A report has been released about a tree felling accident that occurred in Idaho on the Caribou-Targhee National Forest July 31, 2012. You can read the entire report, but briefly, a Lodgepole pine being felled was 18 to 24 inches in diameter and leaning toward an open area where the chain saw operator hoped it would land. When the back cut was complete the tree did not fall since the weight of the limbs was pulling it 90° off the desired direction of fall toward a pump house with solar panels on the roof. The sawyer continued cutting, going all the way through the holding wood. At that point, the weight of the limbs pulled the tree toward the pump house where it landed, crushing some of the solar panels.
The report identified several things that went well. In addition, here are the lessons learned:
- “Tree felling is a dynamic situation. Each tree needs to be sized up and a planned procedural approach needs to be in place. Using a different cutting procedure may be needed even on similar trees.
- Reviewing the situation with the sawyer, discussion included multiple cutting procedures ( ¼ cutting the back cut so wedges will be in the tree early and often).
- Always check your cuts.
- Don’t cut your holding wood.
- Use wedges.
- There were two other certified sawyers available that could have gone with him to act as spotters and/or give advice.
- The Recreation Tech. could have easily walked to the area and discussed the project with him.
- Perhaps take a bit more time for the entire operation as there were costly infrastructures involved in the falling area.
- Sawyer spent some time after the incident re-checking and reviewing his skills with a C sawyer and felled trees as planned. He feels it is a “lessons remembered” experience, as there are lots of little things to learn in the beginning which can sometimes be taken for granted.”
The issue is not over. These solar panels are still generating electricity when the sun is shining. There is a big possibility for electrocution when the tree is removed if the live cables are touched. Each panel can generate 40Vdc and if 4 panels are in series , this will be 160VDC !!
re: “…( ¼ cutting the back cut so wedges will be in the tree early and often).”
There’s ample room in a tree that size to start a wedge behind the bar early without quarter-cutting the backcut. How can someone be expected to line up quarter cuts, if they lack the control to not cut through the hinge?
As an arborist accustomed to falling trees around structures, I would add you can always place a suitable rope in the top of the tree to aid in counterbalancing the lean if there is room to fall the tree in one piece. Or limb and chunk the tree from the top down which takes more time and requires skill using spurs.
Of course, I am not a USFS certified faller who only works on the ground. But the notion that he did not use wedges kinda boggles the mind.