With up to a half-million dollars in equipment to protect, not to mention personnel safety and potential liability if something goes wrong on the job site, sometimes it’s the little things that save the tree care day. Take, for example, mats, pads and cribbing for cranes and aerial lifts.

“Mats make a big difference when going across a yard,” says Peter Nieves-Sosa. Photo courtesy of Peter Nieves-
Sosa.

For the uninitiated, mats are used beneath the crane or aerial-lift carriage as it moves across terrain, whether it be on rights of way, a driveway or a lawn, or just transitioning from a driveway to turf. Pads and cribbing, typically, are used under outriggers.

Cribbing is used, sometimes creatively, to level the crane on uneven ground. Photo courtesy of Dave O’Neill, CTSP and co-owner of High Canopy LLC.

Following here, four industry veterans, each with a good amount of crane and lift work behind them, discuss what to use and when to use it to keep lifts and cranes on solid footing – literally.

Peter Nieves-Sosa
Peter Nieves-Sosa is president of The Crane Man Inc., a 14-year TCIA member company based in Chalfont, Pennsylvania. His is a crane rental company (crane and crew) specializing not only in large-tree removal but also jobs such as truss work, HVAC lifts and other specialized lifting. Nieves-Sosa also runs an annual Crane Safety Climber School for the tree care industry, celebrating its 13th year this past August. The company runs three sizes of cranes, rated at 36-, 45- and 55-ton capacities, with vehicle weights of 56,000 to 77,000 pounds.

“Mats make a big difference when going across a yard,” says Nieves-Sosa. “We use different brands, but they all are made of the same material, HDP, high-density polyethylene sheets. Essentially, they are 4-foot by 8-foot sheets of plastic plywood.”

He explains that, while there is some traction benefit associated with the mat’s tread, the greatest function is weight disbursement to minimize impact to the ground beneath, given the weight of a machine such as a crane, not to mention its eventual load. “When we drive onto a property to access the backyard, for example, we want to minimize impact as we go, so we pick them (the mats) up after traveling over them and set them down the path as we go. The objective is to tread as lightly as possible and not leave tire tracks – maybe hit it with a leaf blower and nothing will show,” he muses.

Nieves-Sosa uses a pad made of composite ply materials, typically 30×30 inches and 3 inches thick. Photo courtesy of Peter Nieves-Sosa, of The Crane Man Inc.

“Let me throw out a disclaimer,” Nieves-Sosa interjects. “Mats work well, very well, but they are not magic. The weight still exists, but it does help.

“My personal preference is to lay sheets as we go unless we are doing a long straight line,” he explains. “When turning, it’s easier to move one mat at a time. It takes only seconds to pick up the sheets. They have molded-in handles. Each weighs about 80 pounds, and they seem to get heavier at the end of the day.”

Once in position, first a pad goes down for the outrigger to land on, according to Nieves-Sosa. These, too, are composite ply materials, typically 30×30 inches and 3 inches thick, with rope handles. Next comes the cribbing if needed. He adds that the pads are used to help distribute weight even under an outrigger landing on macadam (pavement).

Cribbing, also called dunnage, is used for assembling a base, typically wood (oak is considered the strongest), and to aid in leveling the crane. Unlike bucket trucks, crane tires have to break contact with the ground and the crane has to be set within 1% of level. “So sometimes on a hilly setup, we have to crib-up (use lumber to build up the outrigger landing pad) to get it to level, while sometimes it’s necessary to dig in the high-side outrigger,” he says.

“OSHA used to require an assembled base of three times the surface of the outrigger pad, but has done away with that wording, stating it needs to be sufficient to support the crane and load,” he explains.

Nieves-Sosa continues, “Each crane carries a bit of different cribbing to address different needs, 6×6 and 4×6 in different sizes (lengths). Traditionally, oak timbers were used, but we actually use pressure-treated lumber cut to length and have never broken any.” He adds that they’ve even used high-strength engineered (composite) lumber.

“We set up cribbing like pyramids – largest pieces at bottom, with subsequent layers becoming a solid base for the next,” says Nieves-Sosa.

