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close this bookWood Harvesting with Hand Tools - An Illustrated Training Manual (ILO, 1989, 128 p.)
close this folderTREE FELLING
View the documentPREPARATION FOR TREE FELLING
View the documentTREE FELLING WITH AXE AND BOW SAW
View the documentTREE FELLING WITH AXE AND CROSS-CUT SAW
View the documentPRECAUTIONS WHEN MAKING THE UNDERCUT AND THE BACK CUT
View the documentFELLING TREES LEANING INTO THE PLANNED FELLING DIRECTION
View the documentFELLING TREES LEANING TO THE SIDE
View the documentTREE FELLING IN DENSE TROPICAL FORESTS
View the documentFELLING OF TREES WITH PLANK BUTTRESSES
View the documentWOOD WASTAGE DUE TO POOR WORKING TECHNIQUES IN FELLING

WOOD WASTAGE DUE TO POOR WORKING TECHNIQUES IN FELLING

High stumps are an indication of poor workmanship and insufficient supervision. Often they are the result of putting felling marks, which are to be left on the stump for control purposes, too high. Sometimes workers find it more comfortable to cut about 1 m above ground level (1a). Except in special cases (e.g. hollow or heavily buttressed trees), the stump should be as low as possible (1b). This helps to avoid wastage of wood and because lower stumps make skidding easier.

Where the wage level is low and the timber price high, the value of wood left in one stump (1c) may correspond to a week's wages or more of the operator.

The following table gives information on volume loss:

Stump recoverable height

Diameter cm


40

60

80

20

0.025

0.057

0.100

40

0.050

0.113

0.200

60

0.075

0.171

0.300

Considerable wood losses in felling can also occur if the tree is felled without an undercut or with an insufficient undercut (2). If the undercut is at the same level as, or higher than, the back cut, there is a risk that wood fibre will be pulled out of the butt end, reducing the value of the log.

If the undercut is too small (3a), this can be most dangerous because the tree's fall is no longer properly guided. The tree may split and this results in considerable wastage on the valuable bull end.


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A considerable amount of valuable wood is lost when large trees are felled across obstacles on the ground such as hollows (1), ridges (2), logs or rocks (3). Most species break if they hit such obstacles. Although the broken part may be small, the loss caused by cutting out the break can be considerable.

The experienced worker will look carefully for obstacles and, when determining the felling direction, he will try to avoid them. This will be possible in many cases. Remember that even heavily leaning trees can be felled to a point about 30 on either side of the lean.

Efforts to avoid obstructions not only reduce waste but also facilitate work because unnecessary cross-cutting is avoided.

The breaking of a tree can cause serious losses, especially for valuable hardwood species.


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