Text from
the OSHA Logging Standard Amendment issued September 8, 1995 in the Federal RegisterParagraph
(h)(2)(vii) -- Backcuts
The final rule requires that backcuts be placed above the horizontal face cut in all
felling except tree pulling operations. OSHA was requested to clarify whether the
requirement in paragraph (h)(2)(vii) applies to Humboldt cutting and open face felling.
OSHA stayed for six months the backcut requirement in paragraph (h)(2)(vii) as it applied
to felling trees using the Humboldt cutting method. OSHA also explained that it would use
the six months to further clarify the backcut requirement as it applies to both cutting
methods.
Open face felling. After OSHA published the final rule, the Agency was requested to
clarify whether the backcut requirement applied to open face felling. In brief, the
backcut requirement does not apply to open face felling, and OSHA is clarifying the final
rule and compliance directive accordingly.
In open face felling, two facecuts are made diagonally into the stem so there is no
horizontal face cut. The backcut requirement applies only where a horizontal face cut has
been made. Where a horizontal face cut is used, there is a greater potential that the
notch (or wedge) is not as open or that very little or no hinge wood will be left if the
backcut is made at the same level. This may result in the tree kicking back or falling in
the wrong direction.
In open face felling, the notch is much more open than in conventional felling. As
such, there is little or no danger that placing the backcut at the level of the notch will
result in the notch closing (i.e., the falling tree hitting the stump) too soon and the
tree kicking back off the stump. This is because the openness of the notch permits the
tree to fall in the intended direction for a greater interval before the notch closes and
the hinge breaks. Either the tree is on the ground or almost parallel to the ground, and
thus committed to falling in the intended direction, before the hinge breaks. In addition,
there is little danger that no hinge wood will be left to help direct the falling of the
tree.
Humboldt cutting. In the Humboldt cutting method a horizontal cut is made into the face
of the tree and a notch is cut below the horizontal cut at an angle. By contrast, in
conventional felling, the notch is cut at a diagonal above the horizontal face cut.
In several regions the Humboldt cutting method has replaced the conventional method.
The Humboldt cutting method is heavily used in the western States and is also used on high
quality trees, such as veneer logs and redwoods. Loggers have switched from the
conventional to the Humboldt method primarily for productivity reasons. In Humboldt
cutting, the notch is made into the stump rather than the log (Ex. 9-15). Thus, if
properly done, the cutting of the notch does not result in the loss of usable wood. OSHA
is aware that some fellers who use the Humboldt cutting method prefer to make the backcut
at the level of the horizontal face cut, but the record indicates their preference is due
to these production rather than safety reasons (Ex. 9-15). Some contractors and mills want
log butts to be smooth. By placing the backcut at the same level as the face cut, these
loggers do not have to make an additional cut after the tree is felled in order to smooth
out the log butt. In some cases, to make the additional cut might require walking down a
hill where the felled tree has rolled or the additional cut might have to be made by the
employee bucking the tree.
In logging operations where the Humboldt method is most heavily used, fellers most
often only cut a notch that is no greater than 45 degrees, making the openness of the
notch similar to that of conventional felling. Fellers do this in order to keep the stump
as short as possible and thereby reduce the lost of usable wood. At 45 degrees, the face
notch alone does not fully address both the hazards of misdirected falling and kickback.
Proper backcuts that provide sufficient hinge wood are critical. Sufficient hinge wood
helps to hold the tree to the stump during most of its fall and thereby allows the hinge
to steer the falling tree in the right direction. If the hinge is inadequate or if
pressure is placed on the hinge, it will break too soon and the tree will be left without
a steering mechanism. Without the hinge wood, the tree may twist and bend, and fall in the
wrong direction. (OSHA is revising paragraph (h)(2)(vi) to expressly state that this
requirement is intended to address the hazard of misdirected falling.) Placing the backcut
above the horizontal face cut is also necessary to provide a platform to block the tree
from kicking back once the hinge does break. Where there is a potential that the face
notch will close before the tree hits the ground, which is the case with most cutting
using the conventional and Humboldt methods, this platform is necessary to prevent
kickback. Where the backcut is at the same level as the horizontal cut, there is no
platform to block the backward movement of the tree should kickback start to occur. (OSHA
is revising paragraph (h)(2)(vii) to expressly state that this requirement is intended to
address the hazard of tree kickback.) In both, misdirected falling and kickback, the
feller or other team member could be hit by the tree. The risks of such injury are further
increased if other conditions are present, such as wind, sloping terrain, or tree lean.
