Photo by Graham Cullen City arborist Tom Rippeon and several classes of Waverley Elementary School students smooth dirt around a young white oak tree being planted near the playground last week. Purchase this photo

He oversees management and maintenance of about 7,600 trees planted in city rights of way and on city property in Frederick .

That number will grow by about 500 as the maintenance of street trees in new developments comes under city management. But before that happens, he will inspect each tree looking for signs of disease and how it was planted. Trees planted too shallow can cause sidewalk heaving, said Rippeon, who has been city arborist since 2001.

Last month, the City of Frederick was named a Tree City USA by the Arbor Day Foundation for meeting four standards: having a tree board or department, a tree care ordinance, a forestry program and observing Arbor Day (the national celebration is the last Friday in April, but the state has designated it as the first Wednesday in April).

To recognize the city's 29th year as a Tree City, a total of 29 trees were planted along Monocacy Boulevard, Stadium Drive, at West Second and Record streets, and the 29th tree -- a white oak, the state tree -- at Waverley Elementary School.

Rippeon recently became a certified arborist/municipal specialist through a program of the International Society of Arboriculture.

"It was one of my goals," he said.

He also has some goals for the city's treescape. One of them is diversity.

"Ten years ago, 40 percent of the inventory was Bradford pears and red maples," Rippeon said. "We didn't know (Bradfords) had structural problems until 20 years later," when storm winds regularly ripped and splintered mature trees.

Ideally, there should be no more than 10 percent of any species. Three years ago, when the city removed mature Bradfords from East Church Street, Rippeon replaced them with 24 species of trees, including okame cherry, tree lilac, galaxy magnolia, winter hawthorn, red maple, amur maple and redbud.

Diversity reduces risk of widespread destruction, which has occurred with elms and chestnut trees and is occurring with gypsy moths and oaks, and the emerald ash borer beetle and ash trees, which are banned from being planted in an effort to control the beetle's spread, he said.

Rippeon said the average life of a street tree is about eight years, "though we have some that are 35 and 40 years old."

When the city is responsible for making the tree selection, Rippeon considers not only its location, such as under power lines, but what is planted nearby. An inventory program tracks what species are planted where and any maintenance issues or resident complaints.

The city also received a Tree City USA Growth Award for the sixth year for demonstrating progress in its community forestry program. Rippeon said the city planted more than 1,200 trees in parks last year.

And a third recognition, for the 13th year, came from the state in a PLANT (People Loving and Nurturing Trees) Award. This award was created to recognize communities -- schools and other organizations, small towns and cities -- for their tree planting and care efforts. Fort Detrick, Brunswick , Friends of Waterford Park and several county schools also received PLANT awards.

Urban trees provide benefits. Studies have shown they can increase downtown business by 15 percent, reduce storm water runoff, absorb carbon dioxide from the air and provide wildlife habitat. Those are some reasons "we want to keep the existing forest, not replace it," he said, when new development happens. With new plantings, "the benefits are 20 years down the road."

Citizens can request having a tree planted in front of their property, in the city right of way, by completing an application from the Parks Department. If approved, the property owner pays for the tree and after one year, the city is responsible for general maintenance.

If you already have a tree, you can help by keeping the tree weed-free and watering it during periods of drought, Rippeon said.