The tree care industry has taken advantage of the capabilities of construction cranes and similar pieces of equipment for quite a few years, but the last 10 to 20 years have seen a large increase in their use throughout tree care, regardless of geographic location or market size.
There is no secret behind this expansion of crane use amongst climbing arborists, cranes are extremely useful, and in many hazard tree situations, vital pieces of equipment that can, if properly employed and operated, increase the safety and efficiency of many whole-tree removals, and even large pruning jobs in sensitive target-rich environments. Beyond these typical uses, tree companies with cranes in their inventory, or access to a rental unit with “tree work-friendly” operators, often find that these pieces of equipment have far more applications than they ever thought of. From simplifying and speeding the removal of large amounts of debris from “access troublesome” backyards to providing a safe tie-in point for a climber when working on a tree that is unsafe to climb, yet inaccessible to an aerial lift.
When any different or new piece of gear, method or technique is added to a tree crew’s physical and mental toolbox, knowledge, information and training must be part of the equation, lest inappropriate or unsafe use lead to a disaster. After all, larger things – and a crane, no matter how small and maneuverable, certainly qualifies as relatively larger – have larger, bigger and heavier consequences when things go wrong. There are a number of ongoing seminars, courses, demonstrations and hands-on field exercises pertaining to the safe use of cranes in tree care operations offered by different training companies and industry professional organizations, but as a minimum, an excellent place to start is the 2006 version of the Z133.1 (American National Standard for Arboricultural Operations: Safety Requirements), which has a section on crane use in tree care. Prospective arborist crane users should also keep in mind that their individual state or province might have additional rules/regulations/standards regulating tree care crane use and inform themselves accordingly.
Communication is a key element of all tree care activities, not only for the safety of those aloft and on the ground, but also for the efficient accomplishment of the task at hand. Throw a large motorized piece of equipment that towers over the work site into the mix, and communication becomes even more important. The frustrating experience of attempting to communicate effectively between the canopy and the ground is one that all tree crews are familiar with, adding the engine noise of the crane, a crane operator who may not be able to see the climber (and vice versa) and typically greater work heights all are factors that make communication during crane operations even more challenging.
There are a large number of communication systems available, ranging from simple hand/arm signals, such as illustrated in the appendix of the Z133.1, to voice-activated throat mikes and muff radio systems that can be fitted on existing helmets or hard hats. Regardless of which system is chosen, it is vital that all work participants know and understand the various signals or systems prior to the job beginning. Trying to remember what channel one is supposed to be on, or what the hand and arm signal for “boom up” is with a 5,000-pound piece of wood hanging free is not a good indicator that the job is going smoothly, let alone safely.
Additionally, situations that prevent the climber and crane operator from being in visual contact require that a spotter be used to not only carry out the important role of relaying signals, but, if necessary, inform the climber/crane operator what is occurring at the other end of the “stick.”
Crane and work site setup
Planning for crane and worksite setup should begin with the first person looking at, or estimating, the job. As much as is possible, everything that might affect crane operation and use should be considered and planned for, this includes traffic control requirements; size and capacity of the crane needed; suitability of ground and space available for crane use; power lines, septic tanks, overhead communication lines and other hazards; will additional cribbing or blocking be needed for the outriggers of the crane; is the tree safe to climb, or might a second crane be needed for a TIP; etc. Cranes are designed, constructed and intended to be operated in a uniformly level position on a firm surface that will adequately support not only their weight, but the additional weight they will be lifting and moving. In some situations, a great deal of time, energy and materials may be necessary to create an appropriate setup. Shortcuts or shoddy work in this area are an excellent way to end up purchasing a client’s newly crane bisected house, let alone the emotional cost of a possible death or injury to a crew member.
An additional part of this planning process should be the location of trucks and chippers in relation to the crane and tree for efficient removal of woody debris, saving time and energy by using a crane is not helpful if the branch managers have to hand carry every piece a great distance to the chipper.
How well or how poorly the crane is operated can often be the difference between a safe, efficient tree job and one that will give the company owner night sweats.
A tree company that owns or is interested in purchasing its own crane should be aware that some states and/or municipalities require licensing for crane operation; and given the amount of money typically spent on a crane, “on-the-job” training for the chosen operator may not be the best choice for long-term crane, crew and company financial survival. Crane operator training courses, though not always tree industry specific, are readily available in most states/provinces.
Should a tree care company prefer to rent a crane for individual jobs, they should request an operator from the company who is familiar with crane tree work, as it can be very different from construction crane use. Repeat business with a particular crane rental company can help both the tree and crane company know what they can expect from one another and grow more efficient in their tree crane operations.
Tie-in Points (TIPs)
Should a climber be using a crane as their TIP, there are a number of requirements of how they must secure themselves. Climbers can be lifted into the tree by a crane or use it as a tie-in point only when the person responsible for the work has decided a crane is the safest and most practical method available. TIPs should be secure, such as locking shackles, avoiding possible failures in the climbing system, should not interfere with any of the crane’s warning or operational devices, and should be designated anchor points on the boom or lift line.
Putting the work positioning lanyard through the hook, regardless of how it is attached to the climber’s harness, is not an appropriate or acceptable method. When the crane comes under load, the climber should be detached from the crane and attached to the tree itself, an adjacent tree, an aerial lift or even a second crane. If none of these options are available, or if they would create an unsafe situation, the climber may stay attached to a crane under load. When the climber is still attached to a crane under load, the operator must not exceed 50 percent of the crane’s load capacity at the existing boom angle and extension.
As strong and versatile as a crane might be, it is only designed for static lifting of loads, not for the dynamic forces of tree pieces/parts being “dropped” or felling into the load line or hook.
There is a wide variety of aerial chain saw cutting techniques that will assist climbing arborists in keeping loads as static as possible and avoiding unintended, and often catastrophic, dynamic loading of cranes. Excellent reference tools for crane operators and ground personnel are a green weight log chart or the Rigging Software 1.0 program loaded on a handheld device. Both of these will help the climber and operator be more confident about the weight of the intended lift and plan accordingly, particularly as it allows an operator with digital readout on the crane to put a roughly appropriate amount of lift on the piece prior to it being cut, helping prevent pinched saws or wild, sudden movements.
Obviously, the use of cranes in tree operations is a much more involved and complicated subject than the space available to discussed it here, but this introduction, in conjunction with additional knowledge and qualified field training, can help tree crews use this efficient piece of equipment not only to its full capacity, but also safely.
Editor’s note: This article was originally published in March 2011 and has been updated.