NATURAL REGENERATION OF DOUGLAS FIR. 19 
An arbitrary section, chosen to include Lookout Mountain, was 
studied intensively by a gridiron system of belt transects, which 
were run 24 chains’? apart over the entire section. Then, with this 
section as a hub, a township surrounding it was studied extensively. 
For this study eight transects were run radially from the centers of 
the four sides and from the four corners of the section to the cor- 
responding points in the township. Wherever a solid body of green 
timber was encountered the transect was discontinued. These beit 
transects served effectively to disclose the distribution of reproduc- 
tion over the entire township. The plan of the survey is shown in 
Figure 3. The lines radiating from the center section represent the 
transects which were run in making the study of the township. 
There was little young growth on the south and east slopes of 
Lookout Mountain, and such as did occur was confined to the draws 
below the barren slopes. On the north and west slopes, however, it 
was uniformly scattered. This distribution of the young growth is 
due to the local topography. The fire approached the mountain 
from the southeast and swept up these slopes with unusual inten- 
sity. After the fire the south and east slopes were hot, dry sites 
and were consequently unfavorable to the establishment of seed- 
lings. On the other hand, on the north and west slopes not only 
was the fire less intense, but the site was inherently more favor- 
able to seedling growth. | 
The most significant facts are found in the distribution of the 
age classes and their relative proportion, as shown in Table 9. This 
table shows that 58.9 per cent of all Douglas-fir seedlings germinated 
the first year after the fire, 28.7 per cent 2 to 6 years after the fire, 
and 12.4 per cent 7 to 11 years after the fire. 
Taste 9—Classification of young growth according to age classes and distri- 
bution on section studied in Yacolt burn.* 
Percentage of total 
number of seedlings | Percentage of all¥seed- 
in each age class lings found, according 
Percent-| found within each to age classes. 
age of distance. 
Distance toe 
Species. ftom seca examined| Time of germination. | Time of germination. 
ees. | included 
in each 
distance.| First | 2to6 |7tol1| First | 2to6 | 7tolt 
year | years | years ; year | years | years 
after aiter after after after after 
fire. fire. fire. fire. fire. fire. 
Chains. 
Over 10... 79.0 61.1 38. 2 0.7 | 
Douglas fire sees AU sees GEO Ohi 9.7 48.1 33.3 18.6 58.9 28. 7 | 12. £ 
Oltoras=: 10186} 67.6 14.6 17.8 
c Over 10 100.0 15.8 BAD i ee eat aes 
Western white pine............ i COpLON a. Himes mie IRN INO Fe al lg gh LOW SW AGN eaten sa 
ONC ORS Meee sl fed eet aS essa Nees el RS Taee el GA UN late GUS | 
Over 10... 64.2 | 96.0 Ba) JC 
IN ODIG fir see see ae Nie OtoplOzz ae: 20.4 | 90.0 5.4 4.6 87.5 6.0 6.5 
(0) 760) WE See 15.4 76.5 9.4 14.1 | 
1 Over 10. 56.6 | 87.9 10.2 1.9 
Silver fin ssa eee se ace i COM ONsese 24,4) 71.5 18.7 9.8 71.5 As 11.2 
Opto LOFON moos 22.9 22.0 
Over 10. $2.0 36.8 57.8 5.4 
Western hemlock.............. 3 fe LOPS ShO Rea 76.9 23.1 18.4 67.4 14.2 
50) aged is 0S ae ea al 
@ The total area included in transects was 18.6 acres. 
b One chain equals 66 feet; 10 chains equal one-eighth mile. 
2 One chain equals 66 feet. 
