Trunk Treatment: Macro or Micro?

From Dutch elm disease to the emerald ash borer, ­tree care professionals seek treatments for a variety of formidable ailments. But battling diseases and pests forces arborists and landscapers to juggle the pros and cons of adding on macro- and micro-injection services. Many believe injection systems can be an effective and potentially profitable service for landscape businesses to offer clients. On the other hand, these treatment technologies also necessitate an invasive process, such as drilling into the perimeter of tree trunks or root flare, which can permanently damage tree tissue.

When evaluating whether to add injection systems to your tool chest, experts say it’s critical to take the big picture into consideration. Deciding which treatment systems to offer involves broader business decisions such as charting how to increase returns on investments and providing customers with the best method for given conditions.

Joel Spies of St. Louis Park, Minn.-based Rainbow Treecare’s scientific advancement team makes a solid case for not jumping into either macro- or micro-injection services without first assessing the availability of a distributor, confirming which technology and products are most effective for regional tree ailments and weighing the environmental impact of each method. Practitioners will be most profitable and successful in offering injection services if they thoroughly do their homework.

Consider All Methods

There are multiple types of therapeutic interventions possible for controlling diseases and pests. Macro- and micro-injection are becoming increasingly popular because they offer reduced drift and require a smaller amount of active ingredient than traditional methods such as spraying. However, researchers and industry representatives alike emphasize that while injection technologies are advancing, they should not be used as a first line of defense. Bal Rao, manager of research and technical services for the Davey Tree Company, says that there is “the good, the bad and the ugly” of injection if it is not performed properly. Drilling can impact the cambial zone of a tree so that it can not effectively transport chemicals to the xylem. Without proper investigation of a tree’s symptoms, appropriate use of chemicals, and correct injection methods, there can be hazardous, costly consequences such as environmental contamination and loss of trees.

Considering such environmental and safety factors, Rao ranked four preferable treatment methods. Recognizing that there are variable levels of effectiveness per given ailment and tree, his first recommended route is using soil application, which is simpler and safer than spraying. Rao says his second preferred method is applying a bark penetrate which requires no wounding. Third, Rao recommends performing conventional spraying even though it may have non-target drift. And finally, Rao says he would use injection as a last choice because of the physical damage caused to a tree.

Practitioners need to consider the frequency of injections that are required for effective control and should also compare how many growing seasons potential treatments will last. The frequency of invasive treatments stresses tree systems and multiplies client costs. To help reduce these issues, applied research on injection technologies is currently underway at the Davey Institute for both in-house purposes and for primary injection producers such as DuPont. Ultimately, making injection technologies that are as effective, economical, user-friendly and as non-damaging as possible makes the best business sense.

“All types of tree injection involve wounding the tree, and this is a primary drawback of the technique,” Spies says. “A lot of problems can be managed with soil treatments. The real difference between macro and micro is the amount of active ingredient and water needed to meet the treatment requirements.”

Understand the Technologies

Micro-injection systems were originally designed by Mauget, and the company remains an innovator in the field. Mauget representative Marianne Waindle says micro-injection uses a small volume of solvent to inject the active ingredient, typically just one to seven milliliters per injection site. The equipment required for providing micro-injection services is typically a drill, injection gun and other small devices. Waindle says startup costs are a few hundred dollars, which many businesses can recoup within days. She also adds that injection is “where the future of tree-treatment is going” because it has less drift than traditional methods, is efficient and uses a smaller amount of chemical.

There are two different methods of micro-injection systems – low-pressure and high-pressure. The passive low-pressure system is the industry’s earliest injection technology, which requires drilling into the tree trunk. Then, a product is inserted from a capsule into the tree at the sap stream rate. The downside of this passive process is that the injection can take up to several hours and practitioners are required to stay on site throughout this time, thereby adding labor costs. Once the process is completed, the capsule must be removed and disposed. The drilling process does affect a tree’s ability to move water and nutrients. Damage can be cause by the solvents, which may include alcohol. Moreover, trunk wounds are difficult to heal and can attract disease. Since the active ingredients in micro-injection are inherently more concentrated than macro-injection, this may cause a greater potential for danger if there is breakage.

