ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

Each of the four cutting units was sub-divided to accommodate specified post-
harvest site treatments. Residue piling, burning, and chip spreading was accom-
plished two years after harvesting was completed.
The Solo-Hemlock Study Site
The Solo-Hemlock study site is located on the Priest Lake District, Idaho
Panhandle National Forest, approximately 25 miles (40 km) northwest of Priest River.
The site represents the cedar-hemlock forest type common across northern Idaho and
parts of western Montana. Western red cedar, western hemlock, and grand fir make up
most of the stand, with western hemlock predominant. The site is on gentle terrain
at an elevation of about 4,000 feet (1220 m), and receives in excess of 50 inches
(1 27 cm) of precipitation annually. Stand volumes are typical ly high. Merchantable
sawtimber volume removed from the study site was approximately 40 Mbd-ft. per
acre (560 m3/hai, and inventory of an adjacent control area found 13,000 cubic feet
per acre (909 m /ha) of standing volume in all stems. Because the species present
are particularly subject to internal rot, volumes of residue remaining on site
following harvesting are usually high. Post-harvest residue volumes of 5,000 -
7,000 cubic feet per acre (350 - 490 m3/ha) are not unusual.
Management objectives in old-growth cedar-hemlock stands are strongly oriented
toward timber production. Major considerations include
--reducing or treating the typically heavy volumes of residue
to facilitate planting nursery stock;
--obtaining early regeneration and development of a new stand;
--avoiding adverse biological impacts on site quality and
productivity;
--avoiding or reducing insect and disease impacts.
Silvicultural alternatives depend upon the composition and condition of the
stand, and upon management objectives. Clearcutting is the most feasible alterna-
tive in older stands in which a manageable residual stand does not exist. Large
volumes of residue that remain following logging are a significant management
problem. Consequently, intensive uti 1 ization a1 ternatives are of particular interest,
and can help solve the residue treatment problem as well as recover additional usable
wood fiber.
A conventional sawlog harvesting operation, under a clearcut silvicultural
prescription, had been completed on the site just prior to initiating research.
A ground skidding logging system, using crawler tractors, had been employed. Three
treatment subunits were selected for research purposes,. Post-harvest treatments
specified for the selected subunits included simulating intensive utilization by
removal of essentially all residue; leaving residue on the site untreated; and
broadcast burning residue (the standard management practice) (table 4).