It's no secret that Berkeley Lake has more trees than any city in Gwinnett County.

The 50-year-old former summer retreat has always treasured its natural architecture. It has the strictest tree ordinance in the county, says forester Dale Higdon, and one of the toughest in the state.

Vino Wong/AJC (ENLARGE)

Eric Kuehler of the U.S. Forest Service documents positions of trees with a PDA unit.

Vino Wong/AJC (ENLARGE)

Dale Higdon, senior forester of the Georgia Forestry Commission, measures a pine tree at Berkeley Lake.

• How Gwinnett cities will celebrate Arbor Day

What the city hasn't had, until now, is a sense of just what its lush canopy is worth.

Teams of professional foresters and arborists will fan out across the 700-acre city April 22-23 with state-of-the-art software to find out. In two days, they'll catalog the number, type and health of the trees along public streets and begin to document the state of the city's urban forest (a process that will take longer).

The effort is part of a pilot project by the U.S. Department of Agriculture Forest Service and the Georgia Forestry Commission.

It will provide Berkeley Lake with a comprehensive assessment of its tree canopy and advice on how to maintain and protect it.

Detailed reports like the one Eric Kuehler of Urban Forestry South will generate typically cost thousands of dollars. Berkeley Lake gets one, free of charge, for welcoming the arborists, who will learn to use a new software tool called i-Tree.

To Berkeley Lake City Council member Rebecca Spitler, the deal is a no-brainer.

"I'm pretty excited about it," Spitler said. "We have a nature lovers community . . . and I think it will be great for our city to know the value of our urban forest and how to properly maintain it."

The partnership came about through Higdon, a senior forester with the Georgia Forestry Commission. He knew Kuehler, met Spitler through the city's land conservancy, and realized their goals dovetailed.

Higdon has lived and worked in Gwinnett for 31 years. He's deeply concerned with the rate at which Gwinnett's trading open land for impervious surfaces — which he said is currently about 1-to-1. He said he's never come across anything like the tree canopy of Berkeley Lake.

"They have for a long time had what I consider to be one of the most comprehensive, most protective tree ordinances in Gwinnett, if not the metro area," said Higdon, who retires in May but says he will stay involved with the city. "Around the lake," he said, "are some of the oldest trees in Gwinnett."

The tools will allow governments to see how trees are more than window dressing.

"A lot of times, municipalities look at trees as these pretty things," Kuehler said. "That's nice and everything, but we don't want to spend thousands of dollars on pretty. What we want to do is show how these trees are helping."

They reduce energy costs and flooding, he said, intercept storm water and remove air pollutants — nothing to sneeze at in the capital of standstill traffic.

"What this software does," Kuehler said, "is put a price tag on these trees."

Like roads and sewers, he said, trees are infrastructure. Unlike them, trees appreciate over time: The larger the tree, the more benefits it provides.

Keeping the trees healthy, Kuehler said, costs money. But, he added, "They're going to give back a lot more than you put into them."

Berkeley Lake's neighbor to the south is on the same page.

Norcross received an Urban Forestry grant last year. Community Development Director Jennifer Peterson has asked the City Council for matching funds to pay for the $38,900 project. With approval, Norcross' tree assessment could begin in April.

Spitler has lived in Gwinnett for 22 years, and in Berkeley Lake for the past 5 1/2. Living in a subdivision built under the strictest of tree ordinances, her yard is filled with older trees.

She's grateful, she said, that early residents had the foresight to protect what's irreplaceable.

"Where else can you have a hawk come and sit on a branch in your backyard all day?" Spitler said. "How often do you have that — especially in a subdivision."

On Thursday, the team met at Berkeley Lake's tiny City Hall to hash out project details. While considering which roadways to document first, they made a serendipitous discovery.

The tree assessment kicks off on Earth Day.