Photo 1: Multiple slings can help to reduce rolling.

Whenever I am asked to speak about working with cranes, I always start by discussing the accidents that are happening. This is the foundation for what we should all craft our practices around in order to ultimately avoid the problems others have had. What slings to use, how to attach them, where to make the cut, what cut to use and so on should be derived by the overarching desire to work safely above all else. And sacrificing safety for time will ultimately cost you way more than it saves, including the time you are so desperately striving to capture.

Photo 2: The cow hitch does not weaken the sling, and is just like using a loop sling, round sling or eye-and-eye. All photos courtesy of the author.

Number of slings
One of the most frustrating discussions I often have when talking about this topic, especially with more seasoned climbers/riggers, is how many slings to use and how to attach them. It almost feels as if using only a single round sling is a badge of honor that signifies how skilled you are.

The truth is that it is the other way around. What I see as a commonality among the most elite in this business is a depth of knowledge and a willingness to use any technique a given situation calls for. Limiting yourself to using just one method for all scenarios limits your potential to solve unique problems and can hinder success.

Many incidents stem from improper rigging. When a load shifts, flips or moves quickly, bad things tend to happen. In fact, many crane-tipping accidents happen not from overloading, but from the load shifting to a more distant radius. I am a big fan of limiting movement to enable a more static capture of the load and, at the same time, to reduce uncertainty (which adds stress) for the operator.

When you are in the seat of the crane working at full radius, it is nerve testing and can make decision-making more difficult. If you can guarantee the piece stays static throughout the lift, it makes life simpler and increases success rates.

Capture center of gravity
The question now becomes, how do we limit this negative movement? The first way is to capture the center of gravity as perfectly as you can. This certainly can be done with a single sling, especially with a symmetrical piece or tree. The more difficult lifts are irregular in shape and have limbs extending in awkward directions. That is when you may want to consider adding slings and possibly changing the style of sling to better assist you in capturing the center more easily.
Fully adjustable slings are my first choice for this situation. I tend to go to the slings that I helped design for Teufelberger, that are constructed with a polyester cover over a Dyneema core. These slings are very lightweight, high strength and extremely low stretch. The cover helps to protect the core from pulls developed from grabbing on rough bark, and they tend to untie more easily due to their firm, round shape.

I will use as many of these slings as needed to do the job. Many times this means using only one or two, but three can be a big help to reduce rolling. (Photo 1) On a rare occasion, I have even used a fourth sling when the load was very brittle or irregular and required more attachments to ensure a proper lift. I typically choose either a cow hitch or timber hitch, depending upon the amount of sling I have to work with.

Photo 3: The wall cut may be used to create a barrier between the piece and an obstacle, such as a wire, structure or even yourself.

Photo 4: The shelf cut also is, ultimately, a wall of sorts, but instead of protecting an obstacle, the shelf supports the piece so that gravity cannot pull it down.

Knots in anchor slings
I should address one common argument that can arise when talking about using knots to anchor slings. Some OSHA language leads some to believe that you cannot anchor with a hitch/knot. The truth is that this language was designed to keep riggers from using knots in nonadjustable slings (e.g., eye-to-eye nylon webbing) to shorten them to make them adjustable. In other words, say, to tie a figure-eight knot (or similar) in the middle of the sling in order to shorten it. This would weaken the sling temporarily while the knot is in place, and could lead to overloading.

This is not the same thing as using an approved hitch to anchor the end of the sling with a cow hitch. (Photo 2) The cow hitch, after all, is simply a girth hitch, just like using the loop sling, round sling or eye-and-eye. If this still doesn’t suffice in your area of the world, then I would suggest using one “approved” sling to hold the entire weight and then adjustable slings as “balancers” to comply with your regulations or policies.

Selecting the cut
The second part of the equation for better control is to match the right type of cutting procedure with the rigging. And, to be completely transparent, the most common cut I employ daily is the straight cut. The reason for this is to sever the piece as quickly as possible. Once you find the center of gravity and place the hook there, apply the proper tension and incorporate the right rigging, the only thing left to do is release the piece so the crane can do its job. The faster this takes place, the more efficient the entire operation becomes.

This is also the reason you will rarely see me using a top-handled saw on a crane removal. Nowadays, our saw selection is way lighter and more powerful than previously, making it a great choice to take a more powerful saw into the tree at the start.

Photo 5: A two-sided wall, or “V-cut,” can be used to limit movement in two directions.

Purpose-specific cuts
When certain scenarios arise where there is very little to no room for error in controlling movement, I would select a more unique cut that will serve a particular purpose.
The “wall cut” is one modification I may use that would create a barrier between the piece and an obstacle like a wire, structure or even yourself. (Photo 3) If the load starts to move toward the obstacle, the “wall” will prevent it, and the crane can then make an adjustment to pull it away. This, ultimately, is an insurance policy against striking something you need to protect without incorporating additional rigging gear or co-workers. If the piece pushes toward whatever you are trying to protect, the wall will stop the piece from moving and allow the operator to counteract that movement before the lift commences.

Another similar cut to the wall cut is a “shelf cut.” (Photo 4) This also is, ultimately, a wall of sorts, but instead of protecting an obstacle, the shelf supports the piece so that gravity cannot pull it down. I use this quite a lot with longer limbs/leads where the butt may want to drop when released. The shelf will now keep the piece supported until lifting, thus reducing the chance of shock loading or dropping off of the cut abruptly.

A two-sided wall cut is an additional protective measure you could incorporate to limit movement in two directions. I refer to this style of cut as a “V-cut,” where two cuts that bisect one another can be used in opposing directions that capture the piece until the lift is initiated. (Photo 5) This cut is something I use when the section may want to pull away from the cut or push back into the cut due to an irregular shape or an external force, such as wind.

It takes the guesswork out of trying to predict the most likely movement and eliminates the need to pre-tension with the same amount of exactness a straight cut may require, since the piece will be locked in and can’t move until lifted. In this instance, the piece will be completely severed and will sit in the V-cut and allow the operator to begin to lift when the time is right. If you see the piece pushing hard or pulling away, minor boom corrections can now take place while the piece is still locked into the cut.

Conclusion
These are just a few ideas I tend to share when discussing crane use. Like any discipline in tree care, science, mentorship, experience and practice are all components of a recipe for consistent success. There are many ways to perform a tree removal. It is up to the practitioner to make the right choices at the right time in order to succeed. And please do not hesitate to enroll in a class or sign up for a workshop, even if you are proficient already. This is how we stay engaged and help move the needle of the industry. And remember, work harder and smarter!

Mark Chisholm, CTSP, is c0-owner and director of operations with Aspen Tree Expert Co. Inc., a dual-accredited, 37-year TCIA member company based in Jackson, New Jersey. He also is a spokesperson for Stihl Inc. and an ambassador for Teufelberger and Kask.

This article was based on his presentation on the same topic during TCI EXPO ’23 in St. Louis, Missouri. To view a video created for that presentation click here.