How do trees and green spaces promote our health?

Trees enrich life in many ways. They fight climate change by reducing greenhouse gases in the atmosphere. They dampen noise pollution and reduce air pollution by sucking in carbon dioxide and releasing oxygen. When rain falls from the sky, trees reduce stormwater runoff, preventing flooding and soil erosion. They also provide valuable habitats to support the biodiversity of insects, birds and other animals as well as microorganisms. The list goes on.
It is equally important to gather evidence that simply being near trees and green spaces improves our health and mood. Below are some of the biggest benefits we get from it.

Stay cool: Trees help prevent heat-related illnesses

Climate change is leading to rising temperatures and more heat waves in the United States. These impacts are even worse for those who live in neighborhoods known as urban heat islands, where asphalt and concrete absorb heat during the day and continue to radiate it at night. Temperatures can be up to 2.5°C higher than in suburbs, rural areas or simply wealthier and greener areas.
Trees and their canopy provide shade and help prevent urban heat islands. What does this mean for the individual? This results in fewer heat-related health illnesses, which affect outdoor workers as well as younger, older and medically vulnerable people at higher rates. A study published inThe lancetcalculated that increasing tree canopy cover to 30% in 93 European cities could prevent an estimated four out of 10 premature heat-related deaths among adults in those cities.

How Trees Help Children: Better Mood, Behavior, Attention and More

Spending more time in nature has been linked to better health outcomes such as lower blood pressure, better sleep and improvement in many chronic diseases in adults. These findings are fueling growing interest in forest therapy, a guided outdoor healing practice that leads to improved overall well-being. The many benefits of trees and nature for children are also noteworthy.
A study of children ages 4 to 6 found that those who lived near green spaces exhibited less hyperactive behavior and performed better on tests of attention and visual memory than children who did not.
OnlySeeTrees can have mental health benefits. In Michigan, a study of children ages 7 to 9 showed that students who could see trees from their school windows had fewer behavior problems than students with limited vision.
In Finland, researchers modified daycare centers' outdoor playscapes to mimic forest undergrowth. These daycare centers were compared to control standard daycare centers and nature-oriented daycare centers where children visited the surrounding forests daily. At the end of the 28 days, the children in the daycare centers with modified playscapes in the forest undergrowth had a healthier microbiome and had improved markers of their immune system compared to their peers.

How green spaces help communities

Green spaces in the neighborhood also contribute significantly to the well-being of the communities. In a randomized trial in a US city, grass and trees were planted and maintained on previously vacant lots. The researchers then compared these green spaces with undeveloped land.
In neighborhoods below the poverty line, areas with leafy lots experienced a decrease in crime compared to pristine vacant lots. Meanwhile, residents who lived near leafy properties reported feeling safer and using outdoor spaces more for relaxation and socializing.

How can you help?

Unfortunately, urban tree canopy cover has declined over the years. To combat this decline, many cities and nonprofit organizations offer programs that provide trees for planting.
Some examples in Massachusetts include Canopy Crew in Cambridge and Speak for the Trees in Boston. (Speak for the Trees also provides helpful information on selecting and caring for trees.) Neighborhood Forest provides trees to schools and other youth organizations throughout the United States. Find a program near you!
Planting native trees in your area will better suit the local conditions, wildlife and ecosystem. For more information and advice, contact your regional Native Plant Society. If you are concerned about seasonal allergies from tree pollen, many tree organizations or certified arborists can give you advice on the best selection of native trees.
If planting trees isn't for you, but you're interested in contributing to the mission, consider donating to organizations that support reforestation, such as The Canopy Project and the Arbor Day Foundation.