By Michael “House” Tain
A removed piece being lowered by a crane.
Photos courtesy of Scott Prophett
Cranes have a large number of appropriate applications within the day-to-day operations of tree care, from something as simple as safely removing large woody debris from a relatively inaccessible back yard to as complex as the complete removal of a tree that is too hazardous to climb and in a location that aerial lifts cannot reach. However, as with the addition of any new tool or technique to a system, climbing arborists must inform themselves about the safe appropriate uses of cranes, the proper techniques and methods when employing them, and the existing standards regulating their use within tree care operations. The 2006 version of the Z133.1 (American National Standard for Arboricultural Operations: Safety Requirements) has a section on crane use in tree care; and this is, at a minimum, an excellent starting point for tree crews considering crane use. In addition, consideration of a few basic ideas and principles of crane use, will assist tree care personnel in not only gaining the speed and efficiency a crane can provide, but help ensure that it is accomplished in as safe a manner as possible.
Effective communication methods are extremely important in any tree care operation, for both safety and efficiency, but they are even more vital when a crane has joined the operation. Most tree care personnel have experienced the frustration of attempting to communicate with one another from the canopy to the ground and vice versa. The addition of factors such as greater heights, the engine noise of the crane itself, and a lack of visual contact between the climber and crane operator all contribute to the need for a good communication system prior to even beginning the job. This not only limits frustration, but helps ensure that everyone, including the crane, goes home with all their pieces and parts. Hand and arm signals are one option, and an appendix in the Z133.1 provides a crane hand signal chart. If hand signals are used, they should be clearly known and understood by all members of the crew. In situations where visual contact between the climber and operator are not possible, a “spotter” must be used to relay signals between the two. Radios are another communication method, and some types can be quite effective and reliable. There are also radio systems available that replace the muffs on a hard hat or helmet — thus streamlining the process somewhat.
The set-up planning process should start with the first person evaluating the job. Factors such as the necessity for a crane, size of crane, suitability of ground and space available for set-up, power lines or other hazards, and the need for additional materials such as cribbing or blocking should all be part of this job evaluation. The crane should be uniformly level and on a firm surface with the operator testing the adequacy of the footing prior to any work taking place. Once the crane is properly set up, some thought should be put into the location of trucks and chippers for maximum safety and efficiency.
A large piece being picked by the crane from the backyard.Skilled crane operation can “make or break,” quite literally, their use in tree work. Tree care company owners interested in purchasing their own crane should be aware that some states and cities require licensing for crane operation. Should they wish to protect their investment, even in an area that does not require licensing, owners would probably be well advised to put their chosen operator through a training course rather than relying on “on the job” training alone. If renting a crane for a particular job, attempt to get an operator from the rental company who is familiar with tree care crane work, as the use of cranes in the tree industry is quite different from construction applications. Reoccurring and consistent crane rental will allow a tree company to establish a relationship with the rental company, helping both parts of the equation to know what they can expect.
Particular attention should be paid by climbing arborists to how they must secure themselves or tie-in when using a crane. A climber may be lifted into the tree or use a crane as a tie-in point only when the person responsible for the work has decided it is the safest, most practical method. Possible tie-in points include designated anchor points on the boom or lift line of the crane, but care must be taken to use secure methods such as locking shackles that do not interfere with any of the crane warning/operational devices while at the same time avoiding a chance of compromise to the climbing system. Attachment simply by a work positioning lanyard through the hook is not an appropriate or acceptable method. The climber should be detached from the crane whenever it comes under load either by attaching themselves to the tree itself, an adjacent tree, a second crane, or by using an aerial lift. However, if none of these alternatives are available, or if they would create an unsafe condition, the climber may remain attached to the crane under load. In this situation, the operator must not exceed 50 percent of the crane’s load capacity at the existing boom angle and extension.
Cranes should only be used for static lifting of trees or pieces and parts thereof. They are not designed — nor are they intended for — dynamic forces, and “dropping” or felling loads into them can result in catastrophic consequences. Climbers should be familiar with cutting techniques that allow the crane operator to lift the piece away smoothly and cleanly with no — or at least a minimum of — jerking or snapping. Pieces should never be felled into the hook or load line. Use of a green weight log chart, which should be available to the crew, or the Rigging Software 1.0 program on a handheld device, will help the crane operator and crew have a good idea of the weight of particular lifts. This in turn 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. Climbers, whenever possible, should rig the piece in such a manner to limit movement and swings once it is freed. Typically, centering the hook above the load to be picked will help minimize movement, although the climbing arborist must always take into account any branches that may “overload” the piece in one direction or another. Attention must be paid to the relation of the sling placement to the length of the piece, as slings placed and picks taken too low on the piece may result in it inverting or flipping over at a high rate of speed. The use of synthetic slings instead of steel chokers can ease sling placement and lessen the load the climber might have to struggle with aloft. In addition, slings made from the newer “exotic” fibers are often stronger than similarly sized steel chokers. The use of balancing systems can assist greatly in minimizing movement in vertical pieces with multiple branches or horizontal pieces that must maintain a horizontal orientation during the lift.
Cranes in tree care can involve a great deal more complexity in both operations and techniques than those discussed here, but for those considering crane use or tree care professionals who have only used a crane sporadically, these basic ideas and principles are a good starting point. Cranes are an invaluable resource for the tree industry, and can make many tree operations much safer and more efficient. But, as with any task or tool tree crews employ, knowledge, education and training will only lead to yet better and safer use.
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 email@example.com.