where the young 
erowth had been completely destroyed, coincided with areas of heavy 
