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Full-tree Logging

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Forestry Processes

Full-tree logging is a mechanized form of logging that involves the total removal of the bole and crown of a tree. Cables or skidders are then used to transport felled trees to the roadside, crown and branches still intact, to be bucked and delimbed. Full-tree logging is primarily applicable to clearcutting and commercial thinning operations where material may be chipped and trees are short enough to be transported to the roadside.[1]

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[edit] Process

Full-tree length logging is the most widely used method of logging in the region of Canada east of Alberta, accounting for about 65 percent of the total volume harvested.[2] When trees are logged using the full-tree method, the entire above ground portion of the tree is felled. Contrary to cut-to-length logging where the bucking and delimbing are carried out at the stump inside the cutblock, in full-tree logging the entire tree, including the bole and crown, is bucked and delimbed at the roadside. A bole refers to a tree stem with a substantial thickness that can be processed into sawtimber, veneer logs, large poles, or pulpwood.[3]

[edit] Full-tree Logging: A Snapshot

An average full-tree logging operation will consist of two feller bunchers, two grapple skidders, one to two roadside delimbers, and one to two slashers or debarkers.[4] 

After the tree is felled and transported, further processing of the felled trees is carried out at the roadside or the trees are transported to a central processing yard or mill. In most full-tree logging operations, the bole is the only part of the tree that is sent to the mill.[5] A chipper is often used to chip the branches and stem of the tree at a landing site.[6] Roadside processing operations can include any of the following:

  • Full-tree chipping and hauling of chips to the mill
  • Delimbing and topping to produce tree-lengths for hauling to the mill
  • Delimbing, topping, and bucking to produce an assortment of wood to be hauled as pulpwood to pulp, paper, or panel mills, and as logs to sawmills or veneer/plywood mills
  • Chain flail-delimbing-debarking-chipping to produce clean chips for transport to pulp, paper, or wood-based panel mills[7]

Debarking of the trees usually occurs at the mill. The bark is used for boiler fuel or gets discarded as mulch. More recently, however, debarking the tree at the landing site is becoming more commonplace to produce higher quality chips since mill requirements demand chips contain less than one percent bark.[8] Chain flail debarking at the front of the chipper is the most widely practiced form of debarking at the landing site. Other types of chippers include portable drum and ring debarkers. These versions produce a lower bark content and therefore aren’t as effective as chain flail debarkers in removing bark. They also typically serve larger chipping operations that include a network of larger satellite chipping mills as opposed to chipping at a landing site.

Chipping, particularly using chain flail chippers, results in a greater amount of debris or slash comprised of tree limbs, tops, and bark at the roadside. The slash can be raked into piles and burned or left to break down naturally. A more progressive approach that assists in regeneration is to return and spread the slash and mulch back over the cutblock area.[9] A partial solution is for grapple skidders to grab a pile of the slash on the return trip to the site.[10] This involves practically no cost and is better for establishing smaller, scattered piles of slash.

[edit] Pros and Cons of Full-tree Logging

Full-tree logging has operational advantages over other forms of logging. For example, most of the slash produced is at the roadside. This reduces site preparation costs and provides greater accessibility of the cutover for replanting. Another advantage is less slash onsite may actually lead to increased soil temperature and moisture availability.[11]

One of the biggest drawbacks of full-tree logging is that it leads to a greater loss of nutrients from the harvesting site since nutrient-rich branches and foliage are removed.[12] There are also certain operational disadvantages. Full-tree logging is multi-phased and involves the use of many pieces of equipment. A buffer of up to one week's worth of wood is necessary to avoid delays caused by equipment breakdowns or traffic congestion. The estimated cost of equipment to get a full-tree logging operation off the ground is also quite high, at about $2.15 million.[13]

[edit] Equipment Used

[edit] References

  1. Cut-to-length, Tree Length or Full Tree Harvesting? Dr. Reino Pulkki. Lakehead University, Faculty of Forestry. 2008-11-05.
  2. Cut-to-length, Tree Length or Full Tree Harvesting? Dr. Reino Pulkki. Lakehead University, Faculty of Forestry. 2008-11-05.
  3. Glossary of Forestry Term in British Columbia March 2008. Ministry of Forests and Range. 2008-11-05.
  4. Cup-to-length, Tree Length or Full Tree Harvesting? Dr. Reino Pulkki. Lakehead University, Faculty of Forestry. 2008-11-05.
  5. Logging for the 21st Century: Protecting the Forest Environment. Mathew Smidt and Charles R. Blinn. University of Minnesota. 2008-11-05.
  6. A Brief Review of the Issues Surrounding Full Tree Harvesting. Northwestern Ontario Boreal Forest Management. Ontario Ministry Natural Resources. 2008-11-05.
  7. Cut-to-length, Tree Length or Full Tree Harvesting? Dr. Reino Pulkki. Lakehead University, Faculty of Forestry. 2008-11-05.
  8. Logging for the 21st Century:Protecting the Forest Environment. Mathew Smidt and Charles R. Blinn. University of Minnesota. 2008-11-05.
  9. Cut-to-Length, Tree-Length or Full Tree Harvesting? Dr.Reino Pulkii. Lakehead University, Faculty of Forestry. 2008-11-05.
  10. Logging for the 21st Century:Protecting the Forest Environment. Mathew Smidt and Charles R. Blinn. University of Minnesota. 2008-11-05.
  11. A Brief Review of the Issues Surrounding Full Tree Harvesting. Alan Wiensczyk. Ontario Ministry of Natural Resources. 2008-11-05.
  12. Cut-to-Length, Tree-Length or Full Tree Harvesting? Dr.Reino Pulkii. Lakehead University, Faculty of Forestry. 2008-11-05.
  13. Cut-to-length, Tree Length or Full Tree Harvesting? Dr. Reino Pulkki. Lakehead University, Faculty of Forestry. 2008-11-05.