June 21, 1024 
A Study of Douglas Fir Reproduction 
1241 
formancc of Douglas fir and Engelmann spruce seedlings upon the shelterwood 
plot. In every instance, the clear-cut, selection, and original stands rank in 
order downward for each species. 
GROWTH OP LIMBER PINE SEEDLINGS 
UNDER VARIOUS SILVICULTURAL METHODS AND IN 
0 l 2 3 4 5 6 7 8 9 
Height of Seed lings “ Inches 
Fig. 3 
SUPERIORITY OF SHELTERWOOD 
For the past few years, the most striking fact noted in connection with the 
reproduction upon the plots has been the superior development of the young 
trees under the shelterwood cutting. This good growth is not confined to any 
one section or sector, but characterizes the young trees of both Douglas fir and 
Engelmann spruce over the entire area. It is rather difficult to place the respon¬ 
sibility for this better development upon any of the conditions which establish 
this plot as superior to the selection plot. In order to determine the relation 
between growth rates under the various methods of treatment, the seedlings 
on at least one half of the sections of each plot and all of them upon the clear-cut 
plot were measured in 1923. At the same time, the depth of humus was measured 
as near each seedling as could be done without disturbing the young tree, and the 
age of each tree was also determined. 
On both slash-scattered and slash-burned areas under the shelterwood cutting, 
the Douglas fir seedlings averaged larger than on any of the other plots. Upon 
the slash-scattered area their average height was 3.53 inches, as against 2.66 
inches for the clear-cut area, and 2.15 inches for the selection. Upon the slash- 
burned area, the respective heights in the same order were 3.12, 2.70, and 2.70 
inches. The average height of fir seedlings under the old stand was but 1.49 inches. 
These figures represent groups varying from 40 to 341 seedlings, with average 
ages varying from 5.40 to 6.05 years and uniformly greater upon the slash-scattered 
areas. Curiously, the seedlings under slash on the shelterwood plot were larger 
than those under piling and burning, which was not the case with the selection 
