June 15, 1925 
Natural Reproduction after Fires 
1197 
The outstanding and most extensive 
double burn of 1910 and 1919 on the 
Deep Creek area showed very scant 
new reproduction—from one to two 
new seedlings per acre on protected 
north and east aspects, and one or 
none on exposed aspects. There is 
much western larch reseeding on 
northerly aspects from parent trees 
which survived one or both of these 
fires. Numerous groups of seedlings 
8 to 13 years old occur in patches over 
this double burn, but only where the 
force and sweep of the last fire was less 
intense. After a period of about 20 
years these groups should produce 
seed, which will aid in restocking the 
double burns. Several groups of ma¬ 
ture trees were also found to have 
survived the two severe fires. These 
exist either on sharp knolls, on rocky 
spurs, or in deep draws. They are 
now supplying seed for restocking of 
the double burn at distances up to 9 
and 11 chains, mainly toward the 
north and east, in the direction of the 
prevailing wind. 
Close examination of the ages of 
white pine seedlings found on the 
various 1910 burns shows that very 
little germination takes place during 
the first and second year after the 
fire, and that the greatest number of 
white pine seedlings have become estab¬ 
lished during the fourth, fifth, and 
sixth years following the burn, prob¬ 
ably from seed buried in the soil by 
rodents previous to the fire. Later 
seeding is much less, in some years 
almost nothing, and is evidently due 
to distribution of the seed, in some 
cases for distances of one or more 
miles. An effort to correlate this later 
seeding with seed crops has not brought 
positive results, mainly because there 
is too much uncertainty regarding the 
local seed production in past seasons. 
Both the character and the scanti¬ 
ness of the vegetation observed on the 
large double burns of 1910 and 1919 
indicate very poor grazing values. In 
most places the vegetation is a help 
rather than a hindrance to natural 
reforestation. 
Subsequent to the large double burns 
of 1910 and 1919 there was but slight 
erosion, which took the form of deep 
gullying on lower north slopes. The 
most serious site deterioration was on 
the steep lower south aspects in the 
form of leaching or washing away of 
the finer loam and soil particles, leaving 
a relatively large proportion of rock 
and gravel and causing extremes of 
surface drought and heat detrimental 
to natural restocking. 
On the basis of these and previous 
studies, as well as from general observa¬ 
tion over a period of years, it is believed 
that there need be no concern about 
natural restocking after single burns 
in northern Idaho where forests of 
seed-bearing age are destroyed. Only 
one instance of failure of natural 
■’restocking has been found thus far 
namely, on the south aspect of John- 
igan Mountain on the Clearwater 
National Forest. There is, therefore, 
no necessity for artificial reforestation 
on single burns in northern Idaho. 
The situation on large double burns, 
however, such as those of 1910 and 
1919, clamors for thought and action. 
It would seem to be well to confine all 
efforts of planting to south and west 
slopes, in order to get the plants 
established before the site has deteri- 
.orated so far as to render artificial 
restocking difficult. 
The distribution of seed from groups 
of seed trees is directly applicable in 
silviculture, for it can safely be as¬ 
sumed that seed dispersal on cut-over 
areas will be more uniform and effec¬ 
tive than that shown on burns, mainly 
because the physical conditions of the 
site on logged areas are much less 
critical for seedlings than are conditions 
on double bums. 
The data on restocking from seed 
already on the forest floor at the time 
of the fire are not altogether safe to 
apply. We need to know more about 
the source of the seed which gives rise 
to the first cycle of reproduction on 
burns, and this can be determined 
only by the installation of permanent 
sample plots on fresh and large burns. 
In the application of the results to 
cutting practice, the point should be 
kept in mind that fires in virgin timber 
burn under different conditions than 
those on logged land. On logged land 
there is greater concentration of heat 
and more complete consumption of 
duff and other surface material than 
when virgin forests burn. It may be 
said, however, that indications are 
very strong, from the study of both 
logged and burned areas in the western 
white pine forests, that the seed which 
gives rise to the first cycle of natural 
reproduction is already in the duff at 
the time the mature seed trees are 
removed; but this can be proved only 
by the study of permanent sample plots 
o 
