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Technical Assessment of Accident Site
Starting at DP 17, EM-CAPT proceeded east along the dozer line cutting an undetermined number of hazard trees. When the crew members reached the accident site one of them proceeded to fall Tree 1. Tree 1 was 36.7” at the point of cut. The ponderosa pine, when examined, appeared to be green with no readily apparent defects that would have required it to be felled as a hazard tree.
The first step in a procedural approach to felling is to survey the tree to be felled and the felling area for any hazards. Tree 2 would have presented a considerable hazard to anyone upslope from its base.
The chainsaws EM-CAPT had with them had bar lengths of 28” and 32”; the diameter of Tree 1 at the point the cut was made was 36.7”. Regardless of which saw was used, the sawyer would have had to cut from both sides of the stump in order to complete the undercut. During this process, the sawyer experienced difficulty in obtaining a single plane, or hinge, across the diameter of the stump. This hinge is critical to the process that directs the tree into the undercut and the intended lay.
Closer inspection revealed that the sloping section of the undercut was not cleaned sufficiently as to provide a single plane across the diameter of the stump. The stump exhibits two distinct horizontal (gunning) cuts and two sloping cuts. Multiple Dutchmen that would have altered the holding wood were also present.
Due to the multiple horizontal (gunning) cuts and the multi-faceted sloping cut, it is impossible to accurately determine the exact intended lay of Tree 1; however it appears that the intended lay was to be downslope and to the left (looking downslope) of Tree 2 and 3. The sawyer made the decision that the undercut was completed sufficiently to direct Tree 1 into the intended lay, and proceeded with the backcut. As the backcut was initiated, it appears that the tree may have started to fall before the feller was able to get a sufficient amount of the holding wood cut.
As Tree 1 fell, it is possible that it contacted Tree 3, breaking it off approximately 85’ from the ground. (Statement: CRWB1 [E-10]; MOI: FAL1[F-20] )
As Tree 1 continued to fall, it is possible that it contacted the bole or a limb of Tree 2. It was this contact, or the vibration from Tree 1 hitting the ground, that caused an approximately 120’ section of the severely weakened Tree 2 to break off 16’ from the ground and fall upslope.
When this section of Tree 2 hit the ground it broke into at least five pieces. It was a section approximately 8’ long and 20” in diameter that impacted FC1 causing severe injuries.
The injury site is 35 feet from Tree 1. It is unknown what escape route the faller used and where the faller was when Tree 2 fell upslope. It is also unknown as to why FC1 was in such close proximity to the tree when it fell.
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