Research News

New Video Documents PhysFest 2 at the Holden Arboretum

In July 2018, Holden Forests & Gardens hosted PhysFest2, welcoming 60 scientists from universities around the country to the Holden Arboretum for a five-day program focused on three goals: using the Murch Canopy Walk and Kalberer Emergent Tower as tools to access the surrounding tree canopy; training early career scientists in advanced technological methods for investigating tree physiology, as well as climbing and traverse techniques for canopy access; and providing training in interpretation and opportunities to conduct public outreach for K-12 and adult audiences.

Over the course of the five-day event, the 60 attendees worked tirelessly from 9am to 9pm, conducting approximately 3,600 hours of scientific endeavor, including training, data collection and outreach. Several large datasets from the event are currently being analyzed, investigating questions about how factors like climate and infection by beech leaf disease impact leaf and wood function.

As part of the outreach efforts, scientists shared their work on social media, gave tours to K-12 students, wrote articles for Holden Forests & Gardens magazine’s winter issue and helped create the following video documenting their experience.

The event was funding primarily through a grant from the National Science Foundation, awarded to the program’s collaborator, Jesse Nippert of Kansas State University, along with funds contributed by HF&G. Corporate meeting sponsors included the Ecological Society of America, and PMS Instruments. Additional corporate sponsors donated time and expertise of their specialists, along with the use of equipment during the event: LiCor Biosciences sent two representatives and loaned five top-of-the-line devices for measurement of photosynthesis, while METER Corp. donated the time of an environmental monitoring specialist along with 10 state-of-the-art devices for monitoring climate and canopy-level productivity, and lastly, the Union of Concerned Scientists sponsored a representative to teach attendees about engaging with lawmakers and policy. Six university professors from various institutions also donated their time to teach physiology techniques, and Phoenix Experiential Designs, which designed the canopy walk and tower, was hired to conduct the climbing and traverse training.

Summer Intern Places Third in High School Science Fair – Nov 9, 2018

Adele Metres, summer intern at the Holden Arboretum

Adele Metres, summer intern at the Holden Arboretum, recently presented the results of her research at Hawken School’s STEMM Symposium, where she placed 3rd out of 50 students. She’ll now advance to represent Hawken at NEOSEF (Northeast Ohio’s regional science fair). Adele spent the summer in Katie Stuble’s lab exploring the impacts of global warming on the timing of germination of native and exo

tic plants common to Ohio’s old field habitats. This work is the first step to understanding how global climate change may begin to reshape the composition of Ohio’s plant communities.

New Paper on Mycorrhizal Fungi and Plants

Staff scientists David Burke and Juliana Medieros, along with former Holden intern Mary Kay Klenkar explore the importance of plant diversity in forest understory communities and how the mycorrhizal network can affect the growth and performance of wildflower seedlings. This work was recently published in the International Journal of Plant Sciences.


Burke DJ, Klenkar MK, Medeiros JS (2018) Mycorrhizal network connections, water reduction and neighboring plants species differentially impact seedling performance of two forest wildflowers. International Journal of Plant Sciences, 179(4):314–324. 2018.

Holden Welcomes New Graduate Student Alexa Wagner

Alexa Wagner

Alexa Wagner has joined the Research department as a Ph.D. student. Jointly hosted by Holden Forests & Gardens and Case Western Research University, Alexa will conduct research to help us better understand the ecology of the Arboretum’s natural areas. She is currently working with Holden staff in the Working Woods section of the arboretum, studying how forest thinning and management of non-native species can influence forest growth and biodiversity. Alexa is a Cleveland native with a degree in Zoology from Kent State University.


Norweb Fellow Sergio Sabat Bonilla – Off to Grad School

We recently said goodbye to Sergio Sabat Bonilla. Sergio spend a year with us as the Research Department’s Norweb Fellow, studying the legacies of past land use on soil biodiversity and ecosystem functioning. He’s off to graduate school at Georgia Southern University where he’ll study the ecology of aquatic insects.

Summer Research Internships – Currently Accepting Applications

The Research department is currently accepting applications for the summer internship program. During the 12-week program, interns will get hands-on research experience in fields ranging from plant physiology to community ecology. For more information and the application, see our internship website.

Holden, U. S. Forest Search Project Focuses On Ash Trees

One of 500 ash trees recently planted at the Arboretum.

Since emerald ash borers were first discovered in Michigan in 2002, the insect has spread to 18 states killing more than 25 million ash trees, according to the U. S. National Arboretum.

