Also known as preparing timber, logging involves the process of felling, trimming and transporting trees. Most trees that are logged are strong and sturdy and require a great amount of physical strength to cut down. To ease the efforts involved in logging, manufacturers make various types of logging equipment.
Feller bunchers help clear groves of trees. The same machine then stacks the felled trees onto skidders for transportation. Feller bunchers, when used to cut smaller trees, use hydraulic shears. Larger trees are cut using rotary saws or chainsaw blades. Feller bunchers have two chassis designs. The light-to-medium machine has a tractor chassis with rubber tires, while the heavy-duty machine has a tracked design similar to a bulldozer. A hydraulically controlled clamp helps hold the tree while the blades are cutting through it. Feller bunchers can only be used by skilled operators.
Most of the trees felled from the forest easily measure 30 to 40 feet in length and weigh a couple of tons, making them impossible for humans to lift them. Log loaders assist in lifting and stacking the logs. The log loaders have a cable grapple, which is a pair of jaws suspended from two cables. The grapple is connected to a clutch lever and a brake pedal that can be handled by the operator. Some models also have a tag line to help the grapple rotate. The grapple can be opened like a mouth and dropped over the log and lifted with the grapple jaws closed around the log. The logs get lifted and then stacked one on top of the other on log trucks for transportation.
These machines are basically used to lift logs that are thousands of feet away. As the logs come close to the machine, they can be swung sideways and made to lie on their sides, which gives the machine its name. The equipment has a leaning tower from which cables hang downwards. These are called chokers and hook on to the logs. The cables are taken around the logs and fastened in a slipknot fashion. This is the simplest method, which uses only two cables. Other complex configurations have three or more lines. The logs are placed in the landing area from where the log loaders lift and stack them as required.