To address these risks, most State logging safety rules require that backcuts be above
the face cut in all felling, including Humboldt cutting. For example, in Oregon, a
State-plan State, the backcut requirement applies to any tree with an 8-inch or larger
diameter base height. Only the State of Montana, which has advisory criteria, permits the
backcut to be level with the face cut in Humboldt cutting.
After reviewing the record in this rulemaking, OSHA reaffirms that the record supports
the necessity of applying the backcut requirement specified in paragraph (h)(2)(vii) to
Humboldt cutting (Ex. 2-1, 4-61, 4-64, 26A; 59 FR 51675). The record clearly shows that
manual felling is the single most dangerous occupation in logging. The BLS Census of Fatal
Occupational Injuries indicates that more than one-half of all logging employees killed in
1992 were felling trees at the time of their accident (59 FR 51675). In addition, the WIR
survey indicated that almost one quarter of all employees reporting injuries were felling
trees at the time they were injured, and that the most frequently reported cause of their
injuries was being hit by a tree (Ex. 2-1). The record also shows that tree kickback and
misdirected falling are two of the major reasons why employees are hit by falling trees.
For example, the record contains many reports of employee injuries and deaths due to
misdirected falling and tree kickback (Ex. 4-61, 4-64, 26A).(10)
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Footnote(10) It has been argued by some parties that placing the backcut above the
horizontal face cut is only necessary in selective cutting operations, and not in clear
cut operations. The reason they give is that in clear cut felling trees are felled into
the downhill side of the slope and there is no danger the tree will kick back or fall
against gravity in the wrong direction. However, the injury data in the rulemaking record
do not support this position. According to the WIR survey, 62 percent of all injuries
reported occurred in clear cut operations.
Proper backcuts where adequate hinge wood and a platform are left will reduce the
potential for such injuries (Ex. 4-5, 21D, 22, 38I). In fact, manual felling training
materials entered into the record instruct fellers, for safety reasons, to place the
backcut above the horizontal face cut (Ex. 4-5, 4-6, 4-10, 4-19, 4-169, 4-173, 5-1, 5-29,
8-18, 21, 29). Moreover, the record demonstrates that the primary reason that fellers
prefer to place backcuts at the same level as the face cut is not because of safety, but
rather because they do not want to have to make an additional cut to trim the log butt.
However, there is no evidence in the record which indicates that making an additional cut
would have any significant impact on productivity.
The purposes of this standard are best realized by requiring that the backcut provide
sufficient hinge wood to direct the fall of the tree, and that the backcut be above the
horizontal face cut so a platform is formed. These safe manual felling practices will help
to ensure the tree falls in the intended direction and does not kick back off the stump
when the notch closes. OSHA is revising the final rule and compliance directive to more
clearly reflect OSHA's intent that these work practices be followed.(11)
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Footnote(11) OSHA notes that one safe technique for making the backcut is to start the
backcut with a plunge cut/bore cut to establish the hinge. The backcut should then be
moved toward the back of the tree. This backcut method provides for two holding points
until the tree is finally released. This backcutting method will prevent the tree from
releasing too soon or moving before the feller has moved to a point of safety. The record
shows that this backcutting method is a safe technique for felling (Ex. 9-20), and OSHA
suggests this technique when conditions such as, but not limited to, tree lean, slope, and
large tree size indicate that felling the particular tree may present additional hazards.
OSHA has not specified in the final rule how far above the face cut the backcut must be
placed. By contrast, the Washington and Michigan logging standards require that the
backcut be approximately 2 inches above the face cut to provide adequate hinge wood. On
the other hand, the Oregon logging rule does not specify a minimum vertical distance. OSHA
believes that a backcut placed at least one inch above the face cut should provide an
adequate platform to prevent kickback and to allow the hinge to help steer the falling of
the tree in the intended direction. OSHA believes that a one-inch platform would provide
an adequate margin of safety for the feller while still providing the contractor with a
fairly square-end log.(12)
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Footnote(12) OSHA's decision to require that backcuts in Humboldt cutting be above the
horizontal face is based in part on the fact that most loggers currently using this method
are making the notch the same size as in conventional felling -- 45 degrees. A 45-degree
notch is generally not open enough to control for both misdirected falling and kickback
hazards. However, where a notch of 70 degrees or greater is cut, the notch in Humboldt
cutting acts as it does in open face felling. As discussed above, in open face felling,
because of the 70- to 90-degree notch, it is unlikely that the tree will fall in the wrong
direction or kick back. OSHA stresses that this is due to the openness of the notch rather
than the type of cutting method being employed. As such, OSHA is clarifying the compliance
directive to indicate that where the notch is at least 70 degrees, it is not as critical
that the backcut be above the horizontal face cut or the notch of the face cut, regardless
of whether the open face or Humboldt method is being used.
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