The authors of the newly published Tree Injection Best Management Practices guide discuss its importance
By Brandon M. Gallagher Watson
Best Management Practice guides (BMPs) are put out by nearly every industry to establish a consistent set of actions that become the professional standard. In the world of tree care, the standards are put out by the International Society of Arboriculture (ISA), and cover most of the major topics of our trade. Tree pruning, fertilization, managing trees during construction — even lightning protection systems — all have official BMPs available. Up until now, tree injection (the process of delivering treatments directly into the vascular systems of trees) has had no industry standard guidelines. Every “How-to” available was coming solely from the makers of the various injection devices, leading to some inconsistent, contradictory, or even downright ineffective management techniques.
Shawn Bernick, MS, the former director of research and current chief operating officer for Rainbow Treecare Scientific Advancements, and Dr. E. Thomas Smiley, plant pathologist and soil scientist with the Bartlett Tree Research Laboratories, were requested to co-author the ISA’s Tree Injection BMP. I recently sat down with them to discuss the origins and the importance of putting this guide together.
Q: What purpose did you see this guide serving?
Bernick: The intentions of the BMP were that, regardless of the device or tree injection equipment that you were using as an applicator, there are some common recommendations that will minimize any adverse affects of tree injection but will also help in the performance of the different products that are being applied out there. That was one impetus for it, and there were companies out there making recommendations about how it should be done, and there was not consensus among industry and scientists on that. There was confusion for technicians on how to do this, so we were trying to create some consistency and common ground where we could.
Smiley: We do focus on those generalities of where, when, and how to apply because those are some of the common issues we see in the industry. We see people trying to inject into tree trunks when they should be doing root flares — that’s a major one. We get a lot of questions about what time of day materials go up more quickly, so we tried to answer those common questions and point people in the right direction for doing tree injection.
Q: How did this Tree Injection BMP come about?
Smiley: This one came to us from the industry — specifically from Joel Spies at Rainbow — and I think his motivation here was seeing a lot of poor-quality tree injections, either ones that damaged trees or didn’t do what they were supposed to do, and he wanted to bring up the quality of the entire industry. And that’s one of the things that best management practices do, by providing information that is necessary or is useful to working arborists to guide how they do work. So, Joel really starting driving this, and started working with other manufacturers, and got all the major manufacturers on the team for writing and review.
Bernick: If I could add to that too, I think with the upsurge in tree injections over the last decade or so, going back to the early 2000s — with invasive species like hemlock woolly adelgid, emerald ash borer, and Asian longhorn beetle — there has been a lot of emphasis on the use of tree injection as one of the methods for managing those key pests. Over the last couple of years there have been a number of industry workshops focused on tree injection that have also increased the awareness and knowledge — and identified some of the missings as it related to tree injection — and one of those missings was to have a BMP that could give consistency and some guidance so everyone could get on the same page.
Q: What kind of peer-reviewed, published research were you able to pull from for this guide?
Smiley: There is certainly a lot of product-based research out there showing that this material works on this pest. There are a number of studies that date back to the Dutch elm disease years — in the ‘70s and ‘80s — that cover some of these more general topics; but, because of the age of that research, a lot of folks just don’t know about it. So we tried to put it together in a more readable form so they could find it more rapidly.
Bernick: As far as some of the data gaps that are still out there, it would relate to some of the comparative assessments of the different devices and how they may or may not cause adverse affects over longer periods of time, with repeated annual injections or injections performed every few years — those longer-term studies seem to be missing. I think the kind of things that are hard to study in a replicated trial are “what are the long-term impacts if these treatments are done correctly — using some of the practices laid out in the BMP?” and then, “what are the long-term impacts to the tree if done incorrectly?” That was one of the challenges putting the BMP together — taking information of the industry that there may not have been university or replicated research on, and then coming to a consensus on those industry recommendations for which we may not have a fully vetted research project. We just didn’t have published research to fall back on, so we had to rely on industry experience for many of these recommendations.
Smiley: That’s right, a lot of BMPs — whether this one or others — are based on what is done in the field, not necessarily what is known in the research. I think smart and opportunistic researchers can look at these BMPs and probably find at least a dozen opportunities for further research studies. Certainly, we do that here at the Bartlett Lab, where we are working on these BMPs we can see the voids. Sometimes it’s a quick experiment and sometimes it’s a longer experiment, but it can guide future research to answer some of these questions.