Holden Forests & Gardens is working with the U. S. Forest Service on a project that will help identify ash trees that are better able to defend themselves against the insect and can be used in future reforestation efforts. Earlier this month, 500 ash trees were planted at the Arboretum as part of this project.

The 500 trees include plants propagated from ash trees, identified in natural forests in southeastern Michigan and northwestern Ohio, which have survived long-term EAB infestations that killed 99 percent of the other ash trees in the stand, as well as ash trees that are known to be fully susceptible to EAB for comparison. Researchers will monitor how well the selected survivor trees do against the insects.

David Carey of the U. S. Forest Service said that trees that are found to have the best defenses against the insect can be cross bred to create trees with even better defenses.  Trees that don’t do well in the planting will be removed, and the remaining survivors will breed with one another, producing seed that researchers are hopeful will be good enough at resisting highly damaging levels of EAB infestation to be used in restoration plantings.

This is part of an ongoing effort to study the “eternal external threats facing our forests,” said Roger Gettig, Holden’s director of horticulture and conservation. “New diseases and invasive species continually pose new threats.”

This is not the first collaboration between researchers from Holden and the U.S. Forest Service. A previous study looked at beech trees that are resistant to beech bark disease. Trees identified as resistant during that study were used to plant a seed orchard of beech trees at the Arboretum, which also will be used in reforestation projects. These types of collaborations are increasingly important. While invasive pests and pathogens have been around for a long time, combined with the stresses placed on our forests, including pollution and forest fragmentation due to human development, they are becoming a greater threat, said David Burke, chairman of Holden’s research department.

Public/private partnerships such as Holden’s work with the U.S. Forest Service is part of the solution to those threats. “We have some resources that can help the Forest Service – our land, our expertise,” Burke said, “We’re doing similar work and these partnerships allow us to do more than we would have been able to do independently.”

Research Welcomes a New Crop of Summer Interns

This May, Research welcomed it’s latest batch of summer interns. Interns will be conducting research alongside Holden’s scientists into topics ranging from ant-mediated seed dispersal in Holden’s forests, to urban reforestation, the microbiology of forest soils, and the physiology of horticultural plants. You’ll be able to see the results of their research on August 2, 2017 when they present their findings at our annual research symposium to be held at the Cleveland Botanical Garden.

From left to right: Sergio Sabat Bonilla, Jessica Langguth, Madison Proctor, Rachel Reeb, Andrea Maxwell, and Kyra Flauhaus.

March For Science

On April 22, Holden Forests & Gardens employees and volunteers took part in the March for Science Cleveland, demonstrating our commitment to science and support for the scientific community.

Several thousand people attended the rally in support of science. Our President and CEO Paul Abbey had the opportunity to address the crowd and re-emphasize Holden Forests and Gardens commitment to research and education.

“Data-driven science guides everything we do, from how we manage our natural areas, to the educational classes we offer, to the work we do in the community,” Abbey said. “Between our two campuses, we offer more than 500 nature-based and science-based programs for adults and children each year, with the goal of creating an army of environmental stewards that will help preserve our natural world for future generations.”

The Holden Arboretum has been conducting scientific research for more than 25 years, making significant contributions to the scientific understanding of man’s impact on forests and natural ecosystems, which have resulted in improved management and protection of our native forests.

Holden also plays an active role in training the next generation of scientists and environmental stewards. Workshops for middle school and high school students are held each year to pique their interest in plant-based science and internship opportunities give undergraduate the opportunity to work in the living laboratory of Holden’s gardens and forests.

Learn what you can do next to support science in your community.  

Holden Ants Help Us Understand Evolutionary Responses to Warmer Urban Climates.

When scientists think about how plants and animals will cope with warmer temperatures from global climate change, they typically study species in their native habitats. But with an increasing prevalence of urban environments across the globe, one group of scientists at Case Western Reserve University decided to use the hustle-bustle of Cleveland to their advantage. Cities are typically a few degrees warmer than the surrounding rural environments, making them great proxies for studying how quickly organisms could adapt to higher temperatures brought on by global climate change.

