Innovative Harvest and Regeneration Design for Beetle Site Rehabilitation
By Tony Kryzanowski
Logging & Sawmilling Journal – February 2015
Results from test sites in Alberta show that implementing a rehabilitation design developed by the Canadian Wood Fibre Centre (CWFC) for mountain pine beetle infected stands with over 50 per cent mortality could deliver multiple benefits.
“We have been able to capture some value from these sites, tentatively reduce the pest and fire risk, and enhance stands to put them back on a productive trajectory to meet future objectives of the forest industry,” says Derek Sidders, CWFC Prairie Regional Co-ordinator and Program Manager.
With support from the Forest Resource Improvement Association of Alberta (FRIAA) Mountain Pine Beetle Rehabilitation Program, CWFC has partnered with Canfor, Spectrum Resources and University of Alberta researchers on an operational trial aimed at investigating the most effective way to recover value and rehabilitate beetle-affected small stem lodgepole pine mixed stands with over 50 per cent mortality. Forest companies avoid harvesting these sites because they have minimal conventional commercial value. However, left unchecked, they could have a significant impact on the future health and production of the commercial forest. Therefore, there is a need to develop an effective way to rehabilitate these sites.
This development project is taking place on forest blocks totaling approximately 450 hectares north of Grande Prairie. A CWFC-designed rehabilitation system, involving innovative harvesting and regeneration methods, is being deployed.
Sidders describes the harvest prescription as a full tree systematic harvesting pattern, using five metre wide parallel machine corridors centered at 20 metre intervals with landings servicing two to three machine corridors. Between each machine corridor is a 15 metre selection strip, which in total occupy about 75 per cent of the treatment area. Selection from within this area removes active attack trees, trees with commercial product potential and other stems impacting stand health and vigor.
He adds that green active-attacked, red-impacted, and green lodgepole pine trees greater than 20 centimetres in diameter or in dense patches are being recovered from the retention strips. White spruce and aspen are only being harvested from within the machine corridors and will be sorted for sawlog, OSB or biomass production.
If there are stands of dense, green, non-attacked lodgepole pine within the retention strips, the trees are spaced to about three metres between boles.
The completed area, consisting of multiple development and research test sites, will be harvested by the end of March, with site prep and planting taking place this spring and summer.
“We’ve found so far that the harvesting prescription is effective in meeting the objectives of the project and program and is reasonably easy to deploy operationally,” says Sidders.
Once operator training on the unique pattern was completed, the feller bunchers harvested down the machine corridor and back out to the landing, creating bunches from the machine corridor and selected wood from the retention strips. All bunches face the landing and are accessible from the machine corridor. Skidders backed down the machine corridors and grabbed bunches of green, red, and grey lodgepole pine, white spruce and aspen, sorting them into various decks at the landing. The material is then processed, based on the demand for the various products.
The biomass gathered from these sites is being mulched, chipped and compress-baled using a Gyro-Trac Biomass Baling System (BBS) unit, creating 700 to 1,000 kilogram bales for sale to the bioenergy or oil and gas sectors. The BBS unit is owned and operated by Hedgeco Environmental Management LTD, of Drayton Valley (see pic above).
“Throughout all these operations, time and motion studies are being completed by the CWFC, as well as very detailed time and motions studies on the biomass baler by FPInnovations,” says Sidders.
The treated sites and landing areas are being site prepped for replanting using an excavator mounted mixing or mounding attachment to create suitable micro-sites. Sites will be replanted with white spruce and lodgepole pine. CWFC and University of Alberta researchers will monitor the research sites on an ongoing basis.