Research Summary

Effects of trees, gardens, and nature trails on heat index and child health: Design and methods of the Green Schoolyards Project

School parks can serve as a tool for urban heat island adaptation and health promotion.

BMC Public Health

One way to increase children’s engagement with nature is to provide greater access to natural environments during school time. Some communities look to the use of nearby city parks to accomplish this goal. The Green Schoolyards Project worked with three schools in Central Texas to investigate how green features in joint-use parks impact heat index within the parks, and physical activity levels and socioemotional well-being of children using the parks. The population of the participating schools consists primarily of low-income Latinx children who are at high risk for nature-deficit disorder, heat-related illness, and physical inactivity.

Two separate studies were conducted. The first study examined the associations between heat index, children’s physical activity, and their interaction with green features (trees, gardens, and nature trails) in the parks. The second study assessed the impact of green features on student’s physical activity levels for different heat index conditions, along with their connection to nature, social-emotional learning skills, misconduct, and standardized test scores. This paper, however, addresses only methods and results of the first study and the physical activity component of the second study. The three school parks used for this study had different profiles of green features: the “intervention park” had added green features (including trees, wildflower meadow, and nature trail); the “low-green park” had relatively small amounts of green features (trees); and the “high-green park” had relatively large amounts of green features (i.e., trees, wildlife habitat garden, and nature trail). A variety of objective measures were used to assess tree canopy, heat index, and green features of each of the three school parks. An adapted version of System for Observing Play and Recreation in Communities (SOPARC) and accelerometers and Global Positioning devices were used to assess children’s physical activity levels and interactions with green features. Assessments were conducted in September and November 2019.

Results showed “extreme heat index conditions at school parks, significant differences in heat index across park sites, and more children interacting with trees during periods of high heat index than periods of moderate heat index.” The average daily heat index in September ranged 2 degrees Fahrenheit among park sites. The maximum daily heat index ranged from 103.4 °F under tree canopy to 114.1 °F on an unshaded playground. During 12 days in September and six days in November, a total of 1229 children were observed in target areas with trees, three children in target areas with gardens, and no children in target areas with nature trails. Girls visited target areas with trees slightly more often than boys.

This study adds to the literature by being one of only a few exploring the relations between green schoolyards, temperatures, and child health. The fact that children positioned themselves under trees during periods of high heat index suggests that “school parks can serve as a tool for urban heat island adaptation and health promotion in divested communities at risk of disconnect from nature (and its associated health consequences) and heat-related illness.” This study also adds to the literature by introducing methods that “can be used by public health researchers and practitioners to inform the redesign of greenspaces in the face of climate change and health inequities.”