NATURAL REGENERATION OF DOUGLAS FIR. ao 
with a good stand of young Douglas fir and associated species. In 
September, 1915, this area was reburned. The second fire did not 
kill any of the trees that had been left alive by the 1902 fire, but 
it destroyed all the young growth on the area. Forty-five plots, 
each 1 rod square, were laid out after the fire of 1915, and definite 
records were kept of the germination and survival of seedlings fol- 
lowing the second burn. Little reproduction was found on the area 
at distances more than 38 chains from seed trees, although stands 
of Douglas fir containing 8,640 seedlings per acre followed the sec- 
ond burn at distances within 2 chains of groups of seed trees. A 
few single green trees were scattered at distances of 15 to 20 chains 
from the groups of seed trees and near some of the reproduction 
plots. The plots near these seed trees did not have more seedlings 
than those at greater distances, although these seed trees were 
known to have produced seed crops. Undoubtedly the seed crops 
were gathered and destroyed by rodents. On a near-by flat area, 
burned at the same time, scattered reproduction occurred under the 
remaining seed trees, and none at distances of 4 chains or more from 
them. 
On all the areas that have been studied, where two or more fires 
have occurred, it has been found that the young growth following 
the second or later fires either occurs only in the immediate vicinity 
of seed trees, or the seedlings are scattered over great distances 
but occur only occasionally. Such reproduction may come from 
seeds that have been transported for long distances by wind or 
birds, or it may have come from seeds that have passed through 
exceptionally long periods of dormancy. The averages of the areas 
studied where reburns have occurred are given in Table 13. 
The contrast of the stands of young growth after the first burn, 
with the almost complete failure of reproduction after repeated 
fires, is evidence that the sources of seed for the two stands could 
not be the same. The reproduction near the green timber in areas 
burned twice or more has evidently come in large part, or entirely, 
_from seed trees, as indicated by the rapid decrease in the number of 
seedlings as the distance from seed trees increases. _ 
TABLE 13.—Average number of Douglas fir seedlings per acre after one forest 
fire in which all timber was killed* and on the same areas after they were 
reburned 10 to 15 years after first fire.’ 
Afterone| After Afterone| After 
Distance from seed trees. forest reburn- Distance from seed trees. forest reburn- 
fire. ing. fire. ing. 
Wiehe: ye oe ee casas 7,100 The PR MALLS AeA ONSIUe Base aie een te i o¥35020 9 
ZRONUALNS Se eera safe tec ante an 5,360 Dis CHALNS HS Neha Ane Seay 3,000 0 
S CHARIS "452. ufed Ser tenet ks 9, 660 ABO yl lsichainsie sy mea 4S a. fk 4,175 9 
ACHAMIS. 2) ie Noose eet 3,490 DAM CHAINS Maen Geiss cin wien | 770 8 
SCHAMISH Iasi d Eee 1,990 PRA Uo CHatOS ty: £/338 100 SS 2 22 ar | 195 8 
19 0 aE Re as See oe ae 6,310 GAO Chains sass nee: cao n | 400 7 
MCNSINS SS seat be cease eee eee 3, 800 AO VEN CMAIISs Seni uewee . cee 500 0 
Schaims: serie? ee ery 800 AGS HES chains: § <5 jess ae bossa | 6, 850 0 
DCN aS eo ot on aha (ry see ee 2,030 | s 22M AO CHATS YW feats a since Sam | 8, 820 6 
TO ichains. VOLE See 2,455 AS P20 Chaim See NR ey eee | 4,840 3 
| 
! Examined 5 to 12 years after fire. 
_? Based on 172 square-rod plots examined annually for from 2 to 5 years, and on 3.75 miles of belt transect 
line examined from 1 to 5 years after the second fire. Areas at more than 20 chains from seed trees that 
had been reburned, of which previous records were taken, were not available. Plots were arranged in 
Series running out from seed trees; consequently results from plots and transects could beaveraged together. 
3 1 chain equals 66 feet; 10 chains equals one-eighth mile.  - 