Dustin Meyers
“We use lots of the new plastic mats,” says Dustin Meyers, owner of Timber Ridge Tree Care, a 21-year TCIA member company based in Comstock (near Kalamazoo), Michigan. “Mats go down for everything, especially in the fall. They’re needed on just about every job as dew points and temperatures drop and we get more rain and snow.

“We use lots of the new plastic mats,” says Dustin Meyers. “Mats go down for everything, especially in the fall.” Photo courtesy of Dustin Meyers.

Meyers’ outfit has 40 employees and runs 70 trucks, many outfitted with equipment from cranes to bucket trucks, “everything you can imagine.” He explains that mats aid in traction, but also in traveling across spongy soil and sod. He also instructs crews to use pads under outriggers.

“While it’s not mandatory to put pads under outriggers, sometimes the crews weren’t using them, and we once had an outrigger go through a septic tank no one knew was buried, not even the property owner. We have units with built-in pads, but the outriggers still can punch through the soil.”

That event resulted in a $60,000 expense to remediate the property and fix the machine, he reports, adding it was fortunate it did not result in injuries or a fatality. But, he warns, “This was a wake-up call and a reminder of the reason we need to put pads down. Accidents happen when you least expect them and when you get comfortable not using them (pads). It’s enticing not to use them because it saves time,” he continues, “but every time you don’t, there’s a good risk of a problem.”

Meyers observes how things have changed. “Twenty years ago, we used plywood as mats and pads. While the plastic ones are heavier, they don’t absorb water and don’t shred with use.”

Even so, he says, “You have to be careful of mats – all mats. With a 60-ton crane on a driveway, plastic can sometimes get slippery when backing up on a hill, so you have to be cautious,” he notes.

Jim Ward
Jim Ward, a 40-year veteran of the industry, is president of John B. Ward & Co. Inc., an accredited, 37-year TCIA member company based in Bryn Mawr, Pa., a trees-only company that runs three cranes – 33, 45 and 55 tons. The trucks that transport the cranes to the job sites all have racks capable of carrying mats and pads, 10 to 15 of each, he reports.

In this incident, the compact-lift outrigger punched through ground covering a septic tank. “This was a wake-up call and a reminder of the reason we need to put pads down,” says Dustin Meyers. Photo courtesy of Dustin Meyers.

“When we sell a job, we note what is needed to properly protect a client’s property. We have pickup trucks loaded with additional plastic mats and plywood. These trucks are dispatched as needed.”

Ward says they carry on board a mix of plastic and plywood, plywood especially for use on driveways, because the plastic products can mark up the surface, especially on hot days. Ward agrees that plastic can “scoot” from beneath the wheels and mar the macadam, given the molded-in diamond grips. His preferred method in that situation is 3/4-inch plywood, doubled up. “The machine weight and wood friction will hold them together, and it’s much better on the driveway,” he says.

“We use mats off the driveway and cribbing from the driveway to the lawn, so as not to crack the edge of the driveway (regardless of its composition),” Ward says. “Typically, we use four crew members on a job, plus the operator, so everyone hops on that part of the job and it goes pretty quickly.

“Once they get to where they’re going, they put one to two pads under each outrigger, but in most cases they will install 6-by-6-foot cribbing blocks comprised of 2- and 4-foot-long pieces. As they build up, they try not to go more than four blocks high to help prevent blocks from scooting out under load.”

Ward maintains that the rules for cranes and aerial lifts are similar; mats and pads are always a must. “You always run a risk, so it’s best to be cautious,” he says. Why? Ward warns that one has to be wary of things such as wet areas around lawn irrigation systems, as an example. “It’s easy to put down one mat or pad,” he says. And he stresses that, if nothing else, “It protects the lawn. We are always thinking of how to protect clients’ properties.”

Ward and his crews are not averse to going off road with cranes, he says, stressing, “way off road.” For that, he employs a product with a great name, a “swamp mat.” He explains that these are made of oak and look like a huge wood pallet. At 8 by 14 feet, they weigh just shy of 1,000 pounds each, Ward says. “We use them when we have to travel far off road and the crane will be down there a long time, coming and going on the mat. We bring them in with a big tag-along trailer and move them on-site with a loader,” he says. “We use the wooden ‘roadway’ to stage our chip truck and for the drive in (with) our log truck.”

