June 1, 1925 
Reproduction of Engelmann Spruce 
1005 
noticeable that in the open spaces 
between groups of advance growth no 
seedlings were present even in the 
absence of a slash cover, notwithstand¬ 
ing the seeds that were without doubt 
showered upon the ground, for the 
spruce trees were bearing cones. 
Unfavorable surface soil conditions 
doubtless account for the absence of 
seedlings. As skidding had been done 
in the snow and the soil was not broken, 
an undecomposed duff layer covered the 
ground. It is also possible that the 
thin layer of twigs and leaves heated 
up so much in the sunlight that tender 
seedlings were unable to survive the 
heat. However, this can not be said 
to explain definitely the absence of 
seedlings, for more needs to be known 
of the temperatures which exist in this 
type of soil cover in the critical 
summer period. 
These two tracts furnishing evi¬ 
dences of unsuccessful reproduction 
following cutting are “ flats. 7 ' The 
indication is that spruce stands on 
flats must not be opened out suddenly 
if spruce reproduction is expected to 
return immediately in the succeeding 
stand. To insure the survival of 
Engelmann spruce, it is better to avoid 
this condition of wind-swept, dried-out 
layers of litter. 
Tracts on a northerly slope yielded 
somewhat different results. Repro¬ 
duction of Engelmann spruce was 
present in quantities sufficient for a 
satisfactory stand. Table V presents 
the findings on four plots selected as 
representative of the conditions on the 
northerly exposures. 
only partially in the reproduction, for 
the stumps show the stand to have con¬ 
sisted of a mixture of larch and fir 
predominantly, and of lodgepole pine, 
spruce, and alpine fir to a lesser degree. 
In the reproduction Engelmann spruce 
appears to be growing better under the 
more vigorous larch and lodgepole pine 
saplings. The soil here is covered by 
a thin layer of larch needles and twigs, 
which the spruce has evidently found 
favorable to survival. 
Another tract cleared up some of 
the perplexing features of the reproduc¬ 
tion of the Engelmann spruce. This 
lies also within the Great Northern 
Railway right of way. 
In building the railroad through this 
region a strip of forest fully 150 feet 
wide was cleared. The grade was built 
up with earth scraped out from the 
. sides, and taken from alternate 20 by 
20 foot squares along the track. In 
this manner the unbroken sod extends 
practically to the grade, save for the 
ditch, in alternate tongues 20 feet wide. 
The excavation squares were scraped 
down from 2 to 3 feet deep. Thirteen 
of these squares along the track were 
carefully examined. In all squares 
spruce seedlings 20 to 25 years old were 
found. In a few were lodgepole pine 
and larch seedlings, but no seedlings 
were found in the grass sod surrounding 
these excavations. A count showing 
the stocking of these squares is as 
follows: 
Engelmann spruce, 12 inches high and under.. 7 
Engelmann spruce, over 1 foot high_ 101 
Lodgepole pine, 12 inches and under_ o 
Lodgepole pine, over 1 foot high_ 3 
Other species----- 0 
Table V.— Average distribution of seed¬ 
lings per acre , by height classes, north¬ 
erly exposure , Xyack area 
Species 
12 inches 
high and 
under 
Over 1 
foot high 
Engelmann spruce. 
Western larch_ 
Douglas tir__ 
Other species.- 
Number 
Number 
512 
496 
224 
256 
256 
160 
80 
96 
Total 
1,072 
1,008 
This restocking came in on mineral 
soil exposed in clearing the right of way 
for the Great Northern Railway and 
on burned ground. It is to be noted 
that Western larch ( Larix occidentalis) 
and Douglas fir ( Pseudotsuga taxifoUa) 
form an important portion of the new 
growth. The original stand is reflected 
The largest trees were from 20 to 25 
years old. 
Between and beyond these squares, 
in which the mineral soil had been ex¬ 
posed, the unbroken sod areas extended 
to the edge of the right of way. On the 
grass sod no seedlings were to be found. 
Thus, of these two distinct kinds of 
surfaces, spruce was coming in at the 
rate of over 1,500 per acre on the min¬ 
eral soil, but in the grass not at all. 
The seed supply for both types of area 
was of necessity the same. Both areas 
were exposed to full light and no shade 
was cast upon either type during the 
hot hours of the day. The only vari¬ 
ables, therefore, were the soil surface 
and the moisture content. 
It may be concluded that the grass 
sod in this instance used up the soil 
moisture so completely as to exclude 
the tree seedlings. This appears to be 
the key to the problem of the repro¬ 
duction of Engelmann spruce. The 
