There are symbiotic relationships across the natural world, with organisms counting on other organisms for success and survival. Symbiotic relationships also exist in the corporate environment, with one organization working with another organization for success and, in this case, tree survival. Such is the partnership between Bartlett Tree Experts, a scientific tree and shrub care company with local branches throughout the United States, Canada, the United Kingdom and Ireland; and Casey Trees, an organization that plants, cares for and protects trees in Washington, D.C.

The primary purpose of their collaboration is for Bartlett to provide scientific research and tree care geared toward the preservation and survival of urban trees in support of Casey Trees’ effort to increase the tree canopy in and around the nation’s capital.

Backdrop
Since its establishment, Washington, D.C., was always to be a city of trees. This vision dates to its initial design and to the country’s first President, George Washington. Washington was a tree lover and an accomplished horticulturist who, in tandem with the city’s designer, Pierre L’Enfant, proposed a lush tree canopy with ample green spaces and tree-lined boulevards for the nation’s new capital. But over centuries, the tree canopy began to decline. When a Washington Post article in November 1999 chronicled this decline, it set the course for the Casey/Bartlett relationship to blossom.

The Post article detailed that in 1950, the tree canopy in D.C. had approximately 50% coverage, and that it had dropped over time. It stated that in just the period from 1973 to 1999, the acreage of heavy tree cover declined by 64%. This alarming statistic prompted Betty Brown Casey, a longtime D.C. resident, to establish an urban-forestry nonprofit with a mission to “restore, enhance and protect the tree canopy of the nation’s capital.” Casey Trees was established in 2001 with the goal of reaffirming the city’s “City of Trees” moniker.

Mark Buscaino, executive director of Casey Trees, completes the story and expounds on the start of this collaboration. “In 2008, Mrs. Casey gifted to Casey Trees her former home and 700-acre horse farm – Springsbury Farm, now renamed Casey Tree Farm – in Berryville, Virginia,” explains Buscaino. “The purpose of the gift was to grow trees and to conduct tree research. Prior to this, Casey Trees purchased tree stock it used in its community tree plantings from third-party vendors and conducted research on a limited basis. The farm provided a way for Casey Trees to grow its own stock to meet its unique needs.”

Need for research
While Casey Trees conducted research over the years, the results were mixed, says Buscaino. “It became clear through our initial research trials that to conduct research in a successful and durable fashion, we needed a partner with deep experience in research and with a philosophy similar to that of Casey Trees, to share those research findings broadly.”

A natural fit, therefore, was Bartlett Tree Research Laboratories (BTRL), based in Charlotte, North Carolina, which had been doing tree research for decades. In 2018, both groups met at Casey Tree Farm to talk about the possibilities of a partnership to conduct research and pursue similar activities of mutual interest and benefit to both organizations. “We’ve been collaborating ever since,” says Buscaino.

Aligned missions
Kelby Fite, Ph.D., vice president and director of research at BTRL, details its similar purpose. “Our mission is to investigate new products and new techniques, and to better care for the urban shade-tree canopy. (We) have 45 staff involved in the scientific approach to tree care as well as in training, where the primary focus is to support the arborists in the field. The greatest benefit comes from associations with allied organizations like Casey Trees.”

Buscaino reiterates the depth of the relationship with Bartlett. “The Bartlett and Casey Trees relationship is indeed unique. Both partners are sharing a large parcel of land to not only conduct tree research, but also to conduct trainings and related activities that are of mutual interest and benefit – and, by extension, that provide benefit to the entire arboricultural industry.”

Early success
Vincent Drader, director of communications at Casey Trees, relays the success of Casey Trees’ programs thus far. “Since our inception in 2001, we’ve planted more than 60,000 trees, and we’re currently planting about 7,000 trees a year. Right now, the city is at 37% canopy, and our goal is to get to 40% by 2032.”

Transplanted trees are initially grown at the Casey Trees nursery for about two or three years, depending on the species. The facility grows between 40 and 50 individual species, and they are transplanted when the tree diameter is 1.5 to 2 inches. Trees in this diameter range are usually between 6 to 10 feet tall, and that helps increase the odds of success when planting in an urban setting.