Applying Micro-Injection Treatment

Newer high-pressure micro-injection methods do not involve drilling. Most are more like a shot, which uses a syringe for pressurized chemical injection from the capsule. It requires no drills, power supply or bulky equipment.

“Research has shown that drilling upsets the vascular system of a tree,” says Arbor Systems consultant Elizabeth Nelson
 
Treatment without drilling enables the chemical to go immediately into the tree. To reduce chemical and labor costs, one state-of-the-art high-pressure technology to consider is Arbor Systems’ direct-inject, quick-connect system, which is an advancement on their Wedgle direct-injection device. This system uses a limited amount of active ingredients that are injected directly into the cambial zone. The syringe injection minimizes wounding to keep out fungi and insects and also prevents air from entering the tree’s vascular system, which cuts off flow. In addition to requiring no drilling, no labor time is devoted to waiting for completion of the chemical uptake process, thereby reducing costs and increasing efficiency. The high-pressure system’s minimal invasion also allows multiple or annual treatments with less tree damage. While many micro-injection capsules are prepackaged and immediately ready to use for on-site efficiency, Waindle says the micro-injection industry is moving from prepackaged, proprietary capsules to reloadable capsules that are open to use with products from multiple companies.

Like micro-injection, macro-injection methods offer less drift and require less chemical use than traditional treatments. A primary difference between the two is that macro-injection requires a large volume of water and uses a larger pressure system for quick injection of the diluted active ingredient. Since the active ingredient is less concentrated, it causes less danger to the tree system. Once holes are drilled and the system is set up, the solution is sent directly into water conducting tissues of the root flares for faster uptake and even distribution throughout the canopy.
 
Macro-injection is a bit more costly start-up service, ranging from $600 to $1000. Yet this investment is less expensive than adding-on many other landscaping services. It may also be considered more cumbersome because of its equipment, which includes a pump, tubing, reservoir tank, drill and infusion tees. However, macro-injection equipment is reusable. It does not require collecting used product syringes or capsules for disposal. Environmentally-conscious solutions are increasingly important to many clients, and Spies says macro-injection systems may be viewed as even more environmentally-friendly than micro-injection’s reloadable technologies.
Currently, Rainbow Treecare is the only distributor of macro-injection equipment. Rainbow’s system is designed to accommodate both their proprietary formulas and those of other suppliers.

While the best treatment method for each ailment and tree should be evaluated, both micro- and macro-injection systems offer practitioners and clients positive factors. In an open letter to tree care professionals, Arbor Systems president Chip Doolittle referenced the medical doctors’ oath to “First, do no harm.” This guiding mantra is leading the research and development of all new tree injection technologies.

Build Profit

Two key components affecting a practitioner’s injection service profits are how many chemicals are needed for an effective application and how much time is required per injection, says Arbor Systems consultant Elizabeth Nelson. These factors are important when establishing pricing and projecting work. Micro-injection processes (both low- and high-pressure) and macro-injection processes have labor requirements that can vary from minutes to hours per tree. Furthermore, the amount of chemical used and cost of the product varies greatly by ailment, active ingredient and type of injection. There are general rules of thumb for how closely injections should be placed and measuring tree perimeters to assess the potential number of injections can help in forecasting project costs. Thus, practitioners can develop a general calculation for estimating fees on injection services, yet this will evolve with experience using the systems and understanding the variables. Growing expertise in applying injections will increase practitioner efficiency and profits.

Overhead costs and market conditions will also impact the profitability of including macro-or micro-injection on your business’ menu of services. Overhead includes training, equipment maintenance and marketing. The marketing of injection services can take different routes from word-of-mouth to glossy informational brochures. Some clients prefer to have a single contractor on site providing landscaping services (being a one-stop shop for everything from mowing to tree healthcare can be quite a selling point).

Alternatively, when a practitioner is on client property or making a bid, presenting injection services can be done in conjunction with offering warranties on plants.

Arborists and landscaping professionals can start on their road toward a profitable business in macro- or micro-injection by researching which technologies and products are most effective for the common diseases and pests found in their region. Investing in training and equipment are the limited startup costs for adding on such services. In the long run, a practitioner’s in-depth knowledge of regional tree ailments and professional experience applying injection treatments will support labor efficiency, accurate fees and customer satisfaction.