Q: What were some of the challenges to putting this guide together?
Bernick: Right off the bat, just defining some of the terms that were being used differently. For example, “injection” versus “infusion” and how they were being used differently in the industry. Coming to a consensus is what I like about the BMP, including the glossary of terms in the back. So as we are out training practitioners we can be using these terms to create a common language. Another challenge out of the gate was knowing that we wanted this document to stand the test of time — to not have to go back and revise it every year. So a challenge was “do we want to include the common active ingredients and trade names?” and while we felt that would be a benefit, it was probably outside what we were trying to accomplish with the BMP. It’s probably not what a BMP is intended to have, but it would be good to have that out there. We felt that got too into the commercial piece, and saw challenges from the device manufacturers and wanted to steer clear of that.
Smiley: Certainly there were challenges out there from the different injection products, all the different materials, and a lot of people doing the treatments in different ways. I think Shawn did a really god job of overcoming all of those.
Q: How often do documents like this get updated?
Smiley: It varies a bit based on the origin of the BMP. Most of our BMPs are based on the ANSI 300 standards, and there is a schedule for updating the ANSI A300s that is a five-year schedule. Once a new standard comes out, we review that standard with an eye on the BMP and then revise that BMP. With ones like Tree Injection, where we don’t start with an ANSI standard, we would try to stick pretty close to that five-year schedule, but it is not as rigorous. I think we will take a look to see if anything has changed that will substantially alter the recommendations in the BMP. Not every BMP needs to be updated every year, but certainly they need to be looked at every five years.
Q: Why do you think there is controversy surrounding tree injection wounding that we don’t see in other practices, such as pruning?
Smiley: I think some of that comes from the difference in anatomy, like if you are taking a branch and not cutting the trunk, we’ve got a pretty good natural defense system going on there. But we also have a pretty good defense system in the trunk and root flare — one of the reasons we like root flare injections more than the trunk injections is that most trees tend to be pretty good compartmentalizers in that root flare area.
I think the main reason [it can be controversial] is that it is seen as an option in many people’s minds. And we do mention that if you can spray or soil apply a treatment that you may be better off. We try to reserve tree injections for those cases where we just can’t get the efficacy with spray or soil treatments.
Bernick: I think, for me, it comes down to the techniques, whether pruning or drilling, if you are able to do them properly and well timed [they are beneficial]. We know with both of them if we do them too often or do them poorly they can be harmful.
Smiley: That’s right, and there haven’t been many long-term studies that have looked at this. We did some similar using drilling to detect decay in trees, and after five years the only site we found decay to spread is when penetrated into decayed wood — which we typically don’t do with tree injection. In our study, we did not find any decay spread in those relatively shallow [tree injection] holes.
Q: What are the topics you want readers to take away from this?
Bernick: A big distinction to get the industry aligned on, and Tom alluded to it earlier, is the importance of doing injections into the root flares versus higher up on the trunk — that’s an important one. Traveling the country [we see] a wide range in the way that companies do their applications, everywhere from up at eye level to down on the root flare to spiraling around the tree — all over. So getting root flare placement established was key.
Then, the importance of drilling is oftentimes overlooked. Having sharp drill bits; having nice, clean holes like a surgeon would do; and putting focus on those techniques. I think the devil is in the details on these things; so getting the industry on the same page is a huge contribution.
One distinction right away we wanted to get across is that tree injection is just one methodology one might use to manage insects, disease, or tree health issues; and what factors might lead you down the decision tree to using tree injection and that it has its pros and cons from a “tool in the toolbox” approach — I think that’s number one. Then, number two, as you make the decision to use tree injection, ensuring that you are following some of the guidance on the practices around root flares, drilling, injection site placement — some of the key distinctions that are in there regardless of the device you are using. Then, I think number three, I see an opportunity with the specifications — especially with the invasive species, emerald ash borer treatments that are going on with municipalities and government entities — to create a consistent approach to bidding the work and doing the work.
The Tree Injection Best Management Practices guide can be purchased through the ISA at http://www.isa-arbor.com/store/product.aspx?ProductID=2112&CID=117
Brandon Gallagher Watson is creative director at Rainbow Treecare Scientific Advancements.