Drader continues, “We always try to plant for environmental and ecological impact, so whenever we can, we plant the largest tree possible. We adhere to ‘right tree, right place’ planting principles, and plant trees that are going to have the most benefits for the surrounding community to make sure the tree will survive, thrive and grow to full maturity. Most of the transplanted trees are native to the area. Some examples of the larger tree species would be oaks, tuliptree and sycamore. And then smaller natives that can grow under power lines or other structures might be redbud or serviceberry. And some medium-size examples are birch and maples. All of these are hardy, urban trees that are going to do well.”

Trees as an asset – a key to symbiosis
With planted trees comes requisite tree care. A healthy tree is an asset both environmentally and socio-economically, and with Casey Trees providing trees that give Bartlett Tree Experts’ arborists the ability to care for those trees, a true double-positive symbiotic relationship exists.

Chris Riley, Ph.D., research scientist at BTRL, says, “A lot of the formal symbiosis comes from both organizations having a pronounced interest in tree-related research. This leads to discussions that create a research partnership and ways for further collaboration. We (Bartlett) have held trainings and meetings at the farm, we (Bartlett and Casey Trees) have implemented a tree-climbing training academy and we have tried to continue to explore connections between the growing and planting side of the industry and the long-term-care side.”

These two organizations work well together, and, with a common purpose guiding their actions, they’re both set up for success, and that means improvements in urban-tree survival and an improvement in the community in which the trees are planted.

Researching relevant issues
Even though their relationship fosters the routine care of trees, one of the main points of Bartlett and Casey Trees working together is the opportunity to do real-world testing and conduct research.

Dr. Riley comments, “There are a wide variety of trials and studies underway currently. We want to make our investigations yield information we could share not only with local audiences, but with the broader scientific community.”

Riley continues by documenting examples of a soil-amendment study. “In the past, the Casey Trees team has used a commercial amendment in planting holes with the goal of improving soil-water dynamics and planting outcomes. Being the skeptic I am, I asked if the material actually worked. That led to us (BTRL) developing a study in tandem with the Casey Trees field teams using different planting amendments and (seeing) how they influence tree establishment and survival. This was installed about a year ago, and we will begin to collect data on survival and growth this coming field season.

“Our current soil-amendment trials include five test groups: Trees planted with no soil amendment (our control group), trees planted with Zeba (a fine, biodegradable, starch-based polymer that is superabsorbent, to allow soil to hold more water), trees planted with Diehard (a commercial all-in-one transplant product), trees planted with biochar alone (a highly absorbent, charcoal-like substance that is produced when organic materials undergo pyrolysis), and trees planted with a mixture of biochar and compost.”

Riley also is looking into the effects of mulch-ring size on tree establishment and growth. “There is a lot of different guidance out there on how far out you should mulch around your tree, but not much data. I wanted to see if there was an optimal mulch-ring-radius size where benefits to tree health ceased accumulating. The results would be of use not only to Casey Trees on the planting side, but also to the tree care industry on the maintenance and plant-health-care side. Casey Trees donated 100 trees and the space at the farm, and both organizations have been carrying out the investigation.”

Per Drader, this study also involves trials on other mulching techniques in addition to radius. “We’re doing research trials right now on volcano mulching. It’s generally understood that when you plant a tree and volcano mulch it, which is piling the mulch up too high next to the trunk of the tree, over time it decreases the lifespan of the tree. But again, the empirical data on the effects of this practice are often lacking. Out of the 100 cherry and tulip poplars provided in our study, some are mulched correctly and some are mulched incorrectly. We’re excited to see what the data shows years from now.”

Environmental and socio-economic impact of healthy trees
While the teams await the results of on-going studies that can start a new tree on the road to urban success and survival from day one, other data demonstrates that healthy trees within an urban setting create many positive effects.

Drader relates, “Trees have an extremely positive economic impact on urban spaces. For residential areas, trees can reduce energy costs by providing shade to cool homes in the summer, as well as provide curb appeal that increases home values. It’s been proven that tree-lined business areas attract more shoppers, and that customers spend more time and money in green commercial zones. There are studies that say areas with trees tend to have less crime than areas with fewer trees.

