Some notes on machinery

More common types of machinery used for harvesting are briefly presented in this section. Readers who choose to watch the images and videos suggested below are urged to keep in mind that much of the material is from manufacturers, so there may be some bias. Opinions expressed in these videos are those of the video producers, not those of FAO. Web coordinates for images and videos are found in the Cases section.


Wheeled or track mounted machines designed fell and bunch trees to be skidded, forwarded (in tree lengths), or processed. Some felling heads are capable of handling trees of up to 75 cm. There is two general types. (1) Those with a hydraulically powered articulated swivel boom that sever, lift and swing the trees to the desired direction. (2) Short wheel base machines with close coupled holding arms and shear heads, and depend on moving and swinging the entire machine to perform the bunching function, sometimes called drive to tree machines. Feller-bunchers are particularly common in North America and are increasingly used in tropical plantation forests.

Processors and harvesters

A processor is a machine that delimbs trees and crosscuts them into logs. The processor may work inside the forest or at the landing.

A harvester is a machine that fells, delimbs and cross cuts trees at the stump. Harvesters are sometimes called feller-processors.  There are wheeled as well as tracked carriages. Boom reach varies from 6 to more than 15 m, but are commonly about 10 m. Harvesters are very common in north European forestry.

Draught animals and agricultural tractors

Draught animals can and are being used instead of machines. Draught animals can be used for smaller logs from final felling operations and from thinnings in manmade forests. Feeder roads need to be more densely spaced when draught animals are used. Animals that come into question are horses, mules, oxen, water buffaloes and elephants. Horses are unsuitable in hot climate.

The farm tractor is a versatile machine that can be equipped for both skidding and forwarding purposes, and also as a base machine for processors and simple harvesters. Farm tractors are not uncommon in plantation forestry and may be entirely adequate for work in such forests.


Self propelled machines for dragging trees or logs. Skidders drag logs by mean of winch rope, chokers, grapples or clambunks. Skidders can be rubber tired or tracked. Tracked skidders are either rigid track skidders (crawler tractors/bulldozers) or flexi track skidders. Rubber-tired skidders are generally faster and less expensive than tracked skidders. They develop less traction and cannot manage as large loads as tracked skidders. Rigid track skidders are at their best with large logs and short distances. Flexible track skidders are so when distances are long, traction poor, but ground conditions not rough. Skidding is the most common method for timber extraction.


Machines that transport trees or logs by carrying them on the chassie completely off the ground. Forwarding therefore causes less soil damage than skidding. Logs/trees are typically loaded and unloaded using hydraulic or mechanical cranes. Forwarders are mainly used in planted forest and forest with not too big trees. Forwarding is not an option in selective logging of tropical high forest. Forwarders dominate extraction work in much of Europe, and are not uncommon in North America. They will probably see increased global use in plantation forestry.

Machinery for log loading  and shovel logging

Logs might be loaded on to trucks by truck mounted cranes (so called self loading trucks) or by a separate loading machine. This can be a front end loader, a wheeled or tracked machine with forks, lifts or grapples attached to lifting arms at the front end, or a hydraulic loader. Logs may also be loaded manually or by means of simple winch systems.

In shovel  logging (hoe chucking) log loaders are used to swing logs to the forest road. Rather than driving out to the log and dragging it back to the landing, the loader moves across the harvest area, grabbing logs/trees within reach, and swinging them around to drop them closer to the road until they are at roadside.

Cable yarders, spars and carriages

A cable yarder, or simply yarder or hauler, is a machine on which is mounted a system of winches that area used to convey logs from the felling area to the landing in a cable yarding system. A spar is a standing or raised tree or steel tower used to provide lift for rigging in cable yarding. A carriage is a wheeled assembly  that moves back and forth on the cable while suspended above the ground. Logs are attached to the carriage by a skidding line for yarding. 


Images and videos  


  Web coordinate
Images of feller bunchers

Videos of feller bunchers

Images of processors

Videos of processors

Video of processor at work in a cable yarding operation

Images of harvesters

Video of harvester at work

Video of horses in forestry

Video of mules in forestry

Video of oxen in forestry

Video of elephants in forestry

Video of agricultural tractors in forestry

Images of rubber tired skidders

Images of crawler tractors

Images of flexi track skidders

Videos of skidding in progress

Images of forwarders

Videos of forwarders at work in final felling

Videos of forwarders at work in thinning

Images of log loaders and shovel logging

Videos of log loading

Videos of shovel logging

Images of cable yarders

Images of spars

Images of carriages

Videos of cable yarding




last updated:  Tuesday, March 25, 2014