Is tree canopy disappearing?

By Jason Hardin
Greensboro, NC (June 24, 2007)- An acorn falls into the dirt. A shoot comes out. The seedling reaches for the sky. The tree grows into a towering oak. The oak is cut down to make way for a parking lot. Take that and multiply it by ten thousand, and it begins to tell the story of trees in the Triad. In a recent 16-year stretch, the tree canopy in and around Greensboro shrank by nearly a fifth as houses, roads, shopping centers, ice storms, disease, insects and other threats decimated the urban forest that graces the Piedmont.


The effects of the degreening of Greensboro are broad and long-lasting. With fewer trees, cities become hotter as they soak up the summer heat. Water flows more quickly into streams and rivers and picks up more pollutants on the way. Less carbon dioxide, a main contributor to global warming, is absorbed.
Then, there are things that can’t be measured with statistics. The pleasures of stepping into the shade of a massive oak on a sizzling day or seeing the flowers of a magnolia in bloom. Maureen Parker remembers a wooded area she used to pass on Pisgah Church Road near where she lives. A few years ago, it was clear-cut. “There used to be a forest there, and it was lovely.”
Attack of the red blobs
In 1984, hundreds of miles above the Earth, a satellite called Landsat cruised over Guilford County, taking pictures as it orbited. Sixteen years later, another satellite flew above the same ground. The difference is striking.
In a photo from 1984, the unforested areas show up in a glowing red color against a black background. Blobs are visible in the city’s core and in lakes. In 2000, twin red spheres have swollen around the city and the airport, and spider like tentacles shoot into the countryside. Analysts examined the photos and found that 18 percent of the tree canopy had vanished. That year, the city passed an ordinance that restricts the amount of trees that can be removed from some developments and requires that some replacement trees be planted.
The satellite-based study has not been updated, but experts agree losses are continuing. Theoretically, the ordinance should at least create a balance, with new trees replacing those cut down, said Randall Romie , a local landscape architect. “I don’t believe it’s doing that,” he said.
Hot enough for you?
The loss of trees doesn’t just alter the landscape – it changes the weather. As surfaces such as parking lots and buildings replace vegetation, a city stores more heat in the summer, enough to raise the temperature by several degrees, according to the Environmental Protection Agency.
That’s called the “heat island effect,” said George Hess, a forestry professor at N.C. State. “It plain gets hotter,” he said. That, in turn, can alter the weather, even creating thunderstorms, NASA scientists found. Sweatier summers aren’t the only change.
Trees remove pollutants from the air and help filter water . “If you scrape all the trees off a piece of land, it’s going to hurt the water quality,” Hess said. Heat also helps create ozone, which can trigger asthma and other respiratory problems. And that ozone can then damage trees, making them susceptible to other problems and worsening the heat island effect.
Disease, storms and hungry bugs also can take a toll on trees, but development is the main reason for the dwindling canopy. “Us humans, we are the biggest cause,” said Mike Cusimano, Greensboro’s urban forester. “Let’s not blame it on the insects.”
Changing the rules?
Greensboro and neighboring areas aren’t the only places trees are disappearing. It’s happening in Charlotte and Raleigh and similar cities across the country. But Greensboro and High Point have weaker protections than many other cities. Greensboro’s ordinance doesn’t preserve trees in new housing subdivisions or small apartment complexes, and High Point’s, with a few exceptions, doesn’t protect trees at all.
That’s in contrast to places such as Charlotte, where all forms of development must protect trees, or Charleston, S.C., where removing trees over a certain size is prohibited. Those involved in creating Greensboro’s ordinance say it was a first step. “It was better than what we had because we didn’t have anything,” Romie said. But it’s time to rework it, he said, He would like an ordinance that includes single-family houses and steps up requirements for large canopy trees such as oaks.
Another factor in preserving trees is the speed at which the city grows outward. More development in already established areas would eliminate some of the need to grow into forested land. A push for stricter tree rules could face resistance from the real estate industry.
Developers already plant trees in most housing developments, said Marlene Sanford , president of the Triad Real Estate and Building Industry Coalition. Preserving and planting trees does carry a cost , and some of that cost is passed to homeowners. In lower price ranges, that can make a significant difference, Sanford said. “At that point, every couple of hundred bucks makes a difference in whether people can qualify for homes or not,” she said.
On the other hand, removing trees also strips value from properties. Studies have found that having one big tree in the front yard increases a house’s sale price by 1 percent, and more trees can mean more value, according to the federal Center for Urban Forest Research.
While planting trees is great, a sapling can’t provide the benefits a massive, mature tree does, Cusimano said. “The truth is those trees are going to take 100 years to get as large as that 30-inch tree,” he said.
For the full article, visit the Greensboro News Record.