By Michael Tain
Some form of planning process should be an integral part of any work activity in tree care operations. This planning process will not only help to ensure the safety of all crew members involved, but can also greatly increase the efficiency of the crew as a whole, allowing them to complete jobs more safely and quickly. Although this planning process is vital in all aspects of tree care operations, it is of particular importance during activities involving the use of a chain saw, such as felling and cutting, during which recent studies have shown approximately 35 percent of tree care worker fatalities occur.
The planning process for felling and cutting should not require a great deal of time, energy and paperwork — or even the use of electronic devices such as laptops or PDAs — but it should always be carried out prior to starting the chain saw. It should contain various basic components that will affect the felling/cutting operation; and once it becomes a part of an individual’s standard work practice, can simply be done mentally rather than verbalized. Obviously, in joint operations involving the participation of other crew members, the plan should be discussed so that everyone is aware of his or her individual role and responsibility.
The five key components of a felling/cutting plan are the height and hazards, the lean, the escape route, the notch and hinge, and the backcut. The integration of these five components into the plan, whether felling on the ground or cutting aloft — and carrying the plan out — will help climbing arborists ensure they have examined and prepared for all the variables involved in cutting or felling trees; and assure themselves of a greater degree of safe success and efficiency.
1) Height and hazards: The first step of the plan is meant to remind the user to gather some very basic, but quite important, information. Are there any existing hazards involved with the tree or piece to be cut? Will the cutting or felling operation create or magnify hazards to the operator or crew? Will the tree or piece fit in the desired target area or landing zone? The hazard information may be gathered through the use of visual inspections, such as outer and inner perimeter assessments. It can be supplemented through the use of pull/load testing, root collar evaluation, and even invasive techniques to evaluate the soundness of the wood fiber. The height of the tree or piece may be determined through the use of simple field techniques or more advanced techniques involving devices such as clinometers and range finders. The important factor is not how in-depth or technical the chosen method is when evaluating height and hazards, but rather that this evaluation is done; and that the resulting information is incorporated into the felling/cutting plan.
2) Lean: Knowledge of the existing lean, whether it be to the side, back or front of a given tree or piece is vital information to be gathered prior to cutting, because gravity is the law regardless of location. Operators who fail to take lean into account and integrate the lean into their plan accordingly, will invariably have trees or pieces end up in places or locations chosen by gravity rather than the operator. The evaluation of lean solely from a visual examination of the trunk can be deceiving, and can lead to a complete failure to correctly identify lean. A more appropriate and proven method of evaluating lean is to take into account the entire biomass of the tree or piece, and draw a straight line through the middle of this mass, as can be seen in Illustrations 1 and 2. This straight or plumb line’s location on the ground will not only more accurately represent the lean, but also enable users to estimate how many feet of lean are present. Additionally, lean is best determined away from the tree rather than close to the trunk or beneath the canopy. The most favorable location to accomplish this is 90 degrees from the direction of fall for front or back lean, and in line with the direction of fall for side lean. Methods and techniques to deal with lean will be examined in greater detail in future articles, but operators should recognize side lean as their greatest challenge, and attempt, if at all possible, to eliminate it through their chosen direction of fall.
3) Escape route: The identification, establishment, and use of an escape route increases the safety and survivability of a chain saw operator. Evaluations have shown that 90 percent of the injuries and fatalities that occur during felling operations happen during the first 15 seconds of tree movement within a five foot circle around the stump. Establishing and using an escape route will assist greatly in getting users out of this five foot circle in a timely and expeditious manner. The escape route should not be in the opposite direction of the falling tree due to the possibility of tops breaking out, the trunk kicking backwards off the stump, etc. Instead, the safest direction for escape is at a roughly 45-degree angle back and away from the stump and direction of fall to either side. If side lean does exist, the side the tree is leaning toward should be considered the “bad” side, and the escape route should be at an approximately 45-degree angle on the opposite or “good” side. Obstacles and tripping hazards along the escape route should be removed or taken into account as part of this step in the plan.
4) Notch and hinge: A face notch is a directional felling cut into the side of the tree facing the intended direction of fall and consisting of two cuts. The hinge may be thought of as a long board running through the tree or piece to be felled, from the base to the top. Assuming the hinge consists of good wood fiber, it provides the operator with the control to fell the tree in the intended direction, and does not break until the face notch closes. Advantages and disadvantages of a variety of notches will be discussed in greater detail in future articles, along with more focus on hinges. But regardless of notch or hinge choice, users should strive to avoid creating a bypass whenever cutting the face notch. Bypass is when the two cuts forming the face notch do not meet cleanly, and one extends beyond the other, compromising the ability of the hinge, the user’s primary method of control, to function correctly.
Open face notch
5) Backcut: The backcut component not only helps the operator determine which cutting method he or she will employ to establish the hinge and release the tree or piece; but also includes the evaluation and use of any additional means to overcome back or side lean, and a means to prevent a possible barber chair in the event of severe front lean. The hinge’s thickness or width should be between 5 and 10 percent of the tree’s diameter, dependent on species and situation, but should never exceed two inches. Even width or thickness along the hinge’s length will provide maximum control; and there is no advantage gained by leaving the hinge thicker or thinner on one side or the other. The removal of pieces in a spar pole situation will require much thinner hinges due to decreased leverage. The use of a bore or plunge cut to establish the hinge is a safe and accepted practice, and has the added advantage of eliminating the possibility of barber chair. However, chain saw operators should be well trained and practiced in bore cutting in controlled circumstances prior to employing it in actual work situations. Only the lower quadrant of the tip of the bar — the “go” or “starting” corner — should be used to begin a bore or plunge cut. And in felling situations, the bore should be started well back from the desired hinge thickness to allow the operator to make
adjustments for error without compromising the hinge. Users employing the conventional or 45-degree face notch should use a “stepped” backcut in which the backcut is elevated slightly, one to two inches, above the apex of the notch. This step will create a ledge, helping to prevent the tree from kicking back off the stump when the hinge breaks as the face notch closes. Care must be taken when using a “stepped” backcut to evaluate hinge width or thickness from the apex of the notch, not the face of it, as an evaluation or estimation from the face can easily result in the hinge being completely cut through and compromised. Chain saw operators using the open face notch need not concern themselves with “stepping” their backcut, as the tree or piece will have already passed through the angle of maximum push back, 45 degrees, before the face notch closes and the hinge breaks, thus the possibility of the tree kicking back off the stump is highly unlikely. The plan for the use of wedges, pull lines, and guide lines to overcome back lean or combat side lean is also formulated in this step. Users should evaluate how many wedges are needed or how much pull is required from the information gathered in the height and lean sections, and put the necessary methods in place prior to carrying out the felling/cutting plan.
The five-step felling/cutting plan, once integrated into a tree care professional’s standard work practices, cannot help but to increase safety and efficiency. The use of some form of mental checklist prior to every cut, verbalized or written as required by particular situations, will ensure that all the key components of a successful and safe felling or cutting job are examined without requiring a great deal of time. Ignorance may be defined as being unaware or not noticing that a particular hazard or situation existed, and discovering its existence too late with perhaps tragic results; while stupidity may be defined as being aware that the particular hazard or situation existed, yet going ahead anyway. Hopefully all professionals strive to avoid stupidity — the use of a five-step felling/cutting plan can help them avoid ignorance, and the tragic results it may bring about.
Michael (House) Tain is a contract climber, splicer, educator and writer associated with North American Training Solutions www.northamericantrainingsolutions.com and Arbor Canada Training and Education www.arborcanada.com. He is currently located in Lancaster, Ky., and can be reached via e-mail at firstname.lastname@example.org.