A STUDY OF DOUGLAS FIR REPRODUCTION UNDER 
VARIOUS CUTTING METHODS 1 
By Jacob Roeser, Jr., Forest Examiner , Fremont Forest Experiment Station, 
Forest Service , United States Department of Agriculture 
In the fall of 1913, four plots, each 200 by 200 feet, and subdivided into 
20-foot sections, were laid out in a typical Douglas fir ( Pseudotsuga taxifolia) 
stand in the vicinity of the Fremont Forest Experiment Station, on a north 
exposure, with a fairly uniform slope of approximately 35 per cent and an eleva¬ 
tion of 9,100 feet. The merchantable stand was approximately 265 years old 
and consisted of Douglas fir and Engelmann spruce ( Picea engelmanni) in mixture 
with some limber pine ( Pinus flexilis), western yellow pine (P. ponderosa ), and 
aspen ( Populus tremuloides) . Approximately 78 per cent of the larger-sized trees, 
over 6 inches in diameter, were Douglas fir, while only 29 per cent of the smaller 
trees were of this species, indicating a gradual replacement of the fir by the 
spruce and a general tendency toward an ultimate spruce type. The soil on the 
plots is a granitic gravel. 
The four plots, arranged from west to east and separated by 40-foot isolation 
strips, were prepared as follows: 
No. 1 was clear cut; No. 2 was left in its original condition to serve as a control, 
with 1,145 trees of Douglas fir, Engelmann spruce, limber and yellow pine, aspen, 
and willow ( Salix sp.) of all ages comprising the stand; No. 3 was cut under the 
shelterwood plan, removing all but 83 of the thriftiest mature Douglas firs, 
which were well scattered over the area and in 1916 averaged 9.95 inches in 
diameter breast high; while plot No. 4 was cut as nearly under a selection system 
as the condition of the stand would permit. Two hundred and seventy-one 
Douglas firs were left, representing all sizes from 4} feet high to mature trees. 
While the original stand was by no means even-sized, it was to a large extent 
even-aged, and many, if not most, of the small trees left were merely small 
through long suppression. 
Following the cutting operation, all reproduction below 4$ feet in height was 
removed so as not to interfere with future counts. 
In order to study the effect of different methods of slash disposal upon the 
character of the reproduction secured, the slash left after logging on the eastern 
half of each of the three cut-over plots was scattered over the ground, while that 
on the western half was piled and burned. 
The first reproduction count was made in the year 1915, but was only partially 
completed because of the advent of bad weather. A complete count was made 
in 1916. No counts were made in 1917 and 1918, although casual observations 
during 1917 showed no new germination had come in, and that most of the 
1916 germination had disappeared. 
In the summer of 1919, a fairly complete study, including reproduction counts, 
tree measurements, the relation of brush, humus depth, grass, and root length 
to reproduction and survival, and observation of climatological conditions, was 
made and reported upon, and every fall since then reproduction counts have 
been made on 22 of the 20-by-20-foot sections located in diagonal strips across each 
plot, running S. 45° W. up the slope, and representing an average of all surface 
1 Received for publication June 19, 1924—issued Nov., 1924. 
Journal of Agricultural Research, 
Washington, D. C. 
( 1233 ) 
Vol. XXVIII, No. 12 
June 21, 1924 
Key No. F-18 
