Grading and Excavation Contractor

Comment On This

Create A Link
To This Article
On Your Website

Heavy-duty attachments take on bark with bite in tough land-clearing applications.

By Carol Wasson

Land clearing is a brutal business. Nothing chews up equipment like a steady diet of dust, relentless off-road pounding, and a red-hot hydraulic system. Felling trees, cutting brush, or grinding stumps typically requires a significant investment in dedicated machines—or in a variety of specialized attachments mounted on just the right carrier machine. Certainly that’s why many excavation contractors subcontract clearing work to the forestry specialists. But there are also many who take on clearing and cutting tasks by combining the latest attachment offerings with an existing carrier in the fleet. As long as the latter choice is approached with logic, safety, scheduled maintenance, proper training, and realistic expectations, the outcome may be surprisingly efficient.

The Carrying Charge
Obviously, the optimum choice of carrier machines for land-clearing attachments is important in achieving production capacity goals. Experts agree that no one carrier does everything well, so pick the machine that is best suited to the majority of your given applications.

According to Caterpillar, many land-clearing attachments are classified as hydro-mechanical work tools, which are powered by the machine’s auxiliary hydraulics. Alternatively, fabricated work tools, such as buckets or forks, do not require additional hydraulics to operate. Therefore, many equipment manufacturers will recommend that hydro-mechanical attachments be mounted on a machine from the same manufacturer. They maintain that when hydraulic hose hookups and fittings are of the same strength and brand, this ensures a proper match and a tighter fit to reduce leaks and loss of pressure. Machines and attachments are designed to work as a system, and these pairings are intended to maximize the horsepower and hydraulic capabilities.

Choosing attachments that can be operated by multiple machines may enhance flexibility and productivity on the job site, says Caterpillar. Two machines with similar hydraulic flow and horsepower, such as a large skid-steer loader and a small wheel-loader, can usually run most of the same hydro-mechanical work tools.

Caterpillar stresses that generally a machine with high-flow hydraulics can operate attachments designed for standard-flow machines, but the reverse pairing (high-flow tools with a standard-flow machine) is not recommended, as its hydraulic system will be unable to supply the flow needed to properly operate the tool.

Chief Executive Officer Rick Shinn of Shinn Systems says that auxiliary power systems are required for high-production grinding. “Excavator-powered cutting attachments should only be chosen for light brush or small trees. Generally speaking, a 200-size excavator is the smallest size that should be chosen for fixed-tooth cutters, for example. This stems from the fact that excavators as large as 300-size machines only have 200 to 250 horsepower,” says Shinn, who explains that grinding with excavators (unlike using jackhammer-type attachments) requires constant movement in order to feed material into the cutter head.

“If you are not moving, you are not grinding wood. As you feed large material into the cutter head, it will slow. If you want to get the cutter head to speed back up, you will need to move the head,” he says. As production with any grinding system is directly linked to horsepower,

Shinn points to the fact that horsepower is what keeps the cutter head going, and horsepower is what reaccelerates the head so you can grind again. “The more horsepower that you have, the more wood you can process in a given time,” he says.

Shinn also addresses what he says is one of the biggest myths being spread today about attachments: that two motors are better than one. “One large hydraulic motor will produce exactly the same torque and horsepower as two small motors half the size,” he says. “This is because torque is a function of displacement and pressure. Two motors also present a unique situation when driving a common shaft. If one belt breaks, the oil will flow to the areas of least resistance. This would be the motor no longer connected to the cutter by the belt. In this instance, since all of the flow is going through this motor, its speed goes to two-times that of normal. If the motor is not rated for this speed, damage can occur quickly.”

Keeping Your Cool
“There aren’t too many smaller skid-steers that are designed for forestry applications. Most of them will suffer an overheating problem,” says Layton Holsinger, owner of Layton’s Tree Service in Huntersville, NC. He says he’s found a great equipment solution with the operation of a new Shinn Systems SKC-Series cutter head mounted on his ASV RC100 rubber-track skid-steer. “The attachment has an internal cooler that cools the oil while you’re operating it. It runs longer and harder than other units, and you don’t have to worry about your hydraulics overheating,” he says.

