Trees as a 'health-care ally': How medical facilities are using plants to heal patients and the planet

A health-care professional looks out a hospital window. (Getty Images / Kobus Louw)

When most people think about hospitals, they picture what goes on inside them. But what’s outside is important, too. A growing body of research suggests the greenery that surrounds medical facilities can have a significant impact on human health – and help diminish the greenhouse gases emitted by the health sector itself.

What’s needed are more trees, shrubs and grasses, according to the Canadian Coalition for Green Health Care, which launched a campaign to “rewild” medical facilities across the country last year. The coalition aims to restore land to its natural state by planting vegetation and introducing more green spaces.

Since as far back as the 1980s, studies have shown that even looking at nature from a hospital window may help patients recover faster. A U.S. study published in Science Magazine in 1984, for example, found that patients assigned to rooms with a window view of nature had shorter hospital stays after undergoing gallbladder removal surgery.

Studies also show green spaces can help boost a person's well-being while working as a carbon sink for surrounding communities, absorbing more carbon dioxide from the atmosphere than they release.

“Trees are often overlooked as a health-care ally,” says Dr. Myles Sergeant, the coalition’s executive director. “But they’re an incredible resource.”

So far, the coalition has helped plant “health-care forests” comprising a total of more than 45,000 trees, as well as grasses, shrubs and flowers.

Global emissions of greenhouse gases such as carbon dioxide have reached record levels in recent years. The latest report by the Intergovernmental Panel on Climate Change indicated global temperatures are 1.1 C above pre-industrial levels. The consequences are devastating, with experts highlighting the connection between climate change and the increasing intensity of extreme weather events such as heat waves, droughts and floods. Some scientists have also pointed to climate change as one of the factors behind the massive wildfires in Canada.

Sergeant says he became interested in the health benefits of trees about 15 years ago, when he was working as a family doctor at an inner-city shelter in Hamilton, Ont. He could see that his patients needed access to greenery, especially on hot days when asphalt would overheat and air quality declined.

“I knew I had a home to go to, where it was cool,” he says. “They had nowhere to go.”

Studies show that urban areas with minimal tree cover are associated with higher mortality rates, he says, and decreased exposure to nature may be a contributor to declines in mental health. A study published in The Lancet journal in 2023, for example, showed thousands of heat-related deaths reported in Europe during the summer of 2015 could have been prevented by increasing tree coverage in cities.

Access to green space can benefit patients with conditions such as depression, anxiety or attention deficit hyperactivity disorder (ADHD), says Sergeant, as well as hypertension, and heart and lung diseases. According to a 2015 study by Stanford University researchers, exposure to nature may also decrease the risk of mental illness by reducing rumination, a known risk factor, and by fostering positive emotions.

“I found myself thinking, gosh, I should be planting trees,” says Sergeant.

He began by trying to organize planting events in inner-city areas but found the effort challenging — the cost of tearing up sidewalks was prohibitive and city workers didn’t necessarily have the resources to care for the new vegetation.

Hospital grounds, meanwhile, have plenty of available space, Sergeant says, and he had a host of contacts he expected would be willing to plant and care for vegetation such as trees and shrubs. So in 2017, he began reaching out. Through partnerships with organizations such as Trees for Life and the Ontario Parks Association, the program has gradually expanded across Canada.

“We’re intentional about the trees we plant,” Sergeant says, noting that coalition plantings favour native, drought-tolerant and insect-resistant species that are the likeliest to thrive and adapt to a warming climate. “If we’re planting an evergreen, we might put it by a window to block a bad view. Or we’ll put a berry tree there, so the patient will see birds coming to feed.”

Working towards a net-zero health system

For Sergeant and many of the participating institutions and staff members, climate action is an important motivator. The health-care sector has a surprisingly high carbon footprint. A 2019 study conducted by Health Care Without Harm estimated that the health-care sector is responsible for more than four per cent of global greenhouse gas emissions – more than the aviation industry.

To reduce that outsized footprint, the Canadian Medical Association (CMA) has been calling for a national secretariat to work with all levels of government toward a net-zero health system. This could help scale efforts many hospitals are undertaking to reduce and reuse single-use plastics and medical supplies while prioritizing more environmentally friendly procedures and treatments.

Adopting a drug prescription strategy that decreases the use of unnecessary medications, for example, can reduce the greenhouse gases associated with manufacturing, dispensing and disposal. The United Kingdom’s Royal Pharmaceutical Society estimates that the production of medicines accounts for about 25 per cent of the National Health Service’s carbon footprint. Additionally, telemedicine and virtual appointments cut travel and related CO2 emissions.

“The health sector needs to be part of the solution, not part of the problem,” says CMA President Dr. Kathleen Ross, a family doctor in British Columbia. “There are easy-to-action, tangible steps we can take to have meaningful impact, right now.”

Rewilding hospital grounds can play an important part in carbon reduction, says Sergeant. Through photosynthesis, trees remove carbon from the air and store it, while also filtering out harmful particulate matter caused by burning fossil fuels.

Agnes Black, director of research at Providence Health Care in Vancouver, worked with her institution’s environmental stewardship team to organize upcoming tree plantings at four sites across the city.

“To me, planting a tree is one of the most hopeful things we can do,” she says. "It’s going to make air clean, and patients and staff happier and healthier.”

To finance the planting of 100 trees, Providence has launched a fundraising campaign asking members of the community to contribute $50 for a tree in honour of a health-care worker.

“It might be the surgeon who treated your brother’s cancer, or the midwife who delivered your child, or the respiratory therapist who helped manage your child’s asthma,” she says. “People are really responding.”

Rewilding health care has become popular in other countries, too. The United Kingdom has a National Health Service (NHS) Forest — an alliance of more than 360 health-care sites committed to greening their facilities. According to NHS estimates released in 2020, England alone could save an estimated £2.1 billion, the equivalent of C$3.66 billion, each year in treatment costs if everyone in the country had access to good quality green space.

Sergeant sees health-care facilities as anchor institutions that can inspire action across urban environments and spur positive changes within communities.

“Imagine if you come to a hospital and it’s a model institution, with trees and gardens that take your breath away,” he says. “Doesn’t that set an example for the rest of society?”

This piece is part of a partnership between the Canadian Medical Association (CMA) and CTV News. For more information on the CMA, visit www.cma.ca.