18
100647 - ChAiNSAw
OPERATiON
felling: Procedure
Small trees, up to 6 - 7 inches (15 - 18 cm) in diameter, are
usually felled in a single cut. Larger trees require a sequence of
two cutting operations: a notched undercut followed by a felling
back cut. It may also be necessary to remove buttress roots.
Step 1: Removing Buttress Roots
Buttress roots are large roots that extend above the ground and
help support the tree. If the tree has large buttress roots that
might impede the felling process, follow these steps to remove
them:
1. Make a horizontal cut into the buttress root (Fig. 10). To
prevent the guide bar from being pinched by the weight of the
wood, always make this cut first.
2. Make a vertical cut into the buttress root (Fig. 10).
3. Remove the loose section from the work area.
Step 2: making the Notched Undercut
wARNiNG
Never walk in front of a tree with a notched undercut.
This cut determines which direction the tree will fall. Always make
this cut on the side of the tree facing the direction where the tree
should fall. Make the cut at 90º to the line of fall.
1. Make a horizontal cut into the trunk of the tree (Fig. 11).
The cut should be about 1/3 the diameter of the tree and
close to the ground. To prevent the guide bar from being
pinched by the weight of the wood, always make this cut first.
2. Make a 45º cut into the trunk of the tree, above the first cut
(Fig. 11). Continue cutting until the two cuts meet.
3. Remove the loose section from the work area.
Second cut
Buttress root
First cut
Figure 10
Direction of fall
Second cut
First cut
1/3 diameter
Notched undercut
Figure 11
Step 3: making the Felling Back Cut
wARNiNG
Always recheck the area for bystanders, animals and obstacles
before making the felling back cut.
This cut fells the tree.
1. Make a horizontal cut into the opposite side of the tree from
the notched undercut (Fig. 12). Make the cut approximately 2
inches(5 cm) above the bottom of the notched undercut
(Fig. 12).
2. As the cut gets close to the notched undercut, only a thin
band of wood will support the tree. This band of wood is
referred to as the hinge (Fig. 12). The hinge helps control the
fall of the tree. Leave approximately 2 inches (5 cm) of hinge
in place. Do not cut through the hinge. Cutting through the
hinge could cause the tree to fall in any direction.
2 inches (5 cm)
Felling back cut
2 inches
(5 cm)
hinge
Figure 12
3. Periodically glance up during the felling back cut to see if
the tree is going to fall in the correct direction. If there is a
chance that the tree might not fall in the desired direction, or
if the tree might rock back and bind the chain saw, remove
the guide bar from the cut, stop the unit and use wedges to
open the cut and direct the fall (Fig. 13). Only use soft plastic
or wooden wedges. Drive the wedges into the cut slowly.
Once the wedges are in place and the cut is held open, either
carefully reinsert the guide bar and continue the cut or slowly
drive the wedges in further to push the tree over.