Shinn Systems says that the SKC-Series cutter head is the first skid-steer-mounted head with an optional built-in oil cooler to reduce hydraulic temperature. Using the airflow produced by the cutter head, air is drawn through the built-in cooler to cool the oil before it is sent back into the machine. This reduces operating temperatures and downtime due to overheating.

Photo: Bobcat

Bobcat's new forestry cutter attachment features 30 carbide cutting teeth for faster production.

Holsinger says that the new cutter head does twice as much as any of his other attachment units. “That’s due to both its cooler and its teeth,” he says.

“Using the most effective cutting teeth possible is critical when operating an attachment on compact equipment, since you want to make the most of the limited power you have available,” says Shinn. “You need to slice through wood, instead of pounding it with hammers or blunt-faced carbide.”

Totally Stumped
Stump removal can be the most difficult and time-consuming aspect of land clearing. However, stump-grinding attachments are able to grind the stump down below the surface of the soil, ensuring that the root system is killed and that no “suckers” can develop to produce a new tree stem. On many newer models, this below-the-surface grinding actually turns the root system into mulch.

“We operate a Rayco stump-grinding head mounted on a Cat 312C excavator,” says Greg Hoppel, president of The Brush Cutters, a land-clearing operation based in Cape Vincent, NY. “This equipment was very effective on a recent wind-farm construction project. There was a certain area where trees had to be cleared to allow the flow of wind to the windmill. The stumps needed to be removed so the property could be easily mowed. Grinding them in place was the best solution,” he says.

Hoppel says that many contractors will pull stumps out of the ground, dislodging a lot of dirt. The stumps will then be processed in a tub grinder, and the dirt must be either hauled off or filled back into the holes.

“We can come in with just one machine and a stump-grinding head. We simply grind the stump materials down, and we’re done. We don’t have to haul in a bunch of other equipment or haul out a lot of dirt and material,” he says. The company runs the attachment off the same auxiliary pack used to run its brush-cutting head.

Maine-based contractor Larry Mason uses an EZ-Stumper 280H manufactured by Skid Steer Solutions. Mason says he likes having a stump-grinder attachment on a skid-steer because it makes it very universal versus a trailer hitch–style stump grinder.

He used to remove stumps with a 40-horsepower excavator. It would take about a day to stump a 1-acre lot (approximately 35 stumps with 10-inch diameters). With the new attachment, he says, the same work can be done in just two hours and the chips reused to smooth the lot afterwards.

Resource Recovery
“We’ve been known as a company that provides ‘resource recovery’ equipment and attachments,” says Dennis Goldbach, vice president of operations for Fecon Inc. “Over the last decade, burning regulations have become far more prominent. Rather than simply burning material, contractors must do something with it—such as recovering the wood chips for boiler fuel or for ethanol production.”

Goldbach says that excavators generally tear out vegetation rather than mulching it. “But there are applications where mulching will make more sense than dozing it all down and making a pile that can’t be burned and must be hauled away. Using the right attachments will give excavators a better blend of services,” he says.

The Forest Preserve District of Kane County in Illinois uses a Fecon Bull Hog mulching attachment mounted on an ASV RC100 to clear non-native shrubs that impede the reproduction of valued oak trees.

The new equipment replaced the need for 12 chainsaw operators, who required a month to clean 20 acres of infested woodlands. With the mulching attachment and one operator, the district can now complete an acre per day.

The maneuverability of the skid-steer and localized shredding action of the cutter head allow selective thinning. The operator can remove materials within inches of the oaks without doing any damage to the trees.

Glenn Garrett of North Carolina–based Wetland and Woodlands Management does a lot of precision-type, low-impact environmental clearing, such as wetlands creation and habitat maintenance, as well as the selective removal of certain tree species. His Fecon Bull Hog cutter head is mounted on a fully amphibious Cat 311 excavator that actually crosses ditches and rivers, performing somewhat like a pontoon boat with tracks to pull the unit along.

The cutter head has fixed teeth, which engage the material to be ground. Ripping material through comblike counter cutters produces a mulched end product that is left on the ground to prevent soil erosion.