Cribbing setup for a knuckleboom crane. “The team’s assessment on setup, and that includes installing matting, pads and cribbing, is critical to the stability of the crane,” says Dave O’Neill. Photo courtesy of Dave O’Neill and Noble Oak Safety and Training.

Dave O’Neill
Fresh back from helping with the cleanup in Georgia and North Carolina in the wake of Hurricane Helene is Dave O’Neill, CTSP and co-owner of High Canopy LLC, a tree care company located in Sewanee, Tennessee. He also is a trainer with Noble Oak Safety and Training, a five-year TCIA corporate member company based in Flemington, New Jersey, where he provides training on cranes, aerial lifts and other equipment. He had a lot to say on mats and pads, but the most important takeaway might be that you have to scout your job with scrutiny and plan the geometry and physics of what you’re doing.

He referenced some of his recent experiences witnessing washouts and erosion, especially in western North Carolina, where moving vehicles came dangerously close to disaster along washed-out roadsides. “I know folks still down there with cranes, taking trees off houses,” he says, adding that things like that (washouts) can happen on a job. “And it will be another month of that (taking trees off houses), and maybe a year to do the whole cleanup,” he observes.

“When hoisting with a climber using a crane, first and foremost be aware of how the risk increases dramatically,” O’Neill says. He instructs that tree care work is unique when compared with other crane work. “In general, with cranes and trees, the load begins at the furthest radius when it is received, usually with a climber right below the (cut) piece.”

So, according to O’Neill, the team’s assessment on setup, and that includes installing matting, pads and cribbing, is critical to the stability of the crane. “That starts long before getting the machine into place,” he maintains. That includes potential voids underground and begins with talks with the property owner or manager regarding septic, sewer and electrical services. Pipes and tubes underground can create voids that will not support the machine.

Sometimes it’s necessary to dig in the high-side outrigger to get to level,” says Peter Nieves-Sosa. Photo courtesy of Peter Nieves-Sosa, of The Crane Man Inc.

It becomes more important, he says, when the tree/machine load focuses ground pressure on one or two points.

Likewise, O’Neill says, “The crew has to be aware and prepare for recent driveway or other new construction that may not be fully settled. There also are property characteristics, such as whether it is dry or saturated with rain.” These all are factors, he says, in dealing with setup and use of mats, pads and cribbing.

There are formulas for setting up near obstacles such as foundations and stone walls. “Sometimes,” O’Neill states, “the only way to safely encroach on them is to increase the surface area to put the force down on, spreading the load with cribbing or stronger mats – even steel plate – for stability.

“One of the biggest issues in setup, then, is not thinking critically about any factor affecting the ground-bearing capacity,” he says.

With respect to aerial lifts, he says, “My philosophy is the same as for cranes. The loads may be less, but the stakes are the same. The main difference is that lifts can accommodate a lot of grade.”

Unfortunately, O’Neill says, while an aerial-lift outrigger has its “feet” on a ball joint designed to self-adjust a little bit on landing, users often do not take enough time to help leveling with pads or cribbing, or even digging to assist in leveling prep, thus stressing and causing premature wear of the ball joint.

Conclusion
Mats, pads and cribbing are a fact of life for crane and
aerial-lift workers, increasing operational efficiency and safety. But they don’t do any good sitting in a rack on the truck or crane. To do any good, crew members must be trained in their use and then encouraged to take the time to use them.

Rick Howland is a veteran newspaper reporter and editor, former national magazine owner and editor and retired international consultant in public relations, advertising, merchandising and training. He lives in the upper Hudson River Valley of New York.

Resources
TCIA’s Best Practices for Crane Use in Arboriculture – 4th Edition is a 180-page, fully illustrated reference with extensive information on matting, cribbing and much more. Find it online at tcia.org/shop, then type “crane” into the search box.