ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

INTRODUCTION
Many western larch (Larix occidental is Nutt.) forests began as a result of
catastrophic fires that f-ed years in which litter and other flamnable debris
had accumulated within maturing stands. Western larch, the most shade-intolerant
species in the Northern Rockies, requtres a major disturbance for successful regenera-
tion (Schmidt and others 1976). Indeed, fire-exposed soil s enhance the regeneration
of most conifers in the western larch-dominated forests.
Experience has shown that western larch can be regenerated using any method of
management that favors even-aged stands if: (1) soil is exposed through prescribed
burning or scarification, (2) seed 9 s present, and (3) favorable microsi te conditions
occur during the year of germination (Schmidt and others 1976). Regeneration of
shade-intolerant species such as western larch is less certain when land managers
face the need to modify cuttirg practices, util ization standards, or seedbed
preparation methods to protect or enhance other mu1 tip1 e-use values by reducing
disturbance of the site.
OBJECTIVES
The problem faced in this study was to identify: (1) silvicul tural systems
that enhance natural regeneration of western larch and its associated species, and
(2) sites where conifer stockin could be increased through planting Engelmann
spruce (Picea en elmannii Parry 7 +
, and Douglas-fir (Pseudotsu a menziesii vsr.
glauca ( ~ e j s s n No k western larch planting stoc was m.
The objectives of the reseneration portion of the R&D Program were to evaluate
the ways in-which sil vicul tural prescription, harvesting methods, and forest products I
residue reduction treatments affected the regeneration of western 1 arch and asso-
ciated species.
STUDY AREA AND TREATMENT
The study was conducted on the 7,460 acre (3019 ha) Coram Experimental Forest,
on the Flathead National Forest In northwestern Montana (fig. 1 ). The sbudy sites
were locahed below the main rldge facing east into Abbott Basin (lat. 48 25' N.,
long. 113 59" W. 1, Six blocks, (fig. 21 were logged in 1974, including two clearcuts
(14 and 17 acres or 5.7 and 6.9 ha), two shelterwoods (35 and 22 acres or 14.2 and
8.9 ha), and two sets of eight small clearcuts representing group selection cuts
(averaging 0.8 acre, or 0.3 ha). Each block was further divided into four subblocks,
each of which received a different standard of timber and residue utilization (fig;
1). Of the four subblocks, No. 1 and 2 were broadcast burned and No. 3 and 4 were
left unburned. A description of the util ization standards and tree cuttfng require-
ments follows: