Chain saws are the perfect tool for cutting up fallen trees and large branches. But figuring out where to start and how to go about the job safely is a challenge. We enlisted a chain saw expert to walk us through the process of cutting up a large fallen tree.
We'll show you what we learned, including techniques for removing branches and cutting up the trunk. Of course, safety is the most important consideration when you're using a chain saw. See “Safety Tips” for key precautions I've taken to heart. But in addition to these tips, be sure to read and follow the safety precautions listed in your chain saw owner's manual.
Cutting with the chain on the bottom of the bar is the most common and natural-feeling way to cut. The saw pulls slightly and is easy to control by maintaining a firm grip. Cutting from the underside of a branch requires you to cut with the top of the bar. This is a little unnerving at first because the saw pushes toward you. But it's safe as long as you're well braced and follow all other precautions.
However, there's one spot on the bar that you should carefully avoid. This spot, called the kickback zone, is the top half of the bar's tip. If the kickback zone comes in contact with something while the chain is moving, the saw will kick up and back toward you. That's why modern chain saws are equipped with a chain brake designed to stop the chain if a kickback occurs.
The most common chain saw injuries to the thigh and left arm can be virtually eliminated with just a few simple precautions. First, always wrap the thumb of your left hand around the front handle while you're cutting. This encircling grip keeps the saw under control in the event of a kickback.
Second, when you move from place to place with the saw running, even if it's only to the next branch, always remove your right hand from the back handle and carry the saw at your side with your left hand holding the front handle. Then if you trip or stumble, there's no way the saw's engine can accelerate and start the chain spinning.
Put on your safety gear
Buy safety gear and wear it. Special chaps will often stop a moving chain and save your thigh. A helmet with a face screen and ear protection is a convenient way to keep head, eye and ear protection handy in one comfortable package. Wear steel-toed, cut-resistant boots and a long-sleeved shirt to protect against the inevitable scratches. You'll find this gear at chain saw dealers.
Now that you're dressed, fill the saw with gas that's premixed with two-cycle oil (see your owner's manual for the proper mix for your chain saw). Then fill the oil tank with bar and chain oil. After the saw is filled, move it at least 10 ft. away from the filling area to a spot cleared of any ignitable debris.
To start the saw, engage the chain brake, turn on the ignition switch, pull out the choke (for a cold engine) and lock on the fast idle. With the saw sitting on the ground, put the toe of your right boot into the back handle loop and grasp the front handle with a stiff left arm. Pull the starter handle to fire up the engine. Push in the choke and take it off fast idle, then pull the chain brake back toward the front handle to release the chain brake for cutting.
Get a feel for how your saw responds to the throttle. Cut only when you are in a comfortable, well-balanced position with your feet about shoulder-width apart. Stand to one side of the saw, never directly behind it.
You'll feel different forces when cutting. When cutting with the bottom of the bar, the saw will pull you into the work. When cutting with the top of the bar (undercutting), the saw will tend to push you away from the work. This second force is called a pushing chain. When cutting with a pushing chain, brace the back handle of the saw or your arm against your thigh to gain more control of the saw and reduce fatigue.
Adjusting chain tension
Before starting, check the chain tension. Recheck it after every hour or so of use, and adjust it if necessary. New chains stretch and need to be checked after 20 minutes of use. Loose chains can fly off the bar, causing serious injury. A loose chain also damages the drivers BAR on the chain and prevents them from fitting back into the bar groove.
To make adjustments, loosen the bar nuts that hold the bar. Then lift the bar while tightening the adjusting screw until the chain is snug against the bar. The tension is correct when you can't lift the chain drivers free of the bar groove but you can still drag the chain easily around the bar with a gloved hand. Retighten the bar nuts.
Before you even start your saw, stand back and size up the situation. Think about how you'll cut each branch and what will happen when you do. Obviously branches facing up will fall.
Make sure the fall path is open. It's not so clear what will happen when you cut branches trapped under the fallen tree. They'll be under pressure, and in some cases removing them will cause the tree to drop. Even seasoned pros can't always predict how far the trunk will drop, or whether the tree will roll.
But you should always imagine the worst-case scenario and be prepared for it. Take a few minutes to clear a path behind you and to the side for a quick retreat. And always work with a partner so that if you become trapped or injured, you'll have someone to call for help.
Start by removing branches closest to the lower end of the trunk, and work toward the top of the tree. Whenever possible, stand on the uphill side of the tree. Photos 1 – 3 show techniques for removing branches from the top side of the trunk and branches under pressure.
Work from the left side of the trunk (as you face toward the top of the tree). This allows the safest and most efficient use of the chain saw because you can rest the side or bottom of the saw on the trunk and slice off the branches with a pivoting motion (Photo 1).
As you cut branches out from under the trunk, it will settle to the ground. Finally the trunk will either rest entirely on the ground or hang suspended. If it's suspended, cut the trunk loose from the stump and carefully roll it to the ground. If you try to cut straight down through a trunk that's supported on both ends, the weight of the trunk will pinch the bar and stop the saw. Instead use the technique shown in Photos 4 and 5 to avoid binding.
The saw can also become pinched if you cut too far through a branch that supports the trunk. If this happens, stop the engine and use a stout branch as a lever to lift the trunk and free the saw (Photo 6).
After the trunk is free of branches and resting safely on the ground, cut it into manageable pieces, usually about 16 in. long for firewood. Start by cutting the trunk into 8-ft. long sections, a length short enough to roll over. Pick a spot on the trunk that has about a 3- to 6-in. gap under it. Otherwise your chain will hit the ground and quickly dull as you finish the cut.
Keep the bar parallel to the ground as you near the end of the cut, and finish with the bottom of the saw engine resting flat on the ground. That'll prevent the chain from accidentally hitting the dirt. Now use the process shown in Photo 7 to cut the longer sections into 16-in. lengths. With this method, you don't have to worry about your chain hitting the ground.
The Chain Saw Commandments
- Most chain saw injuries happen to the thigh when the operator is carrying a running saw. That's why chain saw pants or chaps are important. When transporting the saw less than 10 ft., carry it by the front handle only. That way if you trip you won't accidentally accelerate the saw and cut your thigh. When moving more than 10 ft., switch off the engine.
- Instruct everyone never to blindly approach the operator. The noise of the chain saw and the concentration required may make the operator oblivious to someone coming up from behind to announce lunch.
- Never cut alone. If an accident occurs, you'll need someone there to administer first aid and summon medical assistance.
- Keep your cell phone with you for emergencies.
- Understand the bar's kickback zone and avoid getting into kickback situations.
- Never cut above shoulder height.
- Work on the uphill side of trees so they'll roll away from you instead of over you.
- Use your chain brake! Whenever you aren't cutting, the brake should be in the locked, or “On,” position.
- Start all cuts with a full throttle before touching the wood.
- Never run a chain saw when under the influence of drugs or alcohol. When fatigued, rest!
- Protect your back. When trying to move logs, use a lever or get help.
- Avoid touching the ground with the chain because even a brief encounter will severely dull the cutting teeth.
- Keep the chain sharp. A dull chain is unsafe, hard on both the bar and chain, and it overworks you and your saw.