quality and have other environmental benefits. Though
there are some issues with pollen for certain folks, they
also capture harmful particulates and pollutants that
are swirling around in the air.”
But newer studies have shown the positive effects that
trees and green spaces have on our mental health.
“We didn’t know that was going on,” she said. “Research,
however, shows that just seeing green and trees low-ers our stress response. People are also less depressed
when they have consistent access to nature and trees in
the city. In summary, what we have learned is that there
are health benefits on many levels — some of it we are
aware of and a lot we’re not.”
Wolf said her team at the University of Washington has
also looked extensively at the economic impact of parks
and trees. One study from Portland, Ore., showed that
well-maintained trees had a positive impact on property values and that homes with attractive landscaping
“But just looking pretty doesn’t get you terribly far in
debates about spending public money on parks,” she
said. “When you can show that trees are good for our
health, you’ll get a little farther with your argument.
Though there are not as many studies about trees and
productivity, some of the literature suggests that when
workers can see trees, they have less sick days.
“In addition, having trees and quality landscaping in
our everyday living environments is what appears to
produce these results. This research indicates work productivity is higher, and that students in elementary
and high schools and on college campuses have better
attention to tasks and assignments on nicely landscaped
campuses. So there is a whole range of these positives
Wolf said she and her colleagues believe there are
tree- and greenspace-linked “cradle to grave” benefits
emerging from research.
“It started out as a bullet point here and a bullet point
there,” she said. “But we now have so much research
that we’ve summarized it on a website called Green Cities: Good Health ( greenhealth.washington.edu).
Well-maintained trees had a positive impact on property values
and homes with attractive landscaping sold quicker.
Klyde Warren Park in Dallas, Texas
Photo by Antrell Williams