3 minute read
SAW SHOP: BREAKING DOWN THE FELLING PROCESS
By Bryan Wagner Chainsaw & Logging Safety Trainer, FMIC
I have written several articles dealing with the manual felling process. Manual felling is the most significant risk in our industry. Twenty-five years later, mechanical felling has increased dramatically. We now have equipment that can harvest timber on steep terrain or in the wet areas of a swamp. Our industry has done a great job of trying to reduce risk and exposure by using mechanical means. With that being said, there are still situations that require timber to be felled with a power saw. So, we still have significant risk present on some days. Several articles over the years have dealt with the 5-part felling plan and I thought I would cover it again.
THE 5-PART FELLING PLAN
deals with specific risk and exposure present during all phases of the manual felling process. Let’s do a quick review of the felling plan.
1: LOOK
• Check for ALL overhead hazards. We have a fresh crop of leaves, really LOOK!
2: CHECK SIDE-LEAN
• Check the side-lean of the tree. The weighted side of the tree is the Bad-Side. Avoid or limit your time on the Bad-Side!! If you are not there, you are not injured there!
3: ESCAPE!
• Your escape route is a 45-degree angle away from the falling stem. Get out of Dodge!
4: HINGE THICKNESS.
• Your “basic” hinge thickness should be 1/10th the DBH of the tree. Hinge thickness will vary by the fiber type of the tree species.
5: BACK-CUT PLAN.
The final felling cut. I recommend a “controlled-release” back-cut. • The tree doesn’t move until I tell it to move!
After reviewing the felling plan, we will move forward. I am going to break down the manual process into sections. In this issue, we will discuss the face notch. Future articles will cover the hinge, the escape route, and finally, the back-cut plan.
I am looking forward to explaining each critical section of the felling process.
THE FACE NOTCH
EXAMPLE OF THREE COMMON NOTCH PATTERNS Top: Humbolt Undercut Middle: Conventional Face Cut Bottom: Open Face Notch
After visually assessing and completing your felling plan, notching the tree is the first physical step in the felling process. An improper notch can start a series of events that can become catastrophic, sometimes leading to injury or worse.
- Use your felling plan, constantly Look-Up!
- Both cuts of the notch Must Meet!! No By-Pass!!
- Notch depth should be 80% of the diameter of the tree.
- Notch angle should control the falling stem 70-90% of its fall.
- LOOK-UP AGAIN!!
A cut behind or under a face notch is called a “By-Pass” and is considered a serious safety violation. By-pass is serious because it misplaces where proper hinge wood belongs. By-pass behind the face notch sets the hinge back and away from the notch opening. This mistake creates severe pressure as the tree falls to the ground. Often, pulled fiber or split butt logs result from this type of by-pass. Barber Chaired trees have taken many lives in our industry.
By-pass can also happen by “missing low” or under-cutting where the hinge needs to be. No Hinge - No Control! The simple fix to bypass, Make Both Cuts Meet!!
Your notch angle controls how long the hinge is going to control the falling tree. The “open-face” system tries to set a 70-90-degree notch opening. The theory behind the open-face system is by the time the tree has reached 70-90 % of its fall, the energy to “rebound” has been spent. This reduces the chance that the tree will rebound, maybe hurting one of my guys.
BOTH CUTS OF THE NOTCH MUST MEET!!
Notch depth should include 80 % of the stump diameter. What you are doing is setting the hinge length, more length, more strength, more control. A note of caution here, watch for root fiber. This fiber lacks the strength that “good wood’ has. I try to set the notch behind the root flares.
Your notch angle controls how long the hinge is going to control the falling tree. The “open-face” system tries to set a 70-90-degree notch opening. The theory behind the open-face system is by the time the tree has reached 70-90 % of its fall, the energy to “rebound” has been spent. This reduces the chance that the tree will rebound, maybe hurting one of my guys.
No Hinge - No Control! The simple fix to by-pass, Make Both Cuts Meet!!
