Recently, Girard Tree Service LLC, which I co-own and operate with my wife, Heide, was asked to take down a lightning-struck white pine tree (Pinus strobus) on an island here in New Hampshire. Due to the remote location and terrain, everything would have to be climbed and rigged down by hand. On top of that, there were no adjacent trees for me to remotely tie in to and use as a backup, so I was going to have to stay tied into the tree for the duration of the work. (Photo 1)

Hazardous trees call for technical rigging
Technical rigging work on hazardous trees in isolated places like this is our specialty, so I was looking forward to the challenge. I will say that we never take trees like this for granted – or any other tree, for that matter – and if for any reason you ever feel uncomfortable or have a bad feeling while working on any tree, listen to that inner voice of reason. It just may save your life.

I usually go out to look at a job prior to taking on the work; however, for this particular tree, all I had were pictures the homeowner emailed me. So I made sure we loaded up our small, 16-foot, open-hulled Lund work boat with more than enough climbing and rigging gear to safely do the work. My boat resembled Santa’s overloaded sleigh on Christmas Eve, with all our equipment plus me and my two climbers/ground workers. It is probably a good thing that New Hampshire State Police Marine Patrol did not stop us, but I knew we were still good with the load capacity of the boat.

We do a lot of remote island work, working well into December and a few times in January. This opens up a whole other level of job planning – factoring in wind, snow and bitter temperatures. There are not a lot of contractors working out on the islands at that time of year, so factoring in emergency rescues also needed to be taken into consideration. (Photo 2)

Luckily for us, this was in springtime, and the weather was fine.

Job-safety analysis
The first thing we did when we arrived on the island was review our job safety analysis (JSA) and perform a full tree-risk-assessment analysis, following the Tree Care Industry Association’s “Best Practices for Rigging in Arboriculture” tree-risk-assessment guidelines. Tree work is an inherently dangerous job, as everyone knows, and climbers must perform a tree and site inspection before beginning any climbing or rigging operation. There are four categories to be aware of when doing a tree-risk evaluation:

1. Low risk.
2. Moderate risk.
3. High risk.
4. Critical risk.

So much detail goes into evaluating whether a tree is safe to climb that it is beyond the scope of this article. Please refer to the “Best Practices for Rigging in Arboriculture” manual for additional information you will need to make a sound judgement.

This particular white pine tree was struck by lightning a number of years ago, and though it did not initially kill the tree, it did weaken it and eventually cause rot and decay to occur throughout the stem. It had suffered a side strike and showed the classic signs of vertical stripping of the bark and wood, along with spiraling around the trunk like a candy cane. Although at first it appeared to be superficial decay only, upon closer inspection and by sounding the tree, there also appeared to be hollow and decayed wood within the trunk itself.

The power of lightning is tremendous. A typical strike to a tree carries an estimated 300-million volts and 30,000 amps of electricity. This vaporizes the water inside the tree, creating superheated steam that can explode when it exceeds the structural strength of the wood. Mechanical and structural damage to a tree may be very slight to the point of being almost unnoticeable, or it may be so severe that it looks like a bomb exploded from within the tree.

Give careful consideration to lightning-struck trees
I cannot stress how dangerous working in lightning-struck trees can be. Many of us older readers of TCI Magazine remember the tragic death of Peter S. Donzelli, Ph.D., back in 2000 while working in a white pine that had been struck by lightning. For younger readers who may not remember Dr. Donzelli, he was one of the coauthors of the classic book, “The Art and Science of Practical Rigging,” which was published back in 2001 and was dedicated to his memory. Donzelli was a mechanical engineer, but his passion was arboriculture, and he worked many years as an arborist. The research in engineering concepts of tree removal that he did really helped contribute to the advancement of our professional knowledge of rigging techniques.

I always keep Dr. Donzelli in the back of my mind when I am about to work in a lightning-struck tree. Also, having climbed and rigged in them numerous times before, I knew there could be additional hidden internal defects all the way up into the canopy. Estimating the amount of decay and wood strength takes years of training and experience, as well as a continuing study of wood and its structural properties.

Preparing for a level-4 critical-risk removal
I classified this tree as a level-4 critical-risk tree, too hazardous to climb and/or rig to itself without doing a significant amount of mitigation work in preparation.

The first thing I did was to climb just above the primary signs of external decay (approximately 20 feet up) to install a small haul pulley, which would allow my ground crew to lift material and gear up to me. I planned on using a number of 4- x 4- x 6-inch pressure-treated timbers and 10,000-pound load-binder straps to act as “tree splints.” This is similar to what you might do if you were to temporarily splint a fractured arm or leg to stabilize it before seeking further medical treatment. We have used this technique on other lightning-struck trees, as well as on trees splitting apart from wind and storm damage, that needed to be removed. (Photo 3)

These were freshly pressure-treated wood timbers, and they were heavy for me! I will be 59 years old in a few months, and anything I can do to make the daily work of a production arborist easier, my body thanks me for the next morning. So I was very glad I had installed the haul pulley. Usually when I install load-binder straps, I space them 5 to 6 feet apart, but on this tree I decided to space them 2 to 3 feet apart instead, due to the visual decay present.

