Fell a tree with the open-notch-and-bore method
Perhaps it's not often that you must fell trees to complete a job. But a lack of practice makes it even more crucial that you know how to fell safely. The right techniques do more than help protect workers-they reduce fatigue and stress and make crews more productive.
You should focus on three key elements when work calls for felling a tree: preparation, equipment operation and the actual felling technique.
Preparation A key to proper felling is planning. Look for hazards such as hanging branches, dead or rotted trees nearby and vines that could pull a tree in a dangerousdirection. This is especially important if your crew is cleaning up an area after a rough storm (see "Weathering storm cleanup," page 34).
When choosing the direction for a tree to fall, look for obstacles or hazards such as power lines, buildings or other structures. Look for side, forward and back leans, wind direction and other work planned for the site. And always clear an escape route for exit during the procedure. Escape routes should be at 45-degree angles to the rear of the felling direction.
Proper dress is crucial. Everyone on a felling crew should take safety precautions in apparel and protective equipment, literally from head to toe. Make sure everybody on the site has a helmet and eye, face and ear protection. Also, make sure crew members have the proper gloves and leg protection. Look for chaps and pants with chain-saw-resistant fibers designed to bind a moving chain on contact and that carry a UL label.
Make sure crew members are wearing boots made for the task. Steel-toed boots with chain-saw resistance offer the best protection. And remember to have a first-aid kit on the job site.
Begin with proper equipment operation Even experienced grounds professionals must take a few moments to ensure proper chain-saw operation. This enhances safety and saves time by preventing unexpected stops or delays.
First, be sure the chain brake is engaged before starting a chain saw. Also make sure the chain catch and throttle interlock are in place and working properly.
Start the saw by balancing it on the ground and putting the tip of your boot inside the handles as you pull the cord. Keep the chain brake in place until you're ready to begin work. After use, always re-engage the chain brake before walking around.
Other key points: Never use a saw above your shoulders and head, and make sure your stance is solid before you begin any cut.
Use a safe felling method The felling process should never begin until you evaluate the tree and formulate a plan. You must understand the tree's potential hazards, its leans and the operator's escape route before you decide on the actual cutting techniques. For maximum control, many tree-care professionals opt for a felling method that incorporates a directional notch and controlling hinge.
Here are recommended steps for the notch-and-bore felling method. If you are not familiar with this method-or with felling trees in general-try to watch an experienced feller before attempting this on your own.
1. Begin with an open notch cut on the side of the tree in the direction of the planned fall (see Figure 1). Cut the notch at 70 degrees or more to allow the hinge plenty of room to guide the tree as it falls. A wide notch will not close as quickly as the tree falls, so it will guide the tree until it is close, or even parallel, to the ground. This kind of control helps reduce the chance of accidents that occur when a falling tree changes directions suddenly.
The depth of the notch should depend on the diameter of the trunk. You want a hinge that is at least 80 percent as wide as the diameter of the trunk, so cut the notch shallow enough to retain this width of hinge wood.
2. Make a bore cut through the middle of the trunk, parallel with the open notch (see Figure 2). Start at the side of the trunk several inches back from the notch you've already cut. Do not plunge the saw tip straight into the trunk. This can result in dangerous kickback. Instead, start the cut at an angle with the bottom tip, or "attack corner," of the saw and then rotate the saw until it is parallel with the open notch. Then plunge the bar through the trunk and keep it parallel to the notch cut.
Consider the tree's lean. If you can reach completely through the tree with your bar, do so starting from the side of the tree that is away from any side lean. This is the "preferred" side of the tree.
If the tree trunk is wider than the total length of your guide bar, cut half the tree from the leaning side first, and then finish the cut from the preferred side.
3. With the bar now inside the trunk, cut toward the notch to create the hinge. Your hinge thickness should be about 10 percent of the diameter of the tree (see Figure 3). For example, a 15-inch diameter trunk needs a 1.5-inch hinge.
4. With the bar still inside the trunk, cut in the other direction, toward the back of the tree (opposite the side with the notch cut). Stop cutting so that you leave about a 2-inch "strap" as your release wood (see Figure 4, below).
Now pull the saw out of the tree and engage the chain brake before getting into position for your final felling cut.
5. While standing on the preferred side of the tree, cut through the remaining release wood and move the bar of your saw from the back side of the tree toward the center until you have severed through. Engage the chain brake and, using the escape route you planned before felling, walk quickly away from the tree at a 45-degree angle to the rear of the felling direction.
Do not confuse the release wood with the hinge wood, which you should never remove until the tree is down. The hinge should break when the tree is almost to the ground. If it still holds when the tree has come down, you can remove it then.
Be careful of pressures and binds when cutting on the downed tree. That's a subject that deserves a separate article, but always be aware that hazards have not disappeared just because the tree is now on the ground.
Stability counts The benefits this method provides over other methods are significant. Using release wood helps keep the tree stable until the final cut. Also, the release wood provides support to keep the bar from getting pinched as you make your bore cut.
This method also reduces the chances of accidentally cutting all the way through the hinge before the tree begins to fall. This, in turn, reduces the chance that the tree will fall so quickly that it jumps off the stump and possibly back at crew members.
Lastly, the back-release method keeps the bar at the back of the tree during the final cut, rather than deep within the trunk. That makes it easier to walk away using your planned escape route when the tree falls.
Following these procedures allows you and your crews to fell trees safely, efficiently and with less fatigue, which further decreases the chances of an accident.
Tim Ard is a consultant for Husqvarna Forest and Garden and is president of Forest Applications training (Hiram, Ga.). Soren Eriksson of Sweden also consults with Husqvarna and has worked as a logger for many years to develop the skills he brought to the United States. Eriksson runs Soren Eriksson Training Inc.
Videos of the open-notch-and-bore technique are available through many chain-saw dealers and Forest applications Training Inc., which teaches safety and applications training programs for tree professionals. For more information, call (770) 943-4745, e-mail to firstname.lastname@example.org or consult Forest Applications' web site at www.forestapps.com.
It is important after a storm to carefully evaluate tree hazards. It is best to examine a site with a partner who can help identify dangers and "spot" fallers. When dropping a tree, fellers should keep a distance equal to double the height of the tree between themselves and any other people in the area.
Work in the direction in which the wind knocked down the trees, starting from the outside and working toward the center of the affected area.
Never climb into a pile of trees. Working from top to bottom, clear trees in this order: leaning trees and loosened root systems; broken trees; toppled trees; and then standing tree portions.
Possible overhead and ground hazards common after storms include: * Hanging limbs and dead branches * Weak and twisted trees * Broken limbs * Broken branches hanging in trees * Uprooted trees * Falling limbs, especially after ice and wind storms * Splintered trees, especially after tornadoes * Broken tops and falling debris, especially after ice storms * Blocked visibility, especially after ice and snow storms
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