There are few tools as integral to job efficiency in the tree care industry as the chain saw. The use of this tool high in the tree is a key component, and challenge, to any tree crew’s safety and productivity.
Small, lightweight climbing saws, and their sometimes-needed heavier cousins, are part and parcel of getting wood on the ground on a daily basis. However, the location of their use, aloft often in exposed, isolated, challenging positions requires different techniques and methods than when the operator is securely ensconced with both feet on the ground. Operating a chain saw efficiently aloft is not as simple or as safe as when bucking up trees on the ground or felling trees, and it requires that operators understand and develop the skills and techniques necessary for this uniquely challenging situation.
Whether the saw in question is being run climbing with spurs, rope and harness, from a crane, or on an aerial lift platform, some basic rules and methods will increase the likelihood that everyone goes home with all their pieces and parts, while the tree bits all end up where they’re supposed to.
Just as it is when using a chain saw on the ground, personal protective equipment (PPE) is required for chain saw use aloft. Required PPE includes a helmet/hard hat and hearing and eye protection. While chain saw-resistant chaps or pants may not be required for aerial chain saw use in your area, they are highly recommended. After all, a cut to the lower body while in the canopy of the tree, isolated from other crew members’ help or first aid support, is even more threatening to life and limb than when you’re cutting from the ground and help is readily available. Chaps or chain saw pants while cutting aloft are simply cheap “insurance.”
Chain saws are intended, and required, to be used with both hands regardless of the operator’s location of use. One-handed chain saw use is an excellent way to lose a few fingers or function on the non-cutting hand, not to mention the previously discussed lower body injuries. In most cases operators who feel they need to cut one-handed will find that a change in position or technique can eliminate this “need.”
Operating a saw when climbing aloft requires the use of two methods of attachment, such as a climbing line and work-positioning lanyard. This is to provide a backup in case an errant cut severs one of the attachment methods. In addition, the use of two methods often puts the operator in a more stable position while making the cut, particularly when they take the time to have rope/lanyard angles opposing one another.
Climbers or aerial lift operators should always have a handsaw with them when working aloft, and will find the use of a straight blade an excellent way to finish chain saw cuts in a safer, more controlled manner. However, the sharpness of modern handsaws makes the use of a secondary or lanyard system during their use an excellent idea, as a number of accidents with climbing systems have taken place aloft when only a handsaw was being used. Fans of lanyards with wire cores should remember to avoid their use around energized lines, and that they are not an excuse for poor or shoddy saw control. Testing has shown that some wire core lanyards under the load of a climber’s body weight can be cut by a running chain saw.
Say hello to my little friend
In this case, what the operator is “saying hello” to is not all that friendly, for it is the ever-present possibility of kickback. As experienced operators know, contact with the upper corner of the tip of the chain saw bar will cause the saw to kick back violently toward the operator. This is obviously important on the ground, but even more so when aloft, as the climber has limited escape/positioning options.
Knowing and recognizing the causes of kickback and avoiding them will reduce the risk of it occurring. An additional consideration is the positioning of the operator’s body while cutting aloft, or simply staying out of the path of possible kickback. Cutting with the bottom of the bar with the saw held horizontally in front of the operator puts one’s face in the direct line of kickback, but repositioning in order to cut with the top of the bar removes the climber from the immediate path. While this is not always possible, it should always be considered, meaning the operator is situationally aware of the possibility of kickback and is as prepared as possible.
The mismatch or snap cut is a simple and efficient technique when cutting aloft, as it allows the operator to sever the piece while leaving it in place, safely stow away the chain saw, and then snap the piece off and throw it to the desired landing zone, all while avoiding one-handed chain saw operation.
Discussed previously in columns on dealing with hazard trees on lines or houses, this technique can also be used for horizontal branches or vertical spars, though the location of the cuts will vary with orientation and species.
Two staggered cuts are made with the chain saw on either side of the piece to be removed. The distance between the cuts will vary with species and size. For example, more brittle wood and smaller-diameter trees will require the cuts be made farther apart, while stronger wood and larger-diameter trees will necessitate the cuts be made closer together. The two cuts should overlap each other in the middle of the piece. The piece is now technically severed, but if the cut has been done correctly, the remaining fiber in the vertical plane will keep the piece in place until the operator can stow their saw and snap the piece off. The presence of a straight-bladed handsaw will allow the climber or operator to “take a little more off,” if the first cuts did not overlap enough without requiring one-handed chain saw use.
Pop the drop
This traditional cut, often called the drop or jump cut, has been part of climbing arborists’ repertoires for generations, but requires a slightly different method when being performed with a chain saw. When carried out with a handsaw, it is illustrated in many books/guidelines as consisting of three cuts: one under the branch nearer to the trunk; one on top of the branch away from the trunk and undercut to separate the branch; and a final cut to remove the stub.
This method works quite well with a handsaw, but can cause some major issues with a chain saw, as the staggered kerfs of the chain saw cuts can grab the chain as the wood separates. This “snatching” of the chain has given more than a few climbing arborists some anxious moments, and in some cases has led to serious injuries and even deaths. The chain grab is easily prevented by slightly manipulating the locations of the cuts. In most instances, operators who place the second cut directly above the first (undercut) will have little problem with chain snatching.
Though typically thought of when felling trees from the ground, the use of notches when aloft is very valuable when tops, branches or pieces of wood need to be “felled” in a particular direction or spot. Operators should use the same process to determine lean, size of hinge, desired direction, etc. that they would use during ground felling operations.
The use of open-face notches is recommended, though climbers should always consider what arc of movement they need the piece to go through and adjust the angle of the face notch accordingly. For example, when removing a top that is straight up and down, a notch at an angle of greater than 90 degrees will cause the hinge to continue to function as the top heads to the ground, thereby increasing the “ride” that the climber will get, regardless of whether the piece is attached to a rigging system or not.
A good guideline for top removal is to open the notch to an angle that will cause it to close when the top is almost parallel or parallel to the ground, thus lessening forward movement of the remaining tree. A 45-degree notch used aloft on a straight up and down top will maximize the amount of “push back” the tree is experiencing when the hinge breaks, also increasing the ferocity of the ride for the climber.
Notches may also be used when tip tying and lifting branches in rigging operations, after all the operator is now felling a branch upward instead of down. The size of the notch is determined by making one cut parallel to the ground/horizon and the other perpendicular to the branch orientation. This forms a notch that will close when the branch is vertical, assuming the block lifting the branch is located as close to directly above the face notch as possible. Closing the notch slightly will lessen the likelihood that the climber will have to come back in and sever the still attached hinge to free the branch; however, if this is the case, it is another excellent opportunity for the use of a straight-bladed handsaw rather than a chain saw.
Operating a chain saw aloft presents unique challenges in comparison to ground operation, but an understanding of some of the basic principles and forces of the saw, and the simple techniques discussed here, will go a long way toward ensuring safe, effective operation. In many cases, accidents and injuries can be prevented and productivity increased simply by following basic safe operation standards and good positioning techniques, coupled with enough situational awareness to realize that a particular scenario requires more thought and examination prior to starting the saw.