“Cleaner air and reduced pollution mean reduced healthcare costs,” continues Drader. “There’s a correlation between lower asthma rates in areas where there are trees. Sequestered carbon and reduced urban heat mean slowing some of the impacts of climate change and reduced catastrophic weather events. Trees are truly our best solution to our current climate crisis, but their benefits go far beyond that, including physical and mental health and our general well-being.

“There is also the reduction of noise pollution,” Drader says. “Trees provide a vegetation buffer on the sides of streets or in people’s front yards, and if the trees weren’t there, you’d have all these sounds from buses and cars ricocheting off hard surfaces. Trees also help with traffic calming. If you drive down a street that has no trees close to the sides, you’re more likely to speed.”

Drader conveys the needs for trees in under-served urban areas, such as “Washington, D.C.’s wards 5, 7 and 8 in the east part of the city. Those are traditionally under-served areas, with higher poverty rates, higher asthma rates and vulnerability to extreme flooding events. So those are not only
under-served areas, but also areas that would see the greatest benefit from more trees and an increased tree canopy.”

Community and other organizational involvement
Realizing the potential benefits of trees to their neighborhoods, community members are a great resource. Drader comments, “We connect with thousands of volunteers every year at our community planting events and more. Communities, neighborhoods and partners all over D.C. are involved in myriad ways – planting, caring for and protecting our trees and green spaces.”

Drader continues, “Our organization’s activities within the community and the benefit we see, from a purely for-profit lens, is that it elevates the value of the asset, the tree. If you have nonprofits in cities really helping the public and community, putting value on the thing the private sector is caring for, then you also have people thinking about trees more, wanting to care for them, protect them and, in turn, raising the value of that asset. So, for the private sector, it just makes sure that the trees are present and a valued commodity in our local communities.”

Buscaino echoes these sentiments and acknowledges the help of other outside organizations. “The Casey Tree Farm is always open to supporting efforts of organizations working within the green industry. We’ve hosted dozens of seminars and events with local nonprofits, municipalities and others in the tree space, including the ISA (International Society of Arboriculture). As exposure grows, we hope to do more, and are eager to create new linkages to help others keep their communities as green and tree canopied as possible.”

Workforce development and collaborative training
Although the original aims of the Casey Trees/Bartlett Tree Experts collaboration did not consider workforce development or training, these aspects have grown organically and are now a routine exercise supported by both groups.

In November 2024, the two organizations paired up for an inaugural Tree Climbing Academy, and more recently, March 15 and 16, 2025, they held an in-person training at Casey Tree Farm. The teaching combined online, digital training programs with in-person, analog training. Local Bartlett Tree Experts PHC specialists were trained in a variety of subject matters including technology resources, application procedures, truck and equipment maintenance, client relations and career development. These on-site trainings offer the opportunity for specialists to receive foundational education and to learn from others, which provides more effective service to Bartlett Tree Experts’ customers.

While visiting the premises, the specialists also received small-group training from Bartlett Tree Research Laboratories extension specialists on plant health care and were treated to a tour of Casey Tree Farm by Kyle Derr, director of Casey Tree Farm, and Dan Martin, farm field manager. The tour gave the specialists the opportunity to see the shared, ongoing research, especially as it applies to urban-tree survival, as well as train on the same tree species they care for on the job.

A lesson in symbiotics
In 2024, the Bartlett Tree Research Laboratories won a coveted Canopy Award in the field of “Partnership” from Casey Trees. Dr. Riley comments on that achievement. “Winning the Canopy Award really served as validation for what we’ve been working toward collaboratively. We’re excited for what the future holds, and it’s exciting to see the potential in working together far into the future.”

Conclusion
Partnership is an apt word to describe the relationship and collaboration between these two organizations collectively engaging in cooperative research, in-tandem trainings and sharing a common goal geared toward tree preservation and the survival of urban trees.

But it’s not only the D.C. metro area that is undergoing a decline in tree canopy, and it remains to be seen if the solutions in Washington can be applied to other communities. Buscaino continues, “In general, based on past United States Forestry Service (USFS) nationwide analyses, urban canopy across the U.S. is either stalled or declining.”

The ultimate success of the Casey Trees/Bartlett partnership may be that it encourages more organizations to work together for the benefit and future success of urban-tree survival.

Tim Bartelt is a freelance writer based in Buffalo Grove, Illinois, and has more than 20 years of work experience in the outdoor-
power-equipment industry.