Ambitious Louisville study seeks to understand impact of trees on our health


JUDY WOODRUFF: As we know, trees can add beauty
and a sense of serenity to a neighborhood. But, as John Yang discovered, researchers
have launched an ambitious project in Louisville, Kentucky, to see if greenery can also improve
public health. JOHN YANG: On a crisp morning in South Louisville,
a 20-foot evergreen is deployed into an urban laboratory. At the designated spot, a three-man crew painstakingly
lifts, twists and bends the tree, a green giant arborvitae, to be precise, maneuvering
it under a web of utility lines, until homeowner Mark Goeing is the happy treecipient. You turn around, you see that brand-new tree
in your yard, how does that make you feel? MARK GOEING, Homeowner: I think it looks beautiful. And maybe it is just a long-term impact that
maybe I won’t live to see, but trees are obviously a good thing for our environment. JOHN YANG: Goeing, a retired zookeeper, is
among the hundreds of South Louisville residents getting trees, shrubs and other greenery over
the next year. It’s part of a projected $15 million research
project conducted by the University of Louisville and sponsored by the National Institutes of
Health and The Nature Conservancy. It’s called Green Heart Louisville. Researchers say this project is the first
of its kind, a large-scale scientific study of how trees and green spaces affect residents’
health. It comes at a crucial time for the city of
Louisville. Between 2004 and 2012, the city lost an average
of 54,000 trees a year to development, storms, pests, and old age. During that time, the tree canopy coverage
in Louisville dropped to just 37 percent, well below other cities in the region. And since 1996, the American Lung Association
has given the city a failing grade for air pollutants like ozone. What’s more, Louisville is one of the nation’s
fastest-warming urban heat islands. Parts of the city can be 10 degrees hotter
than surrounding areas. Green Heart researchers think more trees could
be a solution. They can improve air quality, cool neighborhoods,
help combat global warming, and even muffle noise pollution. Chris Chandler is The Nature Conservancy’s
urban conservation director in Kentucky. When you look at a street like this, what
do you see? CHRIS CHANDLER, The Nature Conservancy: I
see an aged neighborhood with a declining urban tree canopy. It’s had a lack of stewardship over the years
and a lack of investments. Our old trees are dying, and they’re not being
replaced and managed over time. Nature is not a nice-to-have. It’s a must-have. JOHN YANG: So, streets like this are a focus
of the Green Heart study. Crews are planting and helping maintain around
8,000 trees, shrubs and flowering plants in South Louisville neighborhoods that are home
to about 35,000 people. Researchers have made baseline physical and
psychological health assessments of some 700 residents, checking their blood pressure,
lung capacity, and stress levels. Half the participants will get new foliage
on or around their properties. Half will not. After two years, they will be examined again
to compare changes between the two groups. ARUNI BHATNAGAR, University of Louisville
Medical School: This is a very ambitious project, both in terms of its scope, its time and its
resources. JOHN YANG: Aruni Bhatnagar of the University
of Louisville Medical School is the lead researcher. This is like testing a new drug. ARUNI BHATNAGAR: It is exactly like — same
methodology. We have a control group, in which there will
be no change in greenness. We have a treated group, where is we have
put greenness. So it’s exactly run like a clinical trial
with a placebo, but without — instead of a drug, we have trees. JOHN YANG: Research has already shown that
green space can relieve stress, but the team in Louisville wants to know more about its
effects on overall health. CHRIS CHANDLER: What we hope to unlock is
new foundational science that better allows us to understand the role that nature plays
in improving our health. And if we can do that, we can change blueprints
on how you build a healthy, just community to be green prints and to include nature in
that story. JOHN YANG: In Louisville, as in so many cities,
tree canopy coverage is a matter of rich and poor. The view from above tells the story. Wealthier areas, like this East Side neighborhood,
have up to twice as many trees as poorer areas in the South and West, which have histories
of discriminatory housing practices. And the difference in health outcomes is staggering. Due to a variety of factors, life expectancy
is up to about 13 years shorter on the West Side than the East. DR. SARAH MOYER, Louisville Public Health Director:
Your zip code determines your health probably the most. JOHN YANG: Dr. Sarah Moyer is Louisville’s
public health director. DR. SARAH MOYER: We have neighborhoods where people
are living really long and experiencing great quality of life. And so what is going on in those neighborhoods
that we can bring to other ones? Nature is one of those things that’s different
between those communities. And how do we bring that to everyone in our
city? AMY YATES, Louisville Resident: It’s pretty
much just always been bare in this area as far as trees go. JOHN YANG: Amy Yates’ South Louisville neighborhood
is dotted with reminders of where trees once stood. Yates says she inherited a green thumb from
her grandmother. AMY YATES: My grandmother and I planted this
tree in 2009, the year after my dad passed away, kind of as a memorable thing. JOHN YANG: The single mother of three has
lived in this house 15 years. She volunteered for the Green Heart study
partly, she says, because her 14-year-old son has asthma. AMY YATES: Trees produce oxygen. And they clean the air. You know, they’re beautiful. It sustains our life. It’s the lungs of our planet. JOHN YANG: She says she’s not entirely surprised
about her hometown’s health inequality. AMY YATES: I’m always very curious to see
how where we live affects us. You know, when you have kids, you want them
to live long, happy, healthy lives. And, sometimes, you’re limited with your means. And it is very sad to think that, because
of that, we might live less years on this planet because of it. JOHN YANG: And this experiment will determine
whether trees could spread a canopy of health over more neighborhoods. For the “PBS NewsHour,” I’m John Yang in Louisville,
Kentucky.