A two-lane road at 8 a.m. It is hovering around 34 degrees in the high Sierras of California, a few miles east of Quincy, a logging and resort town. A lazy wind plays with leaves by the side of the road. It is lazy because it doesn’t go around, it cuts right through me. A two-lane highway with traffic, mostly logging trucks – full ones and empty ones going in both directions – that pass steadily.
Normally these vehicles travel around 55 mph. Today, Mountain F Enterprises’ traffic-control crew keeps them to around 20 mph. If the crane crew asks, traffic can be stopped completely. The traffic slowdown stretches more than a mile and a half and involves six MFE employees with communication headsets, signs and paddles, all the necessary cones for direction and many years of experience. Since it is a highway, a California Department of Transportation (Caltrans) manager is on site in the morning, checking and approving the measures taken.
A steep slope on one side drops to Spanish Creek. If it were a ski slope, it would be marked on the maps as “double black diamond.” So, if you take a wrong step or load the crane too heavily, gravity could deposit you in the creek after a second or two of fall on a granite slope. That’s if you didn’t pull down one of six 60,000-volt lines between you and the creek. If something contacted those lines – any part of the crane, boom, rigging or tree parts – the fall would be a moot point. Electricity is always seeking ground, and that much current isn’t choosy about which path it takes. It doesn’t care how many bodies it must go through, either.
This is why the expert team of line-clearance arborists with MFE, a 12-year TCIA member company based in Folsom, California, is here today, including a crew leader, climber, the crane operator and one additional ground-crew member.
A National Manitowoc NBT 40 2 Series 40-ton crane with a boom of 127 feet is going to be used to take down three trees, each roughly 100 feet in height. This crane, besides its power, can be used with less than a full span of outrigger spread. In a situation with a cliff on one side and a lane of traffic on the other, it is essential to shrink the crane’s footprint. The largest of the trees is a cedar (Callocedrus decurrens) about 36 inches diameter at breast height (DBH). In total, the MFE team has about two days of work. The crew leader notes that there is no time limit on crane work.
The MFE hazard-tree crane crew is made up of four workers, one in the operator’s seat, two on the ground and one in the tree. They use state-of-the-art equipment and know-how to piece down some of the tallest trees on some of the smallest roads, in addition to properly navigating electrical lines.
Ignacio Montez, the crane operator, has more than 13 years’ experience in crane operation, some in residential situations. Lots around power lines. He came here to do what looks to be some of the highest-level, highest-stakes crane operations in the tree world. The crane was chosen for this job by Adam Stansfield, the area’s district manager, and Mike Placencia, regional safety supervisor, when they looked at the job site.
Stansfield is here today to make sure the job goes off without a hitch before he heads out to look at another crew. While we watch the setup, I mention to him a few crane-rigging experiences I had in the bad old days. He nods. “It used to be that everyone worked that way. We have to be extremely accurate around energized wires. You will see some things today you’ve not seen before.” He’s right, I did.
This work is garnished with the extra difficult, potentially deadly factor of live electrical lines. The usual primary power line in the backyards of California is about 12,000 volts of power. People who have formal or informal electrical hazards awareness training will remember that electrical lines are above ground, high up on a pole, to use distance to keep them safe. There is no “insulation” on these primary or distribution power lines. Space is what keeps those lines safe, and trees grow each year.
A line-clearance arborist or trainee can work just outside the minimum-approach distance (MAD), but no one else can approach closer than 10 feet to the least of the nominal-voltage lines. It would be impossible to gauge how many amps those thousands of volts could drive. This number depends on load, time of day and other conditions. But, as we know, it only takes about a tenth of an amp to start a human heart’s ventricular fibrillation, and that will usually result in death. And we also know that even one toaster, in one house, needs around 15 amps to brown the bread.
The team maintains the MAD and then some. These lines are 60,000 volts. The MAD for this project is 11 feet, and the tree stands about 15 feet away from the closest point. Not a large margin for error. The MFE crew has an impressively calm demeanor.
Casey Devlin, the crew leader, has 12 years of experience climbing and operating in production utility tree work. At the morning briefing, he asserts that he is all about safety. Questions pop into my mind as he reads the job-site-security form, but Devlin quickly covers any questions before they can be asked. For instance, I’m curious if they would operate even if the winds came up. “The winds are gonna pick up later, so we will see if we can still operate.” In these steep mountains, winds will ride downslope each afternoon as the air cools.
Devlin has already been working on the cribbing of that crane for more than an hour. He has it set, has the operator lift and “shake” the boom, then shakes his head, has Montez pull up all the outriggers and asks for a shovel. The crew grabs two shovels and makes flat, level pads out of unforgiving granite schist, then cribs it again. Now it’s right. He watches the dirt and gravel underneath as the crane boom moves quickly and stops with a slight jerk. This is so he can observe the pads and cribbing. He does this over and over with Montez, conversing calmly through the headsets. In a few more minutes, they are satisfied. The cribbing is going to be good.
