Tips from the experts
Industry experts offered many useful tips on improving log quality at recent workshops held in British Columbia and Alberta.
By Jim Stirling
Commitment and communication sound like words a politician might use. The two "C" words are, however, key ingredients in the drive to improve log quality.
They are necessary to ensure everyone
involved-from those marketing lumber to the loggers in the bush-are on the
same technology transfer page.
The workshops, held in Grande Prairie,
Alberta and Kelowna and Prince George, British Columbia, were hosted by
the western division of the Forest Engineering Research Institute of
Canada (FERIC), in co-ordination with the Forestry Continuing Studies
Network. FERIC is taking more of its practical workshops into the regions
to spread the message closer to the action. In this case, logging
contractors, operators and front line supervisors. The approach proved
successful with the workshops attracting more than 300 people.
Inaccurate log lengths compromise
recovery, value, yield and volume. "The cut-off saw is the place
where the job loggers do has the biggest impact on the sawmill,"
explains Goudie. A bad bucking decision can't be reversed. The
multi-combination of log lengths, especially with the lower ranked bucking
solutions, can be the difference between profit and loss for a sawmill, he
On a different tack, Bob Harrison
describes a good log as one that meets or exceeds the standards set by the
consuming mill. Harrison is in a good position to know, being the retired
woodlands manager for Riverside Forest Products in Kelowna. He, too,
emphasizes that delivering log lengths within the specified tolerances is
important to the mill, allowing it to maximize lumber recovery and grade
Explaining the ways in which machines
damage logs, he pointed to lifting before the cut is completed at the
felling stage, during bucking and by dull saw use.
Andersson explains there are
non-controllable and controllable factors at play. The former category
includes stand, tree characteristics, species, the upper and lower parts
of the stem and to a lesser degree weather and seasons. Controllable
factors include varying standards between companies (from plus or minus
2.5 centimetre tolerances to 7.5 centimetres); computer settings and
calibration; knowledge of measuring system; condition of equipment; and
commitment to log measuring accuracy.
Communication of required log
specifications, either metric or Imperial (don't try converting), and
Knowledge of the system for operators and
supervisors so they can access, modify and troubleshoot.
That point was also touched upon by Dave Blackmore from Denharco who notes technology continues to change rapidly and the more complex it becomes, the less productive systems can be. Blackmore provided a detailed breakdown of log measuring systems and their accompanying components. He says most errors relate to how systems are managed. And he had some sound advice for contractors buying measuring systems; "Go to the manufacturers, dig in their brains about what the machines can actually do."
Ismo Makkonen listed systemic and
occasional sources of length and diameter log measuring errors. The senior
researcher from FERIC's Montreal office passed on some useful tips to
contractors. He notes larger measuring wheels with longer trailing arms
tend to make smaller errors. He also recommends keeping them in good shape
with no loose bearings and free of sap and dirt. And when it comes to
measuring log diameters, two delimbing knives are more accurate.
Not surprisingly, considerably more
breakage occurs to logs sitting around a mill yard for a year than in
fresh wood. Log damage during saw type feller bunching can be due to stem
tension during the cut and in accumulating smaller stems; making
incomplete cuts; using dull cutting teeth and more than optimum saw speed
during the cut.
This page and all contents
©1996-2007 Logging and Sawmilling
Journal (L&S J) and TimberWest Journal.
last modified on Thursday, October 07, 2004