SAN PEDRO — When Claudia DuVal was an expectant mother, her expectations were high.  

“You know, you’re supposed to fall in love with your child the second they’re born,” DuVal said. “It’s, it’s (supposed to be) this amazing moment.”

But it was a letdown for DuVal when she had her first daughter, Emma, three years ago. She suffered from postpartum depression.

“Just extreme moments of sadness,” DuVal remembered. “And physical pain.”

Those are just some symptoms she experienced before and after she gave birth. DuVal also had to battle with intrusive and negative thoughts, wondering if she was being “a good enough parent.” She also had irrational fears for the safety of her newborn child and was even afraid to take him for walks lest something terrible happen to him.

She also felt extremely alone.

Luckily, before she had her second child, a boy named Walker, five months ago, DuVal got help through support groups, therapy and medication. She also attended support groups through an organization called Postpartum Support International.

Renewing life is nature’s most basic function. Yet, according to the National Institutes of Health, anywhere from 6% to 20% of mothers experience postpartum depression.

At the University of California, Irvine, another mother and a scientist and professor of public health, Dr. Jun Wu, had a quirky hunch. Maybe part of the problem, she reasoned, is “rooted” in nature — literally. Trees, or lack thereof. 

She launched a first-of-its-kind epidemiological study to examine the link between urban forestry — the trees planted in open spaces and on city streets — and the prevalence of postpartum depression. She recently published a scientific paper titled “The Association Between Urban Green Space and Postpartum Depression.”

“We are interested in green spaces because there are multiple benefits of green spaces,” Wu said.

Using hospital data, she pored over 40,000 reported cases of postpartum depression in Southern California in the Kaiser Permanente Health System. 

Then she looked at “street-views” from online maps of Southern California to count trees, one-by-one.

“This is a map of green space in Southern California,” Wu said as she pulled up something on her computer.

She pointed to a color-coded map of the Los Angeles area, depicting various kinds of green space. Wu even noted “grassy areas” to see if there were some benefits there. 

At the end of the study, Wu said she was able to find a correlation.

Simply put, the more trees that are in an expectant mother’s immediate environment, the less likely she is to suffer from postpartum depression.

Specifically, Wu said trees have “protective associations with PPD.”

According to the study, all things being equal, more urban and suburban tree-cover means fewer incidents of postpartum depression in that area.

A mother, for example, living on a street where she cannot see trees outside her window, or if she lives in an urban area with few trees, she does not have those “protective associations” offered by nature against possible depression.

Is it the smells? Is it the sound of the wind rustling through the leaves? Or is it the cooling shade that provides natural comfort to stave off a mother’s anxiety and depression?

Wu doesn’t know.

However, Wu hypothesized that there is also an exercise component when it comes to the health of pregnant mothers.

The shade offered by trees, she theorized, gives relief and encourages pregnant mothers to go out and to be more active. And more activity can decrease depression.  

The doctor, herself, wards off the blues with lots of bright lights around her desk. In the corner of her office, she has a large pillow and a mat where she can sit and mediate, and gaze out at the trees on the street below her office.  

Wu is a mother of two who did not suffer from postpartum depression. Even so, she said, being a mom isn’t easy.

“(It’s) very hard,” Wu said. “Harder than working. It’s just so important to have women… healthy and happy.”

Even though Wu could not establish a causation between trees and postpartum depression, her findings, if correct, identify a clear indicator. More trees mean better mental health for mothers.

Wu’s study also suggests that, in the interest of public health, cities have an obligation to promote urban forestry.

According to an MIT’s “Senseable City Lab,” which studies city design and development, Los Angeles has a very low “green view index” — the number of trees that can be seen at street level — compared to most cities in the world.  

As part of LA’s Green New Deal in 2019, then-Mayor Eric Garcetti proposed the city plant 90,000 trees to combat climate change. 

Duval said Wu’s research gets her full endorsement as a mother who endured unbearable postpartum depression. 

At a park near her home, DuVal sits beneath a tree and holds Walker so he stands on the grass.

“What is that you feel?” she asks him. 

DuVal said trees are naturally comforting.

“I can focus on the sounds of the leaves,” she said. “And so does he,” she added, referring to her five-month-old.

DuVal said she learned to experience the outdoors despite her fears and intrusive thoughts.

“To get a new mom out into nature, out in the open, that may be a little scary for them. Once you get out there, you’re going to feel better because that’s what nature does for us,” explained DuVal.