2 4 
Journal of Agricultural Research 
Vol. XI, No. i 
(2) The irregular, dense stands of young growth are due to seed 
stored in the forest floor or in cones. This seed retains its viability 
through the fire and is responsible for the dense reproduction that 
springs up after the first fire. 
(3) The even-aged stands of reproduction immediately following a 
fire, regardless of location of remaining seed trees, the irregular alter¬ 
nation of dense stands of reproduction with grass areas, and the failure 
of reproduction on areas burned over by a second fire before the stand 
reaches seeding age or by consuming all of the duff and precluding any 
possibility of seed remaining after the fire, all point to the seed stored 
in the duff as the principal source of seed responsible for the restocking. 
(4) The ability of the seed to retain its viability when stored in the 
duff or when retained in cones during fires has been further demon¬ 
strated by recovering and germinating seed from duff under forest con¬ 
ditions and by recovering and germinating seed from cones which passed 
through a crown fire. 
PRACTICAL VALUE OF THE RESULTS 
The fundamental facts of seed storage and viability brought out by 
this study have thrown new light on the whole question of natural 
reproduction. 
The even-aged second growth stands of Douglas fir which are the 
general rule throughout the Pacific Northwest are due to seed stored 
in the ground. It has been clearly shown that these even-aged stands 
could not be produced by the seed scattered by the remaining seed 
trees. The distance of effective migration during each generation is 
usually only from 150 to 300 feet, varying with the adaptation of the 
seed for wind distribution. Migration due to other agencies than wind 
is responsible for individual seedlings far from the parent tree. Such 
individual seedlings, however, are of no practical significance in restock¬ 
ing large areas. 
The establishment of a forest by means of wind-disseminated seed 
is a slow process; and with only this means of succession practically 
all of the large bums would be denuded areas or would support but a 
few scattered trees, until several generations of these trees, grown with¬ 
in these areas, could again restock them. This would inevitably pro¬ 
duce an uneven-aged and irregular forest; yet the stands which follow 
most of the bums are even-aged. When a forest is destroyed by fire 
or cutting and is replaced simultaneously over large areas, the succes¬ 
sion depends upon the seed produced at the time of or before the de¬ 
struction of the forest and the ability of the seed to retain its viability 
through the period of destruction, whether by fire or cutting. This 
form of succession is the replacement of a forest almost immediately 
by the same species which comprised the original stand and usually in 
the same proportions. 
