Urban Jungle: Pavement bad, green good?
When you picture a calming, stress-free environment, what do you see? Most likely, you aren’t envisioning pavement. Spaces with trees, grass, and other vegetation types are thought to reduce stress in many ways, from enhancing attention and encouraging physical activity and social contact, to mitigating air pollution and heat. But does the type of vegetation make a difference? Does a grassy field have the same positive associations for childhood health outcomes as a treed area? Jarvis, who is part of a larger federally funded (CIHR) project called Born to be Wise, wanted to know.
A healthy start
“For my PhD, I’m investigating the association between early-life residential exposure to vegetation and childhood development in a population-based birth cohort in Metro Vancouver” said Jarvis. “We know that health and development in early life is a strong predictor for health across the life course, so understanding the benefits of natural environments on human health early on is really important.” Specifically, Jarvis explores the relationship between natural environments and human health environments across the lifespan, from early life to adulthood, and explores how greenspace can offer benefits.
So, what did Jarvis find? “We know from prior studies that, in general, higher residential exposure to vegetation in early life is positively associated with early childhood development, and that paved surfaces may be negatively associated with development. But we discovered through this research that the positive association may be stronger for trees than grass,” she said.
What could explain the increased benefit of trees over other vegetation types? Jarvis explains, “Trees may directly remove or act as a barrier to displace air and noise pollution, which can have adverse effects on children’s health. These include stress, disturbances to sleep, and damage to the central nervous system.”
Jarvis’s study analyzed data from nearly 30,000 children in Metro Vancouver born between 2000 and 2005. Their development was measured using the Early Development Instrument (EDI), a standardized tool used by kindergarten teachers in the second half of the school year to measure children’s ability to meet age-appropriate developmental expectations such as emotional maturity and communication skills. The environment surrounding the residential areas throughout the Lower Mainland was assessed using a high spatial resolution land cover map that was linked to children via postal codes. Then, the associations between land cover classes and early childhood development were analyzed.
This research built on earlier findings that children who were exposed to more vegetation within a 250-metre buffer zone around their postal code had a stronger likelihood of better developmental outcomes in kindergarten.
How this research impacts city planning
Urban greenspace takes many forms, from sidewalk gardens along a busy city road to towering tree-lined streets that cast shade in the summer months. Every day, city planners must make choices about what types of greenspaces are protected or implemented in different settings. But few studies have moved past the idea that vegetation is good and paved surfaces are bad to investigate the health associations related to distinct vegetation types. This is what makes Jarvis’ work so important. If cities plan to include greenspace without consideration of what type is most beneficial, they may not choose the best planning solution to help improve the health of current and future residents. Jarvis’ findings that the positive association may be stronger for trees than grass can inform urban planning efforts to support early childhood developmental health.
It seems like Metro Vancouver certainly takes the importance of tree cover to heart. Not only did they support this work and the larger “Born to be Wise” project through providing data, Metro Vancouver also proposed a regional target to increase tree canopy cover across the region by 8% in the next 30 years. An important goal given Metro Vancouver’s 2019 report showed increasing development and road expansions could result in declining canopy cover over the next three decades.
Laurie Bates-Frymel, a Senior Planner with Metro Vancouver Regional District, welcomes Jarvis’ findings. “I’m excited to learn from the Born to be Wise team that robust urban forests are helping children grow up healthier, happier, and smarter in our region” she said. “I expect various professionals – planners, urban foresters, environmental health specialists, and engineers – will reference these findings to bolster greenspace retention and enhancement efforts. Data-driven research is critical to inform community planning, policy development, and decision-making as our region grows and the climate continues to change.”
Think beyond the park: How can you implement this research into your daily life?
Given these findings, should parents of young children be concerned if they don’t live near a treed park? Jarvis says no. “Think about your daily exposure, nature doesn’t just exist in parks. There are so many beneficial settings to connect with nature like community gardens, sidewalk foliage, backyards, tree-lined streets, and more.” It can be as simple as making a few adjustments to a daily routine. “If you have yard space, incorporate some natural components, or choose a different route to school with your child that incorporates more of nature,” Jarvis explains. “And if you don’t have access to spaces where you can interact with nature, reach out to your city. There are some relatively easy to implement changes like incorporating small gardens along street boulevards for that tactile experience of nature.”
Growing support: A trans-disciplinary approach
How did a student in the Department of Forestry and Conservation Sciences find themselves at the intersection between public health and nature? Jarvis’ journey as a researcher has led her to realize the importance of an interdisciplinary approach and the guidance of a team of experts.
“It’s been important to have a group of committee members who have an interdisciplinary background to provide those foundational research skills,” said Jarvis. “Because I am not a student of public health, it’s been incredibly valuable to have Dr. Mieke Koehoorn as a mentor. From the methodology to how to communicate and share my findings, Dr. Koehoorn and the rest of my committee provided invaluable input from their own areas of expertise.”
Dr. Koehoorn, a CHÉOS scientist and a professor at UBC’s School of Population and Public Health, found value in her participation as well. “It’s a rewarding experience to be a committee member on a trans-disciplinary PhD supervisory committee” Dr. Koehoorn said. “Ingrid’s program of research was informed by committee members spanning population health, forestry, epidemiology, and applied public health positions with the Ministry of Health and the BCCDC and is exceptionally strong in research design elements. This instills confidence in the observed results and in opportunities for meaningful knowledge translation.”
A trans-disciplinary approach integrates the perspective of multiple disciplines, and in this case, Dr. Koehoorn explains, “The approach meant additional learning and effort to reconcile diverse perspectives and approaches, but also enabled complex and novel research questions, rigorous study designs, and significant contributions to our understanding of complex population health issues.”
Dr. Koehoorn felt it was important to take time for this project because she believes the trans-disciplinary approach is key to developing creative, evidence-informed prevention strategies for population and environmental health challenges and occupational health problems. So how does she feel about this project? “The result of this research is transformative. Ingrid’s findings add to our understanding of how green space impacts the health of populations across the life span and also informs specific recommendations for creating green spaces that maximize and protect health,” said Dr. Koehoorn.
Jarvis looks forward to continuing her work in Metro Vancouver as “there are endless possibilities and questions when looking at the relationship between urban environmental exposures and health.” And it sounds like there is still much work to be done. “Canada isn’t as well represented as other geographies around the world in research regarding the intersection of nature and health,” said Jarvis. “In the future, I would like to look more at how green spaces contribute to addressing health inequalities.”