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Q: How can air tools be integrated into my company's existing plant health care program?

Q&A: Expert insight regarding your tree health care questions

By Shawn Bernick

Q: How can air tools be integrated into my company’s existing plant health care program?

— Matt Olsen, Olsen’s Arbor Care, Rhinelander, Wis.


A: This question and similar questions related to how companies should price and market services that use supersonic air tools are common inquiries for our technical support department within our company. Pneumatic soil excavation is generally referred to as “air-spading” after the popular brand “AIR-SPADE,” but the term is often used to encompass all air excavation work regardless of the brand used. Interestingly, our company receives more questions related to the business aspects of air tools and how the value of these services can be marketed to clients versus technical questions related to how pneumatic tools can be used, when they should be employed, or if they will damage tree roots.

Back in the early 1990s, before supersonic air tools became a widely accepted method of removing and mitigating soil, any type of root collar excavation required hand digging <dash> which could be a challenge if you were dealing with a tree planted several feet too deep. Hand digging often resulted in minor trunk and root damage from shovels and trowels inevitably striking the bark surface. Root collar exams were laborious, time consuming, and often revealed a limited picture of the issue due to the labor-intensive process involved in uncovering the collar. If a soil was compacted, there was very little that could be done. Vertical mulching — the process of drilling a series of holes within the drip line of the tree with an auger, and back filling with organic matter — was about the only option arborists had to combat compaction. This method only impacted a small percentage of the total root zone and, as with the hand digging methods, was very labor intensive. The augers required two people to operate, which added to the labor cost of vertical mulching. Root flare excavations to prepare trees for macro-infusion treatments with fungicides or micro-nutrients were also labor intensive and required careful digging at the base of the tree.

In short, prior to the advent of air tool uses for arboriculture, practices performed on soils were done by tree health practitioners at great effort and marginal effectiveness. Air excavation equipment has been around for a while in other applications such as construction and the underground utility industry, and during the last decade these tools have become more commonly used in the tree care industry. In addition to the uses for root collar examinations, root flare excavations, and soil compaction alleviation mentioned above, arborists have found an endless number of uses for air excavation equipment. They can be used to integrate organic matter or mycorrhizal inoculants into the soil, aerate the area around trees, and discover where roots are growing for the purpose of establishing adequate tree protection zones prior to construction. Chuck Lippi of Advanced Tree Care in Florida even used air excavation equipment to completely excavate a trench to replace a section of sewer pipe — all without severing the roots of a nearby mature live oak. The air tool, combined with a skilled backhoe operator, allowed this pipe to be replaced at less cost to the client than directional boring, and certainly in a manner less destructive to the tree than simply cutting off half of its root system. As you can see, the use of air excavation equipment in arboriculture can open up entirely new management options that would never have been possible before.

That brings us back to the question we started with: how can air tools be integrated into a plant health care program? The uses for arborists are established, and the benefits to trees have been documented in research publications and in field practice, but can they be profitable too? Many companies have developed flat rates for air excavation services such as root collar excavations and soil aeration. Often pricing for soil aeration is based on the area that will be excavated around the tree, which can range from a few feet beyond the trunk to beyond the dripline. In these cases, turf is removed around the tree using shovels or a sod kicker. An air tool is then used to mix and churn the soil 4 to 8 inches deep. At this point, additions such as organic matter or mycorrhizae can be incorporated, and then the surface is topped with an organic mulch layer. For more a la carte air excavation work, the pricing can follow the same per-man-hour schedule that some companies use for bidding pruning work. If the area to be excavated is known you can estimate the time required by using the formula of 1 cubic foot of soil per minute. For example, a 5-foot-diameter ring aerated to 6 inches deep contains a volume of just less than 10 cubic feet. At the rate of 1 cubic foot per minute it should take about 10 minutes with the air tool to aerate the 5-foot ring. Allowing 10 minutes for sod removal, 10 minutes for setup, and 20 minutes for mulching and clean up, it is easy to see how this small project could be accomplished in an hour from start to finish.

Air excavation work for the purpose of root enhancement, soil de-compaction or soil excavation can be done any time of year when the soil is not frozen. By opting to do majority of the work during the slower times of the fall season, you can utilize air tools to help extend the profitable length of the season. Scheduling several air excavation jobs on the same day can also help with operational efficiency, especially if you are renting an air compressor to get the job done. Renting air compressors for about $100 per day is a cost-effective way to get started with air excavation work. As new compressors cost around $13,000 to $15,000, you can always rent to start off and buy one later with the profits from your air tool work.

With so many opportunities for use in arboriculture, integrating air excavation work into your current plant health care program can be an easy transition — either by adding new revenue streams or by saving time and labor on service you are already offering. Including air spade services in your business is a great move for the trees, your clients, and your bottom line.


Shawn Bernick is director of research and technical support at Rainbow Treecare Scientific Advancements, Minnetonka, Minn. He will be answering one tree health care question in each issue of Arbor Age throughout 2010. To submit your question for consideration, please e-mail Arbor Age editor John Kmitta at jkmitta@m2media360.com Be sure to indicate that the question is for the tree health care Q&A, and include your name and contact information.

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