In 1922, Joy Morton turned 175 acres of his Illinois country estate into a tree museum west of Chicago; a century later, the Morton Arboretum spans 1,700 acres

Long before people talked about eco-anxiety or screen fatigue, one Chicago-area businessman found a simple answer: plant a museum’s worth of trees and let people walk through it. A 2025 study titled ‘Mapping arboretum research: Trends, gaps, and opportunities for biodiversity conservation, society, and climate resilience’ in Plants, People, Planet traced more than a century of published research on arboretums throughout the world and found that these tree-focused living collections have become important sites for conserving biodiversity, increasing climate resilience, and reconnection with nature.

That makes an appropriate context to revisit one of the most surprising time capsules of the Midwest: on December 14, 1922, businessman Joy Morton set aside 175 acres of land from his own private country estate at Lisle, Illinois, located west of Chicago, and made it open to the public as a place solely dedicated to trees. As Arboretum president Gerard T. Donnelly has said, trees add real value to people's well-being and make neighborhoods better places to live, and that has long been central to the Arboretum's mission.

A tree-planting family


Tree planting was part of the Morton legacy even before 1922. Joy Morton's father, J. Sterling Morton, founded Arbor Day in Nebraska in 1872, a day wholly dedicated to tree planting. Joy was raised in that spirit and later carried it forward. Appropriately enough, the Centennial Tree Planting Program was initiated by the Arboretum in April 2022, which was coincidentally also the 150th anniversary of Arbor Day, with a vision to plant 1,000 trees throughout the seven-county area of Chicago. By the time Joy Morton died in 1934, just twelve years after founding the Arboretum, the grounds had grown to 735 acres, with a general landscape plan, extensive plantings and nurseries, and a small but dedicated staff already in place. The Arboretum's now well-known education program began in 1940, when board chair Jean Morton Cudahy invited naturalist May Theilgaard Watts to teach; two years later, Watts's program became the first of its kind among U.S. arboretums.

From one estate to 1,700 acres

The Arboretum has grown steadily over time. What started as 175 acres of prairie and woodlands on the estate of Morton is now spread out over 1,700 acres of collections of trees, gardens, and natural landscape. The Arboretum welcomes more than a million visitors annually, making it one of the most popular cultural attractions in Illinois, alongside long-running draws such as the Illumination winter light show and rotating exhibitions like Human+Nature.

Not just a pretty walk, a science hub too

What sets the Arboretum apart from a nice weekend destination is the research taking place behind the scenes. One such study conducted in 2020 by Sean Hoban, a conservation biologist at the Morton Arboretum, published in Proceedings of the Royal Society B, compared how many individuals from a species are needed to adequately capture its genetic diversity in living collections, examining five plant genera. The study found that the necessary sample size varied widely even between closely related species, showing that taxonomic similarity alone can't predict how large a collection needs to be to safeguard a species' genetic diversity, underscoring the conservation value of living tree collections as well as their aesthetic appeal. The Arboretum also established the Chicago Region Trees Initiative in 2014, with partner Openlands, to improve tree canopy and environmental equity in under-resourced neighborhoods across the region.

Why this matters to a generation that grew up online

Here is where it comes full circle for us. An extensive study titled 'Urban Trees and Human Health: A Scoping Review' published in the International Journal of Environmental Research and Public Health reviewed more than 200 articles and found a correlation between time spent among urban trees and lower stress, better moods, and reduced exposure to heat in cities. To an entire generation suffering from climate anxiety, screen fatigue, and a lack of outdoor experiences, a one-hundred-year-old tree museum is not merely an artifact of nostalgia. It's a living example of what those researchers are describing.

A century on, still growing

For its 100th anniversary, the Arboretum marked the occasion with The Grand Garden, a two-acre open space that cost $16.5 million and debuted in September 2022, along with new large-scale sculptures by artist Daniel Popper and about 100 other programs throughout the year. According to Gerard T. Donnelly, the president of the Arboretum, the work of the organization is especially important now because of challenges like climate change and pests, and the hope is to maintain resilient trees for many years to come.