May 2024

Effects of long-term, repeated injections to treat ash trees for Emerald Ash Borer

Jake Miesbauer, PhD

The Morton Arboretum

Ever since the discovery of emerald ash borer (EAB, Agrilus planipennis) in the U.S. in 2002, it has devastated the ash tree population throughout much of North America. Trunk injections are one method that urban tree managers have for preventing tree mortality due to EAB, and they have proven to be highly effective. In particular, studies have shown that emamectin benzoate has a two-year efficacy in preventing EAB infestation. Early studies that investigated tree damage due to one to two cycles of injections found little evidence of internal damage. However, the frequency and severity of discoloration and decay given long-term, repeated stem injections and associated cambial wounding is not well understood.

For this study, we partnered with the City of Milwaukee, WI, who have an active ash tree management program and have been injecting their ash street trees since 2009. As part of their program they selectively remove and replace a small portion of their ~29,000 ash trees each year. Researchers selected 40 trees from the population of trees to be removed for analysis in this study. Tree trunks were harvested and delivered to The Morton Arboretum for dissection and analysis. We found little evidence of discoloration or decay caused by repeated injections (5-6 cycles over 10-12 years).

This is a positive development as it pertains to the long-term management of ash trees. The lack of any serious dysfunctional or decayed wood in this study can help to reassure urban tree managers that there is little to be concerned about with repeated injections over this time frame, given the injections are performed to the manufacturer’s specifications. Our plan is to conduct follow up research in 10 years to determine if these results still hold. 

Lead Donors

We are deeply grateful to the following people and organizations whose accumulated contributions to TREE Fund in 2024 surpassed $2,500 or more as of April:

Bandit Industries, Inc.

Bartlett Tree Experts

Lewis Tree Service

SavATree

Tree Care Industry Association (TCIA)

See the full list of lead donors who make our vital tree research and education work possible on our website.

TREE Fund Liaison Spotlight

Every ISA chapter recruits a volunteer to serve as their TREE Fund Liaison. These volunteers spend extra time attending meetings, spreading the word about TREE Fund happenings, events, and news, and often being the point person for TREE Fund fundraisers at their local chapters.

We'd like to highlight these wonderful volunteers and let you know a little more about them.

Rocky Mountain Liaison: Ben Rickenbacker

Forestry Operations Manager, City and County of Denver.

Third year as a TREE Fund Liaison.

Q: Why do you enjoy being an arborist?

A: I enjoy working with trees and sharing knowledge with others about the importance they have in our communities and the many benefits they provide.  

Q: Why did you choose to be the liaison for your chapter?

A: I wanted to represent the Rocky Mountain Chapter and strengthen the relationship TREE Fund has with the ISA and our members. I have also recruited some Tour des Trees riders from our chapter that I am proud to call lifelong friends now. 

Q: Why do you feel the need to communicate TREE Fund’s mission and events to chapter members?

A: I truly believe that TREE Fund’s mission is very important to our industry as practices are constantly changing and we are learning new discoveries each day. It is very important to use this knowledge to help us be better stewards of our urban forest in a time when it needs us the most. 

Q: What would you like to learn more about in your field or what research would you like to see done?  

A: What is happening below ground. It seems like there are always more discoveries and information about tree roots and once you think you know something it changes.  

Q: Why is new research important to you?

A:  Keeps us relevant and on the cutting edge so we can care for the trees in the best manner possible. 

Ride With Us In New England! Tour des Trees 2024

Registration ends on July 30, so commit to riding today and get prepared for the 2024 Tour des Trees in New England.

Join your fellow tree enthusiasts for five days of riding, September 22 to 28, and join us in spreading the word about tree research and education. Our journey this year will start with a dinner at the Bartlett Arboretum and Gardens in Stamford, CT where we will celebrate ISA's 100th anniversary in the place where it all started.

We are very excited about the engagement opportunities that this region will afford us and we are looking forward to spreading our love of trees as we ride. See our website for the latest information.

Registration and information can be found at www.treefund.org/tourdestrees.

Can't join us in New England? Show your support for TREE Fund by registering for the Virtual Tour des Trees at home and completing your fitness goals on your own time. See website for details.

Informational Webinar- June 13 @ 3:30pm CT

Save the Date!

Want to know all about this year's Tour des Trees? Join us for an informational webinar where we'll go over all the logistics and route details you'll need for this year's Tour.

First time rider? This will be a great introduction for the ride.

Veteran rider? Always helps to have route info, right?

Curious about riding? Hop on and see what the ride is all about.

Add the Zoom link below to your calendar and join us!

https://us02web.zoom.us/j/87262875237

Be a Tour des Trees Sponsor and Show Your Support

As a nonprofit organization, we depend upon the generosity of our corporate sponsors and individual donors.

Tour des Trees sponsors have the ability to interact directly with riders and community members during the Tour and show that tree research is important to them.

If you or your company would like more information on becoming a TREE Fund or Tour des Trees sponsor, please contact Paul at pputman@treefund.org or Jonathan at jcain@treefund.org for more information or to see a sponsor kit. 

Free Webinar Series

Back again this year, TREE Fund is proud to partner with the Alabama Cooperative Extension System to bring you free education offerings.

Next Webinar

June 18, 2024. Noon CT.

Presenter: Dr. Christopher Halle

Presentation: Establishing a Western United States Integrated Vegetation Management Network: Initial Results, Ancillary Studies, and Lessons Learned

Registration will be available two weeks prior to the webinar. See our Webinar page for more information. https://treefund.org/webinars

TREE Fund’s 1-hour webinars are free and offer 1.0 CEU credit for live broadcasts from the International Society of Arboriculture and the Society of American Foresters. Registration and information will become available on our website approximately two weeks before each webinar date.

Upcoming Webinars (registration opens about two weeks prior)

• July 23, 2024. Jose Delpiano. Computer Vision for Hazard Tree Identification and Assessment
• October 8, 2024. Dr. Robert Fahey. Monitoring and Modeling Changes in Street Tree Communities Over Time.
• November 5, 2024. Dr. Greg Dahl. Tree Caused Outages – What we know and what we have learned.

Missed a webinar? Watch it anytime on our website.

CEU Credit for Recorded Webinar

TREE Fund offers ISA CEU credits for one recorded webinar: "Loading of a Tie-in Point While Climbing." If you missed this webinar, you can now watch the recording and earn ISA CEU credits by completing a 20 question quiz with 80% accuracy. Learn more on our website.

TREE Fund

Tree Research and Education Endowment Fund

1755 Park St. Suite #200, Naperville, IL 60563

(630) 369-8300

treefund@treefund.org

www.treefund.org

TREE Fund is a 501(c)3 nonprofit whose mission is to support scientific discovery and dissemination of new knowledge in the fields of arboriculture and urban forestry.

TREE Fund recently earned our 2024 Candid Platinum Seal of Transparency! Check out our nonprofit profile to keep up to date with our impact. https://www.guidestar.org/profile/shared/17bf1c65-c913-4096-8695-11f0dc3fa73f.

Keep this link handy, we want to make sure you always have the information you need to support our work with trust and confidence.