Saving Time and Root Systems

Air excavators come to the rescue to loosen compact soil and safeguard the health of trees

There are times when the typical tools used to work around trees and dig up dirt just won’t cut it. In these cases, an air excavator can be just what you need when you’re working with compacted soil, a complex root system, or need to get extra nutrients into the ground without damaging delicate systems.

Air Excavation tools aren’t just used by arborists. Utility companies started using them in the 1980s to excavate buried objects such as utility lines and cables without damaging them. The military also used them to uncover landmines and unexploded ordinances, according to Pat Landers, market development manager for AirSpade, a manufacturer of air-powered soil excavation tools.

“Applications within the arboricultural and landscaping fields began to emerge as tree service companies recognized the advantages of this non-impact, non-destructive methodology for tree care-related excavation,” says Landers.

Today, tree care companies regularly employ air excavators to save time and tend to the needs of trees. While these relatively low-maintenance tools are mainly used to loosen soil, they can also be used to solve other plant health care issues.

Minimal Invasion

Arborilogical, a tree service care company based in the Dallas-Fort Worth, Texas, area, regularly uses air excavators in its work.

“We started using an air excavator shortly after the tool was introduced to remove soil from roots and root collars with minimal impact,” explains    Arborilogical owner Steve Houser.

The decompaction an air excavator provides can be used to keep trees healthy or to intervene before trees become too sick or damaged.

“The roots need air, and they can suffocate if there’s no pore space or it’s too difficult for water to remain in the soil,” says Kevin Brewer, the northeast territory technical manager for Arborjet, Inc., which manufacturers air excavators and injectable tree solutions. “Decompacting it goes a long way.”

Air excavators can replace tools with sharp edges such as picks, digging blades, shovels, or backhoes that can damage the tree during excavation. Air excavation also makes it easier to break up compacted soil with less fatigue to workers than other hand tools.

“Removing soil from roots and trunks using hand tools often takes more time and may cause damage if it is not done carefully,” Houser says.

It’s All in the Soil

When it comes to air excavators, it’s important to consider what types of soil you’ll be working with. Rocky soils, for example, make it difficult to excavate with a shovel, while compacted soil can be harder to get through.

“There are four types of soil in North Texas, and the time required to remove soil from roots or trunks can vary    according to the soil type,” says Houser.

Soil type can also affect the type of air excavator being used.

Arborjet’s Supersonic Air Knife, for example, has an option that allows arborists to add water to an air excavator, according to Brewer.

“If you have really dry compacted clay soil or heavy soil, air alone doesn’t break that up well, so adding some water to it helps break up that dry clay soil,” he says.

Another advantage to air excavators is that they allow arborists to add insecticides and pesticides to the tree’s soil to help it stay healthy.

Arborjet has provided solutions for pest infestation and disease for the past 20 years and has seen urban forests invaded by insects. The company’s Supersonic Air Knife can get needed chemistries into the soil to provide preventive care for trees and lessen the environmental impact.

“Increasing tree health to limit pest presence is one of the easiest ways to do that,” Brewer says. “It can lower that chemical imprint but still have a permanent effect on the tree.”

Compressed Air is the Key

One of the most important pieces of equipment when operating an air excavator is an air compressor. An AirSpade, for example, usually requires a tow-behind air compressor to utilize the tool, Landers says.

Arborists who use air excavators may want to consider different options, depending on the type of air excavator they’re using or the work it’s intended for. The cubic feet of air per minute (cfm) of an air compressor often depends on the site being worked.

The most popular tow-behind air compressors are rated at 185 cfm, according to Landers. Arborists working at larger job sites, or where more air flow is required to run multiple tools, may prefer 375 cfm compressors.

Arborists will also want to consider whether to rent compressors on an as-needed basis or commit to buying one. Equipment rental companies may offer enticing discounts if compressors are used for multiple days of work.

If you own a compressor, maintenance can also be an issue.

“The compressor requires normal engine maintenance and tire replacement,” says Houser, who owns several air compressors. “The air supply lines must be replaced over time.”

An air excavator, on the other hand, doesn’t require much maintenance, making it an affordable option for arborists.

“They’re pretty rugged and don’t have a lot of issues,” Brewer says. “They’re very well designed, they’re very low maintenance, and they’re very low wear.”

Other Uses

Air excavators aren’t just for trees. In fact, they can be useful in tending to other plant health care needs.

One issue an air excavator can help with is invasive species mitigation. Porcelain vine, for example, can climb into trees, reaching up to 20 feet in height.

“You can excavate out the underground nodules to get those out earlier and get the whole plant out because they regenerate from the roots,” Brewer explains.

Air excavators are regularly employed by utility companies, the oil and gas industry, agriculture companies, and even search and rescue operations.

AirSpade is popular with utilities that use it for trenching, according to Landers, while Brewer’s Arborjet offers specific tips for safely using its air excavators around electric and natural gas lines.

Construction companies also find uses for air excavators on job sites, including bringing in arborists to help excavate tree roots during the construction process.

“It’s just a good high-compressed air that can break up any compacted stuff,” Brewer says.