Dr. Sarah Diamond and colleagues used the acorn ant—a species whose colony can consist of over 200 individuals within a single acorn—to examine evolution on a compressed timescale. The researchers collected colonies within the city from the CWRU campus and the Cleveland Botanical Garden, and from rural areas outside the city including the Holden Arboretum and Squire Valleevue Farm. To distinguish short-term acclimation from evolutionary change, ant colonies from both habitats were held for 10 weeks at warmer or colder rearing environments and were then examined for changes in thermal physiology. The researchers found that ants held at warmer laboratory temperatures were able to tolerate higher temperatures than those held at colder laboratory temperatures, but also that ants from urban environments were able to tolerate warmer temperatures than their rural counterparts, regardless of what temperature regime they were held at in the laboratory. So in the short timeframe of 10 weeks, this species of ant showed an acclimation response, but more importantly, with just 100 years of urban warming, ants showed evidence of rapid evolutionary change. While a certain degree of flexibility may aid in dealing with short-term temperature changes, many studies suggest that acclimation responses won’t be sufficient for dealing with climate change in the long run. Luckily, some species—like the acorn ant—may be able to evolve quickly enough to deal with such changes.

For more information take a look at this NY Times article or the scientific article in the Biological Journal of the Linnean Society.

What are dominance hierarchies and how are they used in ant community ecology?

Ant communities have long been thought to be structured by competition. That is to say that what ants are present, and how common they are in our forests, is determined at least in part by competition for food and nest sites. For decades scientists have studied these dynamics by creating dominance hierarchies; basically ranking ant species based on their ability to win fights or defend food resources. A new paper by staff scientist, Katie Stuble, examines how dominance hierarchies have been used over the past six decades and how these rankings relate to various aspects of ant biology including the ability of ants to gather food and their relative abundance in an ecosystem. Findings suggest that these dominance hierarchies tend to be wildly inconsistent across space and time. Collapsing complicated networks of interactions into neat linear relationships seems to be inadequate in representing real world interactions. Further, the past obsession with aggression among ant species seems to miss other more nuanced traits that can help ant species succeed, including persistence, or even the ability to be sneaky and avoid conflict. For more information, see the paper in Myrmecological News:
Stuble KL, I Jurić, X Cerdá, NJ Sanders (2017) Dominance hierarchies are a dominant paradigm in ant ecology, but should they be? And what is a dominance hierarchy, anyway? Myrmecological News 24: 71-81.

Arboretum Celebrates 25 Years of Research, Renames Science Facility

The Holden Arboretum celebrated the 25th anniversary of its research building with a ceremony rename the facility that houses the research program the Ellen Corning Long and T. Dixon Long Center for Plant and Environmental Science. Both T. Dixon Long and his late wife, Ellen Corning Long, were long-time supporters of the Arboretum and its research program. T. Dixon Long was a member of the Arboretum’s board of directors from 1971 until 2003, serving as board president from 1982 until 1991. He is credited with leading the board through its most turbulent years from 1982 until the maturation of the Holden Trust in 1988 an played a large role in the creation of the science facility at Holden.

His wife’s connection with the Arboretum began when her family built Lantern Court in the 1930s, and her parents, Warren H. and Maud Corning, took an interest in the arboretum. Corning served as the Arboretum’s director on a volunteer basis, helping the Arboretum acquire new property and grow in its early years. Corning Long’s work as an educator, biologist and botanist is honored by the research departments dedication to environmental sciences, as well as the scientists commitment to wringing with interns.

Learn more about the research projects taking place at the Arboretum.

Pictured are Ali Long, T. Dixon Long, Sam Long, Clem Hamilton and David Burke.

Holden Scientists awarded funds to organize international conference on plant water transport.

A proposal for a new conference on multi-scale plant vascular biology submitted by Arboretum scientist Juliana Medeiros (conference co-chairperson) and collaborators William Pickman (conference chairman, University of New Mexico) and Barbara Lachenbruch (conference vice-chairperson, Oregon State University) has been accepted as a Gordon Research Conference-sponsored meeting. Gordan Research Conferences (GRC) is a non-profit organization dedicated to providing support for international conferences that cover topics on the frontiers of research in the biological, chemical and physical sciences. GRC meetings are small, fewer than 200 people, but they cover very specific subfields of research and are considered premier conferences for networking and collaboration. Proposals for new conferences are highly competitive, and the GRC Board of Trustees approves only a few new conferences each year. The conference will bring together scientists working at all scales of plant water transport research. The meeting will take place in the summer of 2016 and pending positive outcomes of the conference, it may be promoted to an official biannual Gordan Research Conference. Advances in plant water transport are of critical importance for understanding how plants may respond to global climate change.