“I am the responsible party,” Devlin says, reading down the list of roles and responsibilities. “Mike will be the climber today.” Michael Harach is 21 years old and in top shape, as most climbers are. He has more experience here on the hook and rigging than most arborists get in a lifetime.
When our orientation begins, Montez signs a paper that, among other things, names him as the operator. As a trainer and observer, I sign the stop-work order, as does each member of the crew and traffic control in that area, agreeing that if we see something questionable or unsafe, we will bring it up immediately and stop work until it is corrected.
These crews have done as much paperwork as I have ever seen in one morning, including an emergency-response plan, job-site-security sheets and notation of which hospital and fire stations are closest. This is MFE policy on all its jobs.
Devlin explains how the “footprint” for the crane is as long as possible on the downhill side and much shorter on the uphill side to accommodate the single lane of traffic. Since the truck faces downhill with the highway’s slope, the front, downhill wheels are easily a foot off the ground. With the road’s steep crown, the short-outrigger side fades downhill, so that must be figured in. Four outriggers and the back wheels anchor that crane to a mountainside. The land slopes in all directions from the crane.
Harach clips into the specially rigged tie-in on the crane and the hook. From experience, I know that the feeling of heading up on the hook is not as exhilarating as it appears from below. It is more a pit-of-the-stomach sort of thing. As most of you know, two tie-in points were a point of contention years ago, and are now the standard in the industry to allow crane entry into trees.
Transmission lines like these bring electrical power up the mountain from the valley. Over time trees grow larger and wider, and sometimes become unsafe due to their age or mechanical defects. That is why these trees are coming out. They have outlived a safe proximity to these lines.
The MFE hazard crew regularly works on huge trees, including cottonwoods (Populus section Aigeiros) and some of the largest black walnuts in existence down there on the fertile valley floor. Cottonwoods and oaks like the magnificent valley oak, Quercus lobata, can be more than 6 feet in diameter and have hanging strands of twigs, like willow, up to 30 to 40 feet in length.
“Each tree has its habit, wood weight and characteristics,” Devlin says. I ask about the habits of some of those woods. He says, “You have to know the brittle limbs of black walnut. Not a limb you want to crawl out on because it will break.” He thinks about it and smiles at a memory. “It comes with time.” He shows me the app he uses, LogWeightPro, and I add it to my phone.
I am curious how the top’s weight, and all weights, can be figured. From long experience with the trees, limb weight is figured separately, as a fraction (about 25% for this species) of the log weight. Each piece of stem is measured using a diameter tape in the tree, then measuring downward 10 to 15 feet and taking a separate diameter measurement. The increase in diameter is figured in with the limb weight. If Devlin likes it, he gives Harach the order to rig it (involving cutting in through the bark so the slings cannot slip) and get below to send one. If he doesn’t like it, he has Harach measure up a few feet.
Today’s first tree is a 34-inch DBH cedar. Devlin and his assistant, Anthony Hill, who processes all the brush, consult the green-log-weight chart and figure the weight of the pieces being picked. Protocols working around these hazards mean that the first pick is no more than 20% of the maximum the crane can lift at that height and angle. The next pick, and the next and next, assuming all goes well, can be 50% of the maximum.
In this deliberate manner, the crane can easily lift and pull away each piece, and the results are dialed into a precise matrix. Devlin explains that double-hitched tops can still twist slightly, due to limb weight, tree lean and other factors. By using the crane’s full power and the operator’s solid, tested ability, tops with limbs can be slowly lifted away from the hazards.
I decide to do the math. It’s a treetop, so you have to figure taper, length and limbs. The normal twist and whip of a top coming off have to be very much diminished. I’m still figuring, clicking on the app and scratching my head as the first pick, the tree top, comes to rest on the ground.
There can be great beauty in precision. Precision to solve the real-world problems of keeping electricity humming along, safely and reliably, to our homes and businesses. It is a pleasure to witness the precise communication, both visual and audible, of the MFE crew using both wireless radio in their helmets and a series of hand signals to safely and effectively coordinate their activities. I am able to watch the first few picks on the cedar tree and have a photo here of the “pick log” used. This log is kept to determine accuracy after the fact, which helps with the next pick and the next job.
Nobody is in a hurry, everyone keeps in constant communication and the job goes as smoothly as it can. Choreographed by Devlin, the traffic is occasionally stopped, just in case, but I never see the load swing over the lane that is open.
Jack O’Shea is a traveling crew trainer with ACRT, Inc., a 41-year TCIA member company based in Stow, Ohio. He is an ISA Board Certified Master Arborist, is ISA Tree Risk Assessment Qualification certified and in 2020 completed the American Society of Consulting Arborists (ASCA) Consulting Academy. He has been involved in the tree care industry for more than 30 years, and specializes in land-use issues and construction mitigation for trees.