Publicité
Les langues disponibles
Les langues disponibles
OPERATION
WARNING: Periodically glance at the top of the tree
during the backcut to assure the tree is going to fall
in the desired direction.
WARNING: If the tree starts to fall in the wrong
direction, or if the saw gets caught or hung up during
the fall, LEAVE THE SAW AND SAVE YOURSELF!
56
• Carefully plan your sawing operation in advance.
• Clear the work area. You need a clear area all around the tree
so you can have secure footing.
• The chainsaw operator should keep on the uphill side of the
terrain as the tree is likely to roll or slide downhill after it is
felled.
• Study the natural conditions that can cause the tree to fall in a
particular direction.
Look for decay and rot. If the trunk is rotted, it can snap and fall
toward the operator.
Make sure there is enough room for the tree to fall. Maintain a
57
distance of 2-1/2 tree lengths from the nearest person or other
objects. Engine noise can drown out a warning call. Remove dirt,
stones, loose bark, nails, staples, and wire from the tree where
cuts are to be made.
1. Pick your escape route (or routes in case the intended route is
blocked). Clear the immediate area around the tree, and make
sure there are no obstructions in your planned path of retreat. Clear
path of safe retreat (Fig. 56) 45° from planned line of fall (Fig. 57).
2. Consider the force and direction of the wind, the lean and
balance of the tree, and the location of large limbs. These
things influence the direction in which the tree will fall. Do not
try to fell a tree along a line different from its natural line of fall.
3. Cut a notch (C, Fig. 58) about 1/3 the diameter of the trunk
58
in the side of the tree. Make the cuts of the notch so they
intersect at a right angle to the line of fall. This notch should
be cleaned out to leave a straight line. To keep the weight of
the wood off the saw, always make the lower cut of the notch
before the upper cut.
4. The backcut is always made level and horizontal, and at a
minimum of 2 inches (5 cm) above the horizontal cut of the notch
(D).
5. Never cut through to the notch. Always leave a band of wood
between the notch and back cut (approximately 2 inches (5
cm) or 1/10 the diameter of the tree). This is called "hinge" (E)
or "hingewood." It controls the fall of the tree and prevents
slipping or twisting or shoot-back of the tree off the stump.
59
6. On large diameter trees, stop the back cut (F, Fig. 59) before it
is deep enough for the tree to either fall or settle back on the
stump. Then insert soft wooden or plastic wedges (G, Fig. 60)
into the cut so they do not touch the chain. The wedges can
be driven in, little by little, to help jack the tree over.
7. As tree starts to fall, stop the engine and put saw down
immediately. Retreat along cleared path, but watch the action
in case something falls your way.
WARNING: Never cut through to the notch when
making a backcut. The hinge controls the fall of the
tree, this is the section of wood between the notch
and backcut.
60
en
25
Publicité
