15
To prevent kick-back, follow these suggestions:
-Avoid cutting with the bar tip or nose, always keep a close watch
on the movement of the bar nose.
- Use caution when continuing a previously made cut.
- Start cut with saw chain in motion!
- Always sharpen saw chain correctly!
Make sure that correct and uniform height of depth gauge is
attained.
- Never cut several branches at one time! Exercise caution when
limbing - avoid contacting another branch.
- When bucking, watch out for nearby tree trunks and logs.
2. Prohibited Cutting Activities:
- Never cut under poor visibility or poor light conditions. Watch
out for slipping in slick, wet, icy and snowy conditions. Increased
danger of slipping exist when cutting freshly debarked wood.
- Never work on unstable surfaces. Watch out for obstacles in
the work area to avoid danger of stumbling. Continuously insure
secure footing.
- Never cut above shoulder height.
- Never cut while standing on a ladder. (fig.17)
- Never climb a tree with a chain saw to carry out cutting tasks.
- Do not over reach or bend over too far.
- Guide chain saw in such a way that at no time any part of your
body is within the extended cutting zone of the saw chain
(fig.18).
- Use the chain saw to cut only wood.
- Do not allow running saw chain to contact ground.
- Never use chain saw to lever and scoop away wood pieces and
other objects.
- Plunge cutting (bore cutting) and rip cutting should only be
carried out by specially trained persons due to an increased
danger of kick-back.
- Rip cuts along the length of the tree trunk should be started
only at an almost flat angle. Approach cut cautiously since the
bucking spikes cannot be applied as guides.
- Use caution when cutting split or twisted wood since torn off
wood splinters may become airborne once cut.
- The chain saw can be forced backwards against the operator
when cutting with the top of the bar (under bucking). Therefore,
it is best to cut with the bottom of the bar. (fig.19)
FELLING TECHNIQUES
Felling trees is dangerous and is a skill that must be
learned!
If you are a beginner or untrained and inexperienced,
do not attempt felling. Attend a special training
course first.
WARNING! Felling should only begin if these
requirements have been met first:
a) Only persons involved in the felling operation are in the felling
zone.
b) An emergency retreat path has been planned for all persons
involved in felling. The escape route is at 45o angle back and
away from the line of fall.
c) The nearest work station must be at a distance of two and a
half (2_) tree lengths away. Prior to felling, the line of fall must
be checked and verified that no other persons, animals, or objects
are within a range of the danger zone (measured distance is 2_
times of the tree length). (fig.20)
d) Clear base of tree of all foreign objects, under-growth, brush,
and branches. Secure solid footing to maintain solid stance. (risk
of stumbling) (fig.21)
ASSESSING THE TREE
- Direction of lean, loose or dry branches, height of the tree,
natural shape of tree, uneven growth of tree crown, rotten
tree trunk, should all be considered when assessing the tree.
- Velocity and direction of wind are important
considerations. Felling should not be done in high winds.
CUTTING BUTTRESS ROOTS: FIG. 22/-1,2,3)
- Remove largest buttress roots first. Start by cutting each
vertically, then horizontally.
Never trim rotten tree trunks before felling.
Note: The buttress root opposite the line of fall (4) should be
saved to set wedges later on.
MAKING THE FELLING NOTCH (FIG.23)
The under cut (felling notch) determines the line of fall of the
tree and acts as a guide. Cut it at a right angle in the direction of
the line of fall. Its size is about 1/3-1/5 of the trunk diameter. The
cut should be made as close to the base as possible.
EXECUTION
(Fig.23)
- Start with the upper part of the felling notch (1) (felling notch
roof)- angle cut downwards.
- Then make the lower felling notch cut (2) (felling notch base).
- Next cut horizontally and straight into the tree until it meets
exactly the upper cut forming a wedge.
- Check line of fall.
- If the felling notch requires correction, cut along its entire width.
The exception is when the tree is on a slope; then the lower
cutting angle should be increased to achieve a more open notch
with a larger wedge cut to extend fall time and increase control.
Make an upward angle cut.
- The felling cut (3) is started higher than the lower felling notch
cut (2). It must be cut exactly horizontal in front of the felling
notch, approx. 1/10 of the trunk diameter must remain as hinge
(5).
- The hinge acts as a joint. Do not cut through the hinge;
otherwise the fall of the tree is uncontrolled. Set wedges at the
proper time!
- The felling cut must only be secured with plastic or aluminum
wedges. The use of iron wedges is prohibited.
- During felling, stand sideways to the falling tree.
- When stepping back from the felling cut, watch out for falling
branches.
- When working on a slope, the chain saw operator must be
above or sideways to the tree being felled or worked on. (fig.24)
- If the tree falls, step away! Observe tree crown and wait out
the whipping of the tree crown.
- Never continue to work under tangled branches or trees.
BUCKING
SAFETY
- Position bucking spike firmly against trunk.
- Assume and maintain sure footing.
PREPARATION (fig.25)
- Clear work site of all foreign objects such as sand, stones, nails,
etc. Such objects can cause dangerous kick-back when struck.