Operation: Clear-Cut Harvesting; Felling; Felling Process - waratah HTH624C 4X4 Operator's Manual

Harvester head

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Table Of Contents

Table of Contents

Felling

The felling stage in clear-fell harvesting influences the

whole operation.

The felling direction and stem presentation for extraction

requires careful attention, in order to reduce breakage

and to be able to present a well-delimbed stem for quick

extraction or further processing.

To reduce breakage, and provide a larger working radius,

it is preferable to fell trees against standing trees to

Felling Process

The direction of the fall is determined by the position of

the harvester head on the tree; the tree should fall in a

direct line with the tilt frame.

Position the harvester head on the tree as low as possible

while gaining the correct felling angle. Consequently, the

harvester head should be fully opened (delimb arms and

feed roller arms fully open, and the harvester head in the

tilt up position). Close the delimb arms and feed roller

arms once the selected tree is positioned in the opening.

A slight amount of pressure is then applied to the tree to

ensure the saw chain will not jam as the tree is being cut;

this will also assist with tree direction.

When the saw chain is activated, both delimb and feed

arm circuits will operate at their highest setting to ensure

the tree does not move within the harvester head while

cutting is taking place. A stream of chips leaving the saw

chain box area provides a visual indication of the cutting

taking place. Keep the saw chain activated until the tree

can be felt to move vertically. Stop the saw chain, which

automatically retracts, and apply force to the tree in the

direction of the fall.

When felling, tree control is reduced if the harvester head

is at full reach. Optimum felling is achieved using the

harvester head as close as possible to approximately

3/4 of maximum reach. During these maneuvers, the

base unit should remain firm at all times. A reduction in

reach will need to be immediately applied if the base unit

becomes unstable. Ensure the tracks are on a firm footing

at all times, avoiding locating one or both tracks on stumps

which could allow the carrier to move unexpectedly during

maneuvers.