ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

SHELTERWOOD CUTTINGS
The number of 3- and 5-year-old seedlings was greater on the shelterwood cuts
(table 3) because of the greater protection on that site. The lower shelterwood site
had nearly the same number of seedlings and level of stocking throughout the study
because the planned fire treatments had not been applied. The upper shelterwood site
had more seedlings and greater stocking on the burned seedbed than on the unburned
area.
GROUP SELECTION CUTTINGS
The group selection cuttings regenerated poorly during the five years following
timber harvest (table 4). The possibility of any sudden increase in stocking seems
remote because of the heavy vegetative competition on 41 1 seedbed condi ttons. About
the same amount of western larch and Douglas-fir seed fell on both the lower and
upper group selection cuts from 1974 through 1977. The lower groups also had heavy
western hemlock and western redcedar seedfall in 1976. Practically no hemlock or
redcedar regeneration from the 1976 seed crop was found in September 1979..
CLEARCUTTI NGS
The number and stocking of 3- and 5-year-old seedlin s in 1979 was greater on
the clearcuts (table 5) than on the group selection cuts 9 table 4), but less than on
the shelterwood cuts (table 3). Most seedlings were found on the burned seedbeds.
The number of seedlings found on "the upper clearcut decreased with distance from the
lower timber edge, corresponding with the seed dispersal pattern. This relationship
did not hold on the lower clearcut, however, probably because of greater competitTon
for moisture by dense vegetation on the 'lower portion of the clearcut.
Seed Gemination and Seedl ing Survival
From 1975 through 1978, germination of sown seed on unburned seedbeds was poor
for all species except subalpine fir. In contrqst, germination improved greatly for
all species on the seedbeds that were burned in 1975 (table 6). Survival of seedlings
was usually much higher on burned seedbeds than on the undisturbed forest floor. For
example, in October 1976, subalpine fir that had germinated the previous May and June
averaged 23 percent survival on burned seedbeds, compared to 5 percent on the undis-
turbed forest floor. Because of consistently low germination for other species,
similar comparisons were not made for those species.