How City Trees Improve Educational Outcomes ?

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It is proven that the presence of trees in urban areas makes life more pleasant: natural cooling in the face of intense heat waves, air purification and psychological well-being. However, these large plants are of great help on a completely different subject: that of education.

As surprising as it may seem, it was a study conducted by researchers at the University of Utah that established this link, in the city of Chicago (Illinois). Published in December 2024 in the journal Global Environmental Change, it proved the positive impact of the presence of trees on the academic success of students, particularly those from disadvantaged backgrounds. Exploratory work; the influence of trees on education being an understudied area; led by Professor Alberto Garcia and ecologist Michelle Lee,

An ecological catastrophe as a social indicator

In the Chicago metropolitan area, ash trees were the most widespread non-invasive species, representing 18% of street trees, or approximately 85,000 specimens. These are trees that follow the layout of streets, selected for their shape, their resistance to urban conditions and their ability to adapt to the restricted space of sidewalks. In France, the avenue tree par excellence is the plane tree, although new species are increasingly present.

Unfortunately, the arrival of the emerald ash borer (Agrilus planipennis) a beetle native to Asia, has caused a real massacre on the tree population of Chicago. Indeed, the emerald ash borer lays its eggs under the bark of ash trees. The larvae then feed on the cambium (a thin layer of cells located between the wood and the bark of a tree, responsible for its growth in thickness), interrupting the circulation of sap and causing the death of the tree.

Between 2010 and 2020, half of these trees perished, while the survivors were in decline, according to data from the Morton Arboretum, a public garden and research center on Chicago's west side. The dramatic situation provided researchers with a life-size laboratory to study the impact of the disappearance of these trees on the education system.

School performance closely linked to the environment

By combining satellite imagery, data from Illinois standardized school tests and infestation records, the researchers developed a novel methodology. The study followed the academic performance of thousands of students in grades 3 to 8 (from CE2 to 4 in France) between 2003 and 2012, a period coinciding with the arrival of the destructive beetle.

The results are compelling: there is a direct correlation between tree loss and student academic performance. In neighborhoods where ash trees have died back, the pass rate on these assessments has dropped by 1.22%. This decline, seen only in areas affected by tree loss, represents hundreds of students who are no longer meeting state learning goals simply because of the deterioration of their school environment. A seemingly modest drop, but with considerable repercussions on the scale of the population of students in learning situations.

The canopy, a bulwark against inequalities

Because Chicago's poorer neighborhoods—such as Englewood, West Garfield Park, and Austin—had less tree cover to begin with, were less affected by the infestation. However, students from lower-income backgrounds attending schools in more affluent areas were particularly affected by the tree loss. “These students don't have the same resources to recover from the effects of extreme temperatures or pollution-induced headaches,” Garcia says.

The researcher is actually depicting a somewhat unusual context here. First, the disappearance of trees is not measured solely by the number of trees lost in a neighborhood. Second, the most vulnerable students are not necessarily those who live in the most environmentally degraded neighborhoods, but those who experience a break between their school environment and their living environment.

Those from modest backgrounds who attend schools in affluent neighborhoods are even more exposed to the consequences of the disappearance of trees, because they lose a reference environment to which they were accustomed. Moreover, these students generally spend more time in their school environment, increasing their exposure to degraded environmental conditions, unlike their more affluent peers who can move to air-conditioned spaces or more distant neighborhoods.

This situation, which may seem somewhat contradictory at first glance, proves to us that the distribution of trees in cities is as much a social issue as an environmental issue. Even though the study focused on the city of Chicago, it would be extremely interesting to conduct comparative studies to better understand the specificities of each urban context, in France for example. By comparing the results of studies conducted in different locations, it is much easier to strengthen the reliability of the conclusions drawn from the data collected and to identify general trends. Trends that could then guide us towards an improvement of local policies in terms of urban greening.

• A study has shown that the presence of trees in cities improves academic performance, particularly for students from modest backgrounds.
• The massive disappearance of ash trees in Chicago has revealed a direct link between a degraded environment and a decline in educational performance.
• Tree management in cities is as much a social as an ecological issue, directly impacting urban inequalities.

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