Bright ideas for safely logging forests from steep slopes while going easy on the environment are emerging from the top of the South Island of New Zealand. Sources: Stuff NZ, The Marlborough Express
Two entries in the 2015 Cawthron Marlborough Environment Awards are focused on harvesting steep land forests using machinery designed and built by family-owned logging businesses in Brightwater.
PF Olsen Ltd oversaw logging at Black Birch Forest in the Awatere Valley by Cory Schroder Contracting Ltd. Kelly Logging harvested a wind-blown forest sloping towards the Branch River, off State Highway 63 between Blenheim and St Arnaud.
Both contractors used machines they built and field-tested, designed to reduce the number of workers carrying out dangerous jobs on steep slopes and damage to soils.
The Black Birch hillside on the north side of the Awatere River is exceptionally tidy for a recently logged site. However, PF Olsen Marlborough harvesting manager, Mark Wybourne said a 1-in-80-year flood during harvest of the 23-year-old forest made the job especially difficult.
“Forest harvesting is by its nature a destructive activity which can attract adverse reactions so it has been pleasing to receive positive feedback,” he said.
Trees were hand-felled then gathered into bunches using the CS Contracting Steep Slope System, an excavator tethered to a bulldozer at the top of the slope.
The machine “shovelled” logs to tracks on the hillside, tossing them downhill like an under-arm bowler. Tracks were filled back in when harvesting was finished.
Wybourne said because the harvester was secured with a cable, tracks could be built 200-300 metres apart compared with 50-60m for untethered logging.
With forestry deaths and injuries in the spotlight, another advantage of the system was that it required half the number of men and fewer machines than mainstream cable logging.
For Kelly Logging, a major challenge of harvesting 100 hectares of windblown pine off a 35 to 45-degree slope was keeping debris out of the Branch River Hydroelectric Power Scheme below.
Kelly operations manager, Tanu Malietoa, said the ClimbMAX’s ability to clear tangled wind-blown trees, particularly from gullies, reduced the risk of debris sliding into the river during storms.
Nigel Kelly of Kelly Logging has worked with Richmond engineering company Trinder and other Nelson firms to develop the ClimbMAX, with some funding help from Government.
