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Responsible, modern forest-harvesting techniques and machinery have been designed to maximize production while supporting sustainable forest management, with little impact on the environment.

Harvesting Methods & Systems Defined
Source: Dr. Reino Pulkki, R.P.F.
Lakehead University, Faculty of Forestry

| CUT-TO-LENGTH, TREE-LENGTH OR FULL TREE HARVESTING? |


Feller HARVESTING METHOD

The form in which wood is delivered to the logging access road, and depends on the amount of processing (e.g., delimbing, bucking, barking, chipping) which occurs in the cutover.

The different harvesting methods are:

Cut-to-length (shortwood)

  • trees are felled (cut-off above the stump with stump height less than one-half stem butt diameter), delimbed and bucked to various assortments (pulpwood, sawlog, veneer bolt, etc.) directly in the stump area
  • trees can be topped down to, for example, a 5 to 10 cm top diameter, and limbs and tops can be left in windrows or spread over the cutover
  • logging can be fully mechanized (use equipment), motor-manual (use motorized hand tools) or manual (use hand tools - e.g., axe, cross-cut saw, barking knife)
  • off road transport is usually by forwarding (i.e., wood carried off the ground), although cable skidders are sometimes used
  • the cut-to-length method can be utilized in all silvicultural systems or interventions (e.g., clearcutting, partial cutting, thinning, individual tree selection cutting)
  • roadside landings are minimal since all processing is done in the cutover and high roadside log piles can be made
  • the method also allows for better sorting and storage of various wood assortments. The method can be used efficiently even when in-woods inventory levels are minimal (i.e., hot-logging is very applicable)
  • this method is re-establishing itself in North America due to its "softer" environmental impact
  • it now accounts for about 20% of the volume harvested in Canada east of Alberta.

Tree-length
  • trees are felled, delimbed and topped in the cutover
  • delimbing and topping can occur in the stump area or at a point before roadside
  • in softwoods, trees are usually topped at a 7-10 cm top diameter
  • trees are usually skidded (i.e., part of the load dragged along the ground) with cable or grapple skidders
  • crawler tractors and clam-bunk skidders are also used to some extent
  • the tree-lengths can be bucked or slashed (i.e., mechanical bucking) into pulpwood and logs at roadside, or hauled as tree-lengths to the point of utilization (e.g., sawmill, pulpmill, paper mill, veneer plant, or central merchandizing yard)
  • the tree-length method is most applicable to clear cutting, but can be used in row thinning and partial cutting
  • landing requirements at roadside are much greater that for the cut-to-length method
  • the tree-length method accounts for about 15% of the volume harvested in Canada east of Alberta.

Full tree
  • trees are felled and transported to roadside with branches and top intact
  • transport to roadside is mainly by cable, grapple or clam-bunk skidders
  • the full trees are processed at roadside or hauled as full trees to a central processing yard or the mill
  • roadside processing of full trees can include:
    • full tree chipping and hauling of full tree chips to the mill
    • delimbing and topping to produced tree-lengths for hauling to the mill
    • delimbing, topping and bucking to produce wood assortments for hauling as pulpwood to pulp, paper or wood-based panel mills, and logs to sawmills or veneer/plywood plants
    • chain flail-delimbing-debarking-chipping to produce clean chips for transport to pulp, paper or wood-based panel mills
  • with the full tree method the limbs, tops and wood residue, and in the case of the chain flail-delimber-debarker-chippers also the bark, are left in piles at roadside and must be disposed of.
  • the slash (i.e., logging residues) can be raked into piles and burned, or left as is for natural breakdown
  • another alternative is to spread the slash or delimber-debarker mulch back into the cutover
  • the full tree method is most applicable to clearfelling operations, and in some cases to first commercial thinnings where the material is chipped directly in the stand or short enough to be forwarded to roadside
  • the full tree method is also be applied to partial cutting, but special care taken and special cutting patterns used to ensure damage to residual trees is minimized. Otherwise >20% of residuals can be damaged
  • the landing requirement is the the highest with this method
  • the full tree method is currently the most widely used logging method in Canada east of Alberta, and accounts for about 65% of the volume harvested

Whole tree
  • there is much confusion in the use of this term. For example, in the U.S., the term whole tree logging is equated to full tree logging
  • in this course a broader definition of the whole tree method is used, where full trees including most of the stump are removed to roadside for processing and utilization
  • this method is seldom used in Canada

Complete Tree
  • full trees, include stump and major roots are removed to roadside for processing and utilization
  • this method is seldom used.


HARVESTING SYSTEM
  • the tools equipment and machines used to harvest an area. The individual components of the system can be changed without changing the harvesting method (i.e., the form in which wood is delivered to roadside in)
  • a typical cut-to-length logging system could employ a one-grip harvester which fells, delimbs and bucks the trees right in the stump area, and a forwarder to carry the wood assortments to roadside
  • a common tree-length system includes motor-manual cutting (i.e., felling, delimbing and topping with the aid of a chain saw), tree-length skidding to roadside with a cable skidder, and slashing at roadside
  • a typical full tree harvesting system could include a feller buncher, grapple skidder, stroke delimber and slasher.

Some Equipment used in Modern Logging

To view more information on this topic, visit Forest Harvesting Home Page by Dr. Reino Pulkki, R.P.F., Lakehead University, Faculty of Forestry


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