Fine Grinding and Grooming
Recently introduced by Loftness, the TimberAx is a hydraulic-drive tree and brush shredder attachment that creates a highly groomed area in just one pass. “The unit is particularly desirable in real estate development where owners want to leave the larger trees and simply remove the undergrowth that hinders them from surveying the site or showing its potential to a prospective buyer,” says Bill Schafer, engineering supervisor for Loftness.

Importantly, the TimberAx requires less power and delivers a far finer cut than carbide-type units due to a unique rotor design that uses reverse rotation. “This unit is the only one on the market that spins the opposite way, picking the tree off the ground and feeding it across the top of the drum between a shear bar and sharpened blades. Other units spin the rotor down in front, so as you address the trunk end of the tree you’re hitting it down into dirt, and then the dirt becomes an ‘anvil’ to work against,” says Schafer. “This means that you can never get the tree processed in one pass. You move forward along the length of the tree and then need to back up and regrind the material.”

Although the TimberAx can be utilized on up to 300-horsepower carriers, the attachment is most popular on compact skid-steers. “Using land-clearing attachments on compact carriers allows the larger equipment to work more effectively. The compact setups can take out all of the undergrowth and brush that hinders the big rigs while also enabling operations to replace hand crews and chain saws,” says Schafer.

A Safety Net
Regarding land-clearing and forestry attachments, one of the biggest issues is that of safety. “It’s important to assemble a comprehensive package that includes the carrier, the attachment, and the various guards and debris shields, which keep both the operator and the machine safe,” says Justin Odegaard, attachment product representative for Bobcat Co. He feels that safety issues have generally been lacking in this market. “There are attachment manufacturers and then there are machine manufacturers, and a lot of times they are not tied together at all. So contractors just put things together and run with them,” he says.

For 2007, Bobcat has released its new forestry cutter attachment package, which includes a forestry applications kit that can be installed on specific Bobcat loaders. Because Bobcat decided that safety had to be the paramount consideration, the loader must be equipped with the applications kit in order for the attachment to operate.

The kit includes a specially designed cab door (which features a front emergency exit) constructed of laminated polycarbonate. An electronically controlled valve ensures that the forestry door is installed on the loader before the attachment can be used. There are also safety guards to protect the operator and loader from falling tree limbs and debris. Other features help reduce the amount of debris that can accumulate in the machine. They include an ISO 3449, Level II, falling-object protective structure (FOPS); polycarbonate top and rear windows; lift-cylinder debris shields; headlight and taillight guards; a hydraulic quick-coupler guard; a radiator debris screen; a muffler guard; and a fire extinguisher.

Featuring a 60-inch cutting width, the forestry cutter attachment is designed with 30 carbide cutting teeth for faster production. Its tube-style drum and spiral-tooth pattern allow one tooth to engage at a time. Operation is smooth, and less horsepower is required to do the job, according to the company.

The Last Words on Maintenance
Yes, land clearing is indeed brutally tough on equipment. So it’s fitting that some final words be spent on maintenance. You can glean some great tips on the latter, as well as peruse various forestry horror stories by searching through a few contractor Internet forums and chat sites. Here are some standout comments from cyberspace:

“Cooling is a major concern, and the best advice I can give anyone in the mulching business is to buy a cheap gas-powered leaf blower and make it a habit to blow the machines out every time you stop.”
“Having a good dealership nearby is essential, and a good service or parts guy is worth his weight in gold. My service manager has walked me through countless problems on the phone and has saved me thousands. On top of that, you need to locate a few good welding and hydraulic shops in your service area. I recently cracked a chrome rod on the hydraulic cylinder of my tree shear and had a hard time finding a shop to weld it up.”
“Before you buy a machine, check out the parts departments and compare prices on hydraulic couplers, hoses, and other common replacement items. Make sure the machine you purchase can live on a diet of cheap hydraulic oil. When a limb falls and breaks a coupler, you will see firsthand what 41 gallons per minute at 3,300 pounds per square inch looks like.”
“Check out your area’s rental outlets and see if they carry the same or similar machine and attachments you want to purchase. In the highly likely event that you need to take your machine in for service, it’s nice to know that you have a rental in stock that will allow you to finish your current job.”

Nothing can beat the wise words of those who eat, breathe, sleep, and live land clearing.

Carol Wasson owns JCL Marketing & Communications Inc.

GEC - Buyers Guide 2008

Back To Table
Of Contents