URBAN STUDY CONFIRMS
TREES ARE COOL
Trees Are Cost-Effective and Pleasant Way to Cool Our Cities
(03/53) TRENTON - Trees can significantly
cool urban areas that generate heat and clean the air by
absorbing pollution, according to two studies sponsored
by the U.S. Environmental Protection Agency (EPA) and the
New Jersey Department of Environmental Protection (DEP).
The studies examined so-called "urban heat islands"
surrounding the cities of Newark and Camden and explored
various measures to mitigate their adverse effects.
On warm summer days, the air in urban areas
can be significantly hotter than in surrounding areas -
an effect called a "heat island." The problem
is caused by a variety of factors that trap heat, including
buildings and dark pavement that absorb the sun's rays rather
than reflect them.
"These two cities generate unneeded
heat, which is not only unpleasant, it can have real health
consequences for urban residents and for the environment,"
said Jane M. Kenny, EPA Regional Administrator. "The
good news is that there is a relatively simple and economical
solution - plant trees."
Kenny added that while it can take five
years or more for a newly planted tree to grow enough to
begin significantly cooling the environment and absorbing
pollution, the long-term benefits of trees are irrefutable.
"Johnny Appleseed had it right,"
said New Jersey DEP Commissioner Bradley M. Campbell. "These
studies reinforce the need for Governor James E. McGreevey's
initiatives to plant 100,000 new trees in New Jersey's urban
and suburban communities." Campbell noted that the
DEP already has begun planting more trees in Camden using
$1 million funded by a supplemental environmental project.
In the short term, Kenny pointed out, there
are additional steps that can be taken to reduce the "heat
island" effect. These include constructing buildings
using the principles of EPA's Energy Star program, which
can conserve energy and reduce demand and the pollution
that comes with generating electricity.
The two studies - conducted by Montclair
State University and National Aeronautics and Space Administration's
Goddard Institute for Space Studies with research assistance
from Columbia University - confirmed that both Newark and
Camden have heat islands. The average air temperature in
Newark can be as much as 11 degrees Fahrenheit higher than
its suburbs and Camden's temperature can top the surrounding
area by as much as 6 degrees Fahrenheit.
This increase in temperature is bad for
many urban residents' health. Hotter weather increases the
frequency of heat-related health problems, such as heat
exhaustion, and induces more asthma attacks, as the heat
concentrates air pollution and speeds up smog formation.
In addition, higher temperatures result in more expensive
utility bills as residents run their air conditioners longer.
The New Jersey studies point to tree planting
as a key strategy in combating urban heat islands in the
future. Trees serve numerous purposes. In addition to providing
shade from the sun, trees absorb carbon dioxide and filter
out pollutants from the air. They cool the air by excreting
droplets of water that draw heat as they evaporate, which
is a process called " evapotranspiration." Trees
also absorb sound, prevent erosion and provide habitats
for birds and animals.
"Trees also provide an attractive
canopy for urban areas, making communities more attractive
to business and tourism, transforming a neighborhood's appearance
and increasing home market value, as they bring nature closer
to where we live and work," added Campbell.
The studies also showed that heat islands
can be tempered by using lighter colored or more reflective
surfaces on buildings, roofs and streets.