Are California elementary test scores more strongly associated with urban trees than poverty?

Tallis, H., Bratman, G.N., Samhour, i J.F., & Fargione, J. (2018). Are California elementary test scores more strongly associated with urban trees than poverty?. Frontiers in Psychology, 9. http://dx.doi.org/10.3389/fpsyg.2018.02074

Poverty and minority status are linked with lower academic test scores; urban trees and shrubs with higher scoresPositive links between greenspace around schools and academic benefits to students are documented in the literature. The size of these benefits relative to other factors and a clear understanding of which  features of greenspace are most beneficial are not well understood. This study investigated the strength of different greenspace effects in relation to other common variables related to student performance.

Researchers accessed fifth-grade data from the California Standardized Testing and Reporting (STAR) system for the year 2012.  The data used for this study included student test scores, student socio-economic information, and school demographics of 495 elementary schools in the California Public School system. The schools were chosen through stratified random sampling from a total of 3,233 possible schools with attention to student body SES, urban versus rural setting, and ecoregion. Researchers also collected data on three greenspace variables around each school: the normalized difference vegetation index (NDVI), which quantified greenery in school surroundings; an agricultural/nonagricultural dimension; and proportion of area around school occupied by trees or shrubs. These variables were considered within buffers up to 1 km from schools. Each school was also assigned one of eleven ecoregion identifiers based on latitude.

Urban schools tended to have higher test scores than rural schools. Schools serving a greater number of low-income students and under-represented minorities had the lowest scores.  Minority representation had roughly three times greater effect on test scores than urban/rural context and socio-economic status. Of the minority students, 75% were Hispanic. In the urban areas, schools with average tree-cover had higher standardized test scores than schools with low tree cover. Schools with more tree and shrub cover within 750 and 1000 meters of urban schools had the highest test scores. No association was found between test scores and NDVI or agricultural area

The overall findings indicate that urban tree and shrub cover in the neighborhoods around schools is positively associated with academic performance. “These results support the design of experimental tests of tree planting interventions for educational benefits.” Tree and shrub plantings could also provide benefits to the environment by increasing wildlife habitat and to human health by reducing air pollution and the heat island effect of cities. Further research across disciplines is warranted.

The Bottom Line

Poverty and minority status are linked with lower academic test scores; urban trees and shrubs with higher scores