ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

of the commercial forest land in the region. In addition, the stand occurs on one of
the more productive Douglas-fir habitat types (Pseudotsuga menziesid/Vacc~n~m
caespihoswnl, and represents an operating situation and management opportunity in
which intensive utilization is likely to occur first. The mixed size and age classes
provide an opportunity for a range of silvicultural and utilization options.
Major management objectives for timbered 1 ands represented by the site include:
--reducing probability of catastrophic insect and disease
damage;
--achieving acceptable stand regeneration and development
and retaining species diversity;
--in parti a1 cuts, improvinq the residual stand through
selective thinning;
--protecting esthetic, recreation, and wildlife values;
--avoiding adverse biological impacts on the forest
ecosystem.
Harvesting treatments to be tested were developed to include combinations of
si lvicul tural practices, utilization level s, and post-harvest site treatments that
could be considered management alternatives. Silvicultural prescriptions applied
to harvest units included
(1) Selection cutting--harvesting approximately half of the
rnerchantabl e volume, 1 eaving a designated overstory o f
small saw timber and pole stems. Dense sapling and pole
stands were selectively thinned. The treatment repre-
sents current common practice in such stands.
(2) Understory removal --removal of approximately half of the
merchantable volume (and up to 213 of total cubic
volume), leaving a designated overstory of the better
sawtimber and large pole stems.
(3) Overstory removal --removal of a1 1 sawtimber trees and
thinning pole stands, leaving the seedling-sapling-
small pole stems as a residual stand.
(4) Clearcutting--harvesting a1 1 trees designated as rner-
chantable under the specified utilization standard.
All other trees on the unit were slashed and treated
as prescri bed.
Four cutting units totaling approximately 60 acres (24 ha) were harvested, one under
each of the described silvicultural prescriptions (fig. 4). Three o f the units--
those designated for clearcut, overstory removal, and understary removal--were further
sub-divided into three treatment areas for application of varying utilization and site
treatment practices. Uti 1 ization standards tested included conventional saw1 og
uti 1 ization and near-compl ete fiber uti 1 ization (table 2) ; post-harvest treatments
included broadcast burning (fig. 5) and leaving residues scattered on the site.