Paradise Paved:
Chatham adding almost 3 acres of built surfaces per day
By Mary Landers
The Savannah Morning News
March 11, 2007
Chatham gains almost 3 acres of built surfaces a day as green space
shrinks steadily.
Southern Belle that it is, Savannah might not like the time-lapse
images researcher Liz Kramer makes.
In them, the view of the metropolitan area since 1991 grows paler as the
tree canopy fades away. Blotches of paved and built-over surfaces
increase during the same period.
Using satellite data, Kramer , who directs the Natural Resources
Spatial Analysis Laboratory at the University of Georgia's Institute
of Ecology, has created similar time-series maps for counties all
over Georgia [8]. They tell her that the Savannah area is tied for
sixth place among Georgia counties with the most rapidly changing
land cover.
In fact, Chatham County has gained almost three acres per day of
paved or built-over surface while losing 28 acres of tree canopy per day
from 2001 to 2005. That translates into a cumulative loss of 41,327
acres of tree canopy and a gain of 3,802 acres of impervious surface.
The numbers alarm Paul Wolff, a Tybee Island City Council
member who is greener than Savannah on St. Patrick's Day.
"That's terrifying," he said. "When you hear numbers like that, it's in
Brazil or far from home. And we're replacing it with concrete and
rooftops."
Concrete consequences
The bird's-eye view of the landscape helps many to acknowledge what they
already know at some level, Kramer said.
"It's happening all around. I don't think people understand the
cumulative effects of land-use decisions," she said. "We haven't
recognized what that tree loss looks like."
The effects are far-reaching, said David Kyler, executive director
of the Center for a Sustainable Coast.
More impervious surfaces - such as roads, buildings and parking lots -
mean less rain soaking into the ground. That leads to more runoff
carrying more pollutants to streams. It also contributes to more
flooding.
And then there are energy issues.
"You also have increased heat buildup, a heat island," Kyler said.
"That means more energy use."
A greater demand for electricity further strains waterways because power
plants use water for cooling, losing some to evaporation and thermally
polluting waterways.
Kyler is especially concerned that the rate at which coastal
Georgia is getting paved over is outstripping its already robust
rate of population growth.
"We are suffering a high rate of population growth, yet we have double
that rate of increase in pavement," he said. "We all have bigger homes,
bigger lots, bigger driveways. It's the gated community, big starter
castle mentality. People have more dollars than sense."
The value of trees and unpaved surfaces is one of avoided costs, said
Jeffrey Dorfman, professor of economics and co-director of the Land
Use Studies Initiative at the University of Georgia.
"More trees and unpaved surfaces soak up more water naturally, leaving
less money spent on stormwater systems," he said. "They save you from
having to spend money. You can't spot it, but if it weren't there you'd
spot your taxes going up."
Canopy comeback
Researchers who analyze growth patterns have a saying: "The last crop is
blacktop." That means built areas rarely revert to their natural state.
But canopy loss isn't so set in stone - a point Krameris the first
to reiterate.
In fact, tree cover went up in Chatham County from 27 percent in
1991 to 33 percent in 2001. It was the subsequent building boom, much of
it on former pine plantations in west Chatham, that slashed the canopy
after that.
"There were a lot of clear cuts on the border of the county as land
moved out of forestry, like at that Pooler site," Kramer said.
"Some of that canopy is going to grow back."
Regrowth is part of why Kramer's canopy numbers don't worry Gordon
Denney, Savannah’s landscape architect. The city's tree ordinance
is designed to give Savannah a 50 percent canopy cover, a baseline
derived from studies conducted in the 1980s, Denney said.
Savannah already is at a point at which it is replacing more trees
than it removes. It just takes a while for those trees to grow their
mature canopy.
Denney points to a historical example."Look back at old photos of
Victory Drive, and all you see are large palms, no street canopy," he
said. "A hundred years later, it's a canopy-lined street that's just
amazing."
It can take decades for a large hardwood to provide maximum shade, but
it will happen, he said.
At least it will in Savannah and unincorporated Chatham County, where the tree ordinances are strong.
Tree advocates such as Dale Thorpe of the Savannah Tree Foundation
[36] have more concerns about Chatham's other municipalities, some of
which have only token ordinances and lack enforcement. The Savannah Tree
Foundation operates county-wide and is putting a greater emphasis
on those municipalities.
"We are trying to move westward and did just have a planting in Port
Wentworth," she said.
The Georgia Forestry Commission is targeting those same
communities.
Forester Daniel Westcot has set his sights on Pooler.
"Pooler has a tree ordinance, but it's noneffective," he said. "It
doesn't require much as far as planting trees back or protecting trees."
Those items are essential to keeping the Savannah metropolitan area
well covered in green, Thorpe said.
Still, Kramer's numbers - the 28 acres a day of canopy loss - give
Thorpe pause, even as she enjoys Savannah's tree-lined streets
daily.
"I think we're under attack and need to get smart," she said. "I'm a
little floored, like: 'Oh dear, we really need to renew our efforts.'
Maybe we've been fat and happy."
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