Street roots., September 02, 2016, Page 12, Image 12

Page 12
HEAT, from page 7
back into the area. There are a lot of
surfaces that we need in an urban area that
are absorbing the sun’s rays,” Wasiutynski
said.
There can be as much as a 15- to
20-degree difference in cool parts of the
city, such as Forest Park, or neighborhoods
that are shaded with a denser tree canopy,
such as Irvington or Eastmoreland, on a hot
day.
“Portland has some pretty significant
urban heat island effects,” said Bob
Sallinger, the Audubon Society of Portland’s
conservation director. Sallinger notes that
Portland ranks fourth in the country with
the most extreme urban island heat effects,
which is supported by research conducted
by Climate Central.
“Portland has a reputation as a green city,
but the green is not equitably distributed.
To some degree, it does correlate with the
amount of wealth and poverty that is in a
neighborhood.”
The map Shandas created detailed that
correlation for the first time by overlaying
the map of temperature readings with maps
showing the environmental assets — such as
tree canopy and bioswales — with
demographic statistics such as the poverty
rate, population density, the presence of
racial and ethnic minorities, and the number
of people who speak English as a second or
third language, the number of people under
age 18 and over age 65, and the number of
people whose highest education is a high
school diploma versus a college degree.
The connection between urban heat
islands and the traditional signs of poverty
and disadvantage is not an exact correlation,
but one that still surprised Shandas.
“Urban heat islands,” he said, “completely
overlap in many ways with those
communities that have the least resources.”
Pointing to the harmful health effects of
hotter weather, Sallinger said, “Those
neighborhoods are going to suffer the most
because you have higher poverty, (and they
are) the least equipped to respond well.”
Heat waves, in addition to causing heat
stroke and dehydration, can aggravate
health conditions such as asthma and other
Street Roots • Sept. 2-8, 2016
New s
the non-profit Depave, which removes
most effective tool that can be used to
pavement and asphalt to install gardens and
reduce urban heat island effect. But it can
other green infrastructure, said there are
take decades for a tree to mature - so there
is pressure to plant now.
ways to reduce urban heat island effect
“Our thinking is that the climate warms
without removing, for instance, an entire
and that we have more of these intense heat parking lo t
waves throughout the summer, we’re really
“A better way to impact urban heat
going to need these trees 20 years from now '
islands is to find places to insert trees so
in order to keep our communities livable,”
that you can expand the forest and shade
Wasiutynski said.
the pavement,” he said. “There are a lot of
Rockwood, a neighborhood that straddles
creative strategies ... to keep some of that
Portland and Gresham, is the poorest
hard infrastructure but use
census tract in all of
Oregon. According to the
it creatively and adaptively.
city of Gresham, the
It’s an urban environment.
URBAN HEAT ISLANDS
neighborhood has a
There are going to be a lot
See the Portland area map
canopy cover of
of compromises.”
created by Vivek Shandas at
approximately 15
Shandas is beginning to
percent, well below the
climatecope.org
study
how the height of
city average of 28
buildings
can cool local
percent.
temperatures. Taller
In July, the city -
ince the map of urban heat islands was
partnering with the East Multnomah County buildings provide shade, producing an effect
launched, city planners and
Soil and Water District, Friends of Trees,
he calls “urban canyon effect.” He concludes
environmentalists have been using the map Depave, the county, and Mt. Hood
that there are five main factors that can
to pinpoint places throughout Portland that
Community College - conducted an
determine whether an area is an urban heat
need the most work to reduce urban heat
inventory of the trees already growing in
island:
building height, the density of
island effect.
Rockwood, as well as places where trees
buildings in an area, the amount of
Kaitlin Lovell, the manager of the science
could be planted. The city will begin
pavement and blacktop versus tree canopy,
integration division of the Bureau of
planting trees in the neighborhood this fall.
Environmental Services, said the map and
and the height of the tree.
Other ways to reduce the temperatures
the way it overlays with demographic data
produced by urban heat islands include
“Each neighborhood will have a mix of all
have heavily influenced the city’s tree­
installing eco-roofs, depaving portions of
these things,” he said, and he advocates for
planting program.
parking lots and other asphalt surfaces, and
identifying solutions that are particular to
“It was finally understanding how it all
even painting roofs, streets and parking lots
each urban heat island. “Which strategy and
layered together,” Lovell said. “It was a
white so that the sun’s rays are deflected
mix of these strategies lowers that daytime
much more visual explanation of how we
and the amount of heat that is absorbed into
temperature?”
were already approaching our work.”
the surface decreases.
Research by David Sailor, a former
Portland and Multnomah County’s work
Lovell said the bureau builds bioswales or
Portland State University professor who
to reduce urban heat islands, however, will
plants street trees principally for the
worked with Shandas, has done research
benefits in managing the city’s stormwater
be only a small part of the effort to mitigate
showing that Portland’s tree canopy cover is
in particular blocks or pieces of a
climate change. Lovell said there is a
the most important factor that determines
neighborhood. Because of the map, Lovell
constant push and pull in any conversation
whether an area is cooler or hotter. A
said, the bureau can see that “the next block about climate change: reducing carbon
neighborhood with a high number of mature
over also has a need for street trees because
dioxide and other greenhouse gas emissions
trees and a thicker canopy cover can cool an
of urban heat islands” and extend the tree­
to
stop climate change and reducing climate
area by a several degrees, at least.
planting and stormwater work slightly
change’s
impacts on human health and the
During the 2015-16 fiscal year, BES’ Tree
further to also address urban heat islands.
environment.
Program planted 3,437 trees, 504 of which
“It’s one of those additional layers we
were planted in east Portland and 563 in
“We can’t stop (climate change) at a local
(now) consider,” she said. “It really helps us
north Portland.
level,” Lovell said. “These are efforts to
maximize opportunities to reduce urban
Trees and a robust urban canopy,
heat island.”
build in urban resiliency to weather climate
Sallinger and Lovell said, is probably the
Eric Rosewall, the executive director of
change.”
cardiovascular illnesses and even cause
people with already vulnerable health, such
as seniors, to have strokes or heart attacks.
Certain medications can reduce a person’s
ability to cope with heat.
Communities that are considered isolated,
such as people who live alone, seniors who
are often confined to their homes and
seldom travel, and homeless people who live
outside are at the highest risk for heat-
related illness, as well as people who don’t
own air conditioners or who live in places
where they can’t easily cool off.
“It all comes together in a perfect storm,”
Sallinger said. “If you’re (poor) and you’re in
an area that is covered with pavement and
cement, doesn’t have trees, doesn’t have
natural areas, doesn’t have a local swimming
pool... it just makes those communities
more vulnerable.”
S
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