- Forest managers in recent years have begun to re-examine the
possibilities of using uneven-age silvicultural systems in the
Oregon Coast Range. This increasing interest is being driven by a
variety of forest resource nianagement concerns, including wildlife
habitat diversity, visual aesthetics, and long-term sustained
yield. In an effort to begin systematic exploration of coastal
uneven-age silvicultural techniques, Oregon State University (OStJ)
researchers have established a demonstration site at Forest Peak on
OSU's Dunn Forest.
This case study involving a single treatment at a single site
reports on the design, performance, and cost of the skyline logging
operation during Septeither and October 1992 which was designed to
achieve the goals of an uneven-age management prescription prepared
by OSU silvicultural and wildlife specialists. The operation
harvested 13.9 MBF of 23-inch average dbh Douglas-fir and grand fir
The study tracked the time spent in planning and laying out
the logging system. Field and office planning and layout
procedures took 93.75 hours to conplete at a cost of $6.47/MBF.
The project also involved detailed time studies and shiftlevel
analyses of both the felling/bucking and the yarding phases
of the logging operation. A two-nan felling crew produced 6.44
MBF/Hr at a cost of $1O.44/MBF. Cutting cycle time averaged 9.22
minutes per tree, with nixnther of logs per tree, cutting method
(wedges or no wedges), percent ground slope, and base dianeter the
most influential factors affecting cutting cycle time.
The six-man yarding crew using a Thunderbird TTY5O yarder and
small Danebo MSP carriage yarded 4.7 MBF/Hr at a cost of
$58.51/MBF. Yarding cycle time averaged 5.73 minutes per turn,
with corridor yarding distance, lateral yarding distance, choker
setting method (pre-set or hot-set), and number of logs per turn
the most influential factors affecting yrding cycle time.
The six-man crew plus the hook tender averaged 1.82 hours for
each change of yarding corridors. Corridor changes involved moving
all rigging from one corridor to the next and repositioning the
yarder if necessary. The hook tender alone spent an additional
1.31 hours per corridor pre-rigging tail trees, anchors, etc.
Total logging cost including planning and layout, felling and
bucking, yarding, loading, and equipment move-in was $104.03/MBF.