Wood harvesting operations

Felling is the process of downing individual trees, an element of the task of logging.In hand felling, an axe, saw, or chainsaw is used to drop a tree, followed up by limbing, bucking, and in traditional applications hewing. In the modern commercial logging industry, felling is typically followed by limbing and skidding.

Limbing (also known as “chasing”) in logging is the process of removing branches from the stem of a felled tree. Options for cutting off the branches include chain saws, harvesters, stroke delimbers and others. Limbing can happen at the stump in log/tree length systems and cut-to-length systems or at the landing in whole-tree logging.

When the tree is lying on the ground, branches may be storing enormous potential energy through mechanical strain. When a branch is cut, often with a chain saw, this energy can be released suddenly and the branch can jump dangerously. In addition, a branch may be supporting the tree, and the tree can fall or roll when the branch is cut. For these reasons, delimbing is a skilled operation requiring careful safety planning.

In British English, limbing can be synonymous with snedding. Alternatively, limbing can be used to describe the operation on larger branches, and snedding on smaller.Snedding is the process of stripping the side shoots and buds from the length of a branch or shoot, usually of a tree or woody shrub. Most commonly this process is performed during hedge laying.The verb, “to sned”, analogous to today’s limbing, was also used by woodcutters in Scotland to refer to the process of removing branches from felled trees. Whether using an axe or a chainsaw the relative difficulty of snedding was a key measure of the difficulty of the job as a whole.

Log bucking. Bucking is the process of cutting a felled and delimbed tree into logs. This can be a complicated process because logs destined for plywood, lumber, and pulp, each have their own price and specifications for length, diameter, and defects.Bucking may be done in a variety of ways depending on the logging operation. Trees that have been previously felled and moved to a landing with a log skidder are spread out for processing. While many of the limbs have broken off during transport, the remaining limbs and stubs have to be trimmed. The bucker will anchor the end of an auto rewinding tape measure which is attached to his belt and walk down the log trimming as he goes. The tape is anchored gently with a bent horseshoe nail in the bark so it can be jerked loose when the measurement is completed. When a suitable place to buck the tree is located the cut is made. Local market conditions will determine the particular lengths cut. It is common for log buyers to issue purchase orders for the length, diameter, grade, and species that they prefer and will accept. There are often different prices for different items. The bucker is the one who turns a tree into logs, and to do his job properly must cut the tree for optimum value.

Hewing is the process of converting sections of a tree stem from its rounded natural form into a form with more or less flat surfaces using primarily, among other tools, an axe or axes. It is used as a method of squaring up beams for building construction.One can hew wood by standing a log across two other smaller logs, and stabilizing it either by notching the support logs, or using a ‘timber dog’ (a long bar of iron with a tooth on either end that jams into the logs and prevents movement). The hewer marks a line along the length of a log, usually with a chalk line, then chops notches to a short distance (10 mm for example) from this line into the log every foot or two using a chopping or scoring axe. The hewing can be done on the sides with a broadaxe by standing over or to the side of the log and chipping off the sections of wood in between the notches. This results in a rough surface pared down just shy of the marked line. The notches remove a fair amount of wood, make chipping easier and prevent long shreds of material being removed, only smaller chips. Hewing occurs from the bottom of the stem upwards towards what was the top of the standing tree, reducing the tendency of the broken fibers to migrate inwards towards the eventual beam.

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1. What wood harvesting operations do you know?

2. What instruments are used in hand felling?

3. How is limbing called in British English?

4. How may bucking be done?

5. What process is called log hewing?