After the straps were installed, I continued to climb, inspecting the tree and removing small branches as I ascended. I did not have to rig the lower branches, but instead used a bypass snap cut and was able to use the “cut-and-chuck” method. Halfway up, I discovered another severe pocket of decay, so I installed an additional set of timber wood and load-binder straps.

This pine leaned toward the docks and water. To increase the margin of safety in the rigging work ahead of us, I installed two guy lines and spaced them about 90 degrees apart from one another, opposite the head lean. (Photo 4) If you picture the face of a clock, the head lean was at approximately 4 o’clock and the guy lines were installed at 9 o’clock and 12 o’clock. The lines we used were half-inch Samson True Blue and half-inch Sterling Atlas. These were pretensioned slightly using a CMI Rope Jack and then anchored off to individual Buckingham Port-A-Wraps.

At this point, the tree felt significantly more stable, and I climbed up to a point where I was planning to top it out. The tree was approximately 80 feet tall, and I set the block at about 70 feet. (Photo 5) I used a Rock Exotica 2.6 Swivel Omni-Block (working load limit, or WLL, of 20 kN) and a half-inch Samson Tenex spliced-eye rigging sling. I also wanted to make sure this tree was going to be loaded into compression while negative rigging, and not into tension.

The lowering line we used was another half-inch Samson True Blue. It was not run straight down to the base of the pine tree to a lowering device (LD), as I did not want to set up a large bending-moment arm, nor did I want to load the tree in tension. Instead, I ran the lowering line down at an angle of approximately 45 degrees to an adjacent white pine, at about 11 o’clock on my imaginary clock, and into a new Holdfast Lowering Device (I plan on doing a future article about this clever lowering device).

Installing the rigging line and hardware in this manner achieved multiple things for me.

• It provided my ground worker (who was running the LD) with a safer place to stand away from the drop zone and hazardous tree.
• Additional rope was added to the rigging system. Any time you can add more rope to your system, you increase the energy absorption and manage the forces better. This is due to having more elongation (stretch) with the additional rope that was added to the system.
• It reduced forces on the rigging system. By changing the angle into the block (opening up the angle more) and having the LD located on another tree, I was able to lessen the reaction force on the rigging point and, as previously mentioned, load the stem into compression rather than tension.

There are more reasons why you may want to move your LD to another tree. For additional information, I encourage everyone to read the article, “Seven Great Reasons to Relocate Your Lowering Device,” by my colleague and friend, Anthony Tresselt, in the July 2022 Tree Care Industry Magazine.

Topping out the tree
At this point, we were ready to top out the tree and block down pieces. I made sure to pre-tension each piece before cutting it. This is very important, as it helps limit the fall distance and reduces that initial hit as the piece is caught by the rigging line. This reduces the shock load on the stem and climber.

Shock loading is the sudden impact from a load coming rapidly onto a slack rope, also called dynamic loading. The following is a good rule of thumb and comes from my friend and mentor, Don Blair: For every foot of fall, the piece gains a unit of weight plus one. (Example: A 500-pound chunk falling 4 feet will hit the rigging at about 2,500 pounds).

My ground crew did an excellent job of letting the pieces run smoothly, and we were able to rig everything down safely in conservative lengths of 5 feet to 6 feet each, with each piece weighing in the 250- to 350-pound range. We blocked everything down to around 20 feet, and I left a block-and-rigging line in the tree to use as a DWT (double-whip tackle) to help pull over the tree. We also made sure to put a butt-tie on the stem, just above and below the face notch, to prevent the butt from kicking up and “fishtailing” sideways and damaging the new wooden steps leading down to the docks.

Conclusion
Everything came down just as planned (Photo 6), and I was able to show (even though my crew already knew) that climbers can sometimes work in critical-risk trees if the necessary training, knowledge, precautions and mitigation steps are adhered to. But again, it is always up to the climber to decide if the job can be completed safely.

I have lost count of the number of critical-risk trees I have climbed over the years, and I didn’t consider myself lucky at playing Russian roulette in any of them. I will always do my best to make sure that every mitigation step has been taken to prevent a catastrophic accident or fatality!

Chris Girard is an ISA Certified Arborist, a Society of Professional Rope Access Technicians (SPRAT) Level 1 Technician and co-owner of Girard Tree Service, a 17-year TCIA member company based in Gilmanton, New Hampshire.