NATURAL REGENERATION OF DOUGLAS FIR, 2k 
fir seed trees within 2 or 3 chains of the northeast corner of the sec- 
tion on the northwest slope of Little Lookout Mountain. These trees 
were from 100 to 300 feet, above the areas on which germination 
occurred 7 to 11 years after the fire; hence it 1s entirely possible that 
they were responsible for the occurrence of this age class in the north- 
ern part of the section. The limited distribution of this same age 
class, with reference to seed trees and topography, was consistent 
throughout the section and was particularly conspicuous at several 
points in the township. (Vig. 3.) 
The transect from the west-central point of the section passed 
within -2 chains of green timber. The influence of this timber is 
shown in Figure 3 by the appearance of young growth which germi- 
nated 7 to 11 years after the fire for a distance of a few chains from 
the seed trees in Texas Gulch. The remainder of the transect had 
a scattered stand of reproduction of the older age classes. A very 
| dense stand occurred in Poison Gulch almost a mile from the nearest 
- seed trees. This same condition is illustrated on the southwest tran- 
sect, where the young growth of the older classes is very heavy along 
the north slope of Bear Creek Canyon at a distance of more than 
a mile from the nearest Douglas-fir timber. As the transect ap- 
proaches the timber at the top of the ridge, older seedlings are again 
found scattered here and there, and it is only close to the edge of the 
timber that the younger seedlings begin to appear at all. This pecul- 
iar distribution of the reproduction may be observed on all of the 
transects, and shows definitely that the green timber remaining after 
the fire has had little influence on the general occurrence of the 
Douglas-fir reproduction over the burn. 
The foregoing facts first cast a doubt upon the long-accepted 
theory of the restocking of large forest burns by the process of 
wind dissemination of seed and finally proved it untenable. As the 
study progressed and this fact grew steadily more convincing, the 
question naturally arose, ‘“ What was the source of seed for all this 
reproduction?” The answer to this question developed with the 
accumulation of evidence throughout the burn. It was found that 
the reproduction most often occurred, not in a solid unbroken cover, 
but in different-sized patches with irregular and ramifying bound- 
aries. Where the reproduction was lacking, the ground was coy- 
ered with grasses, herbaceous plants, and shrubs, evidencing an un- 
interrupted growth since the burn was formed. The occurrence 
| of these two types of cover made an interlaced pattern over the 
entire burn, although one type or the other often expanded solidly 
j over a slope or basin many acres in extent. Everywhere the feature 
that was most striking was the sharp line of demarcation between 
the reproduction and the grass areas. For all its tortuous wind- 
ings the boundary was always distinct. 
Obviously such a condition could not have resulted from natural 
seeding, but must rather have been produced by some force acting 
on the surface of the ground. The idea of ground fire suggested 
itself. One who has seen ground fire burning in forest duff will 
| remember that it burns irregularly, leaving here an island and there 
forming a deep bay between two points of unburned ground. When 
| at length the smoldering fire is stopped, the result is just such a 
| mosaic of burned and unburned surface corresponding to the mosaic 
