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Encyclopedia > Harvester (forestry)
Harvester in the Black Forest
Harvester in the Black Forest

Harvester, type of heavy vehicle employed in cut-to-length logging operations for felling, delimbing and bucking trees. A harvester is typically employed together with a forwarder that hauls the logs to a roadside landing. "Combi" machines are available which combine the felling capability of a harvester with the load-carrying capability of a forwarder, allowing a single operator and machine to fell, process and transport trees. These novel type of vehicles are only competitive in operations with short distances to the landing. Download high resolution version (1030x860, 556 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (1030x860, 556 KB) Wikipedia does not have an article with this exact name. ... A map of Germany, showing the Black Forest in red. ... Cut-to-length logging (CTL) is a system for mechanized forestry harvesting where trees are delimbed and cut to lenght directly at the stump area. ... Felling is the name given to a large area of eastern Gateshead, UK. Its name derives from the area where trees were felled to the east of town to expand and is often referred to locally as the Felling. Categories: UK geography stubs ... Delimbing is the process of removing side branches from the stem of a felled tree. ... Trees has more than one meaning: a tree, a woody plant Trees, a poem by Joyce Kilmer This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Forwarders are a type of vehicles used in cut-to-length logging operations for transporting logs to a roadside landing. ... A log is: a cut portion of a tree bole or large branch (see logging) a time-sequential data record (see data logging) logarithm a device to measure the speed of a ship This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the...

Harvesters were mainly developed in Sweden and Finland and today do practically all of the commercial felling in these countries. Harvesters work best in less difficult terrain for clearcutting areas of forest. For very steep hills or for removing individual trees, humans working with chain saws are still preferred in some countries. In the nordic countries small and very agile harvestors are used for thinning operations and manual felling is typically only used in extreme conditions or by self-employed forest owners. Alternative meaning: Chainsaw (computer program) A chainsaw (also spelled chain saw) is a portable mechanical, motorized saw. ... Thinning is in forestry a type of selective cutting primarily undertaken to make the forest more profitable in an upcoming final felling. ...

The principle aimed for in mechanised logging is "no feet on the forest floor", and the harvester and forwarder allow this to be achieved. Keeping humans inside the driving cab of the machine provides a safer and more comfortable working environment for industrial scale logging.

The leading manufacturers of harvesters are Timberjack (owned by John Deere) and Valmet (owned by Komatsu). Harvester Timberjack 1070 Timberjack, a subsidary of John Deere since 2000, is a manufacturer of forestry machinery for both cut-to-length and whole tree logging. ... John Deere For information on the John Deere manufacturing company, please see the Deere & Company article. ... Valmet Automotive is a mechanical production company in Uusikaupunki, Finland, producing cars and vehicles for other manufacturers, including: Saab Automobile (up to 2003) Saab 96 Saab 99 Saab 900 convertible Some specialized Saab 9-3 models Porsche Porsche Boxster Porsche Cayman Opel - Calibra The automobile production company was founded in... Komatsu is a city in the Ishikawa prefecture, Japan. ...

Harvesters typically are built on a robust all terrain vehicle, either wheeled or tracked. The vehicle may be articulated to provide tight turning around obstacles. A diesel engine provides power for both the vehicle and the harvesting mechanism through hydraulic drive. An extensible, articulated boom, similar to that on an excavator, reaches out from the vehicle to carry the harvester head. In fact, some commercial harvesters are adaptations of excavators with a new harvester head, while othes are purpose-built vehicles.  A group of “quad bike” all terrain vehicles The term all-terrain vehicle is used to describe a number of small open motorised buggies and tricycles designed for off_road use. ... A wheel is a circular object that together with an axle allows low friction motion, e. ... Caterpillar tracks are large (modular) tracks used on tanks, construction equipment and certain other off-road vehicles. ... The diesel engine is a type of internal combustion engine; more specifically, it is a compression ignition engine, in which the fuel is ignited by being suddenly exposed to the high temperature and pressure of a compressed gas containing oxygen (usually atmospheric air), rather than a separate source of ignition... Hydraulically powered cylinders are visible on this excavator. ... A tracked excavator by Daewoo. ...

A typical harvester head may consist of (from bottom to top, with head in vertical position)

  • a chain saw to cut the tree at its base, and also cut it to length. The saw is hydraulically powered, rather than using the 2-stroke engine of a portable version. It has a more robust chain, and a higher power output than any saw that can be carried by a human.
  • two curved delimbing knives which reach around the trunk to remove branches.
  • two gripping wheels to grasp the tree. The wheels pivot apart to allow the tree to be embraced by the harvester head, and pivot together to hug the tree tight. The wheels are driven in rotation to force the cut tree stem through the delimbing knives.
  • two more curved delimbing knives.

All of this can be controlled by one operator sitting in the cab of the vehicle. A control computer can simplify mechanical movements and can keep records of the length and diameter of trees cut. Length is computed by counting the rotations of the gripping wheels. Diameter is computed from the pivot angle of the gripping wheels when hugging the tree. Length measurement also can be used for automated cutting of the tree into predefined lengths. Alternative meaning: Chainsaw (computer program) A chainsaw (also spelled chain saw) is a portable mechanical, motorized saw. ... The two-stroke cycle of an internal combustion engine differs from the more common four-stroke cycle by having only two strokes (linear movements of the piston) instead of four, although the same four operations (intake, compression, power, exhaust) still occur. ... Computer - Wikipedia, the free encyclopedia /**/ @import /skins-1. ...

Harvesters are routinely available for cutting trees up to 900 mm in diameter, built on vehicles weighing up to 20 t, with a boom reaching up to 10 m radius. Larger, heavier vehicles do more damage to the forest floor, but a longer reach helps by allowing more trees to be harvested with fewer vehicle movements.

The first single grip harvestor head was introduced in the early eighties by Swedish company SP Maskiner.

The approximetely equivalent type of vehicle in full-tree logging systems are feller-bunchers. Categories: Stub | Forestry ...

  Results from FactBites:
w2809ea3 (2723 words)
When speaking about forestry in Finland it is good to remember that the growing season ranges between 120-180 days per year, the precipitation 550-700 mm per year, the soils are mostly rocky moraines, the target rotation period in southern Finland 70-90 years and 100-120 years in Lappland.
The harvester is equipped with a crane having a reach of 10-12 m.
Both the harvester and the forwarder are able to drive on a mat of branches and tops, which in addition to making the operation safe on soft ground, it is also an advantage from environment protection point of view.
Journal of Forest Engineering at the University of New Brunswick (3170 words)
The cost values of thinning specific harvesters, which are also capable of harvesting standard sized clear-cuttings, were referred from the publication of Ryynänen and Rönkkö [13], where the productivity and costs of different wheeled thinning harvesters were studied.
If harvester work is carried out over a period of 11 months annually with a 1 work shift arrangement, operating costs per hour are the same as the thinning harvester with 1½-work shifts.
The excavator-based harvester's cost-competitiveness comparison with the unit costs was made to the thinning harvesters, which could potentially be used for peatland thinnings but are also capable for use in clear cuttings.
  More results at FactBites »



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