The gem of Frederick Law Olmstead's Emerald Necklace, Franklin Park, is getting a shine this summer. A 32 youth with Franklin Park Coalition and six from Youth Build Boston are working to spruce up areas inside the 527-acre refuge that connects the distinct neighborhoods of Dorchester, Mattapan, Roxbury, and Jamaica Plain.

The Franklin Park Coalition's Summer Youth Conservation crew is made up of teenagers, ages 15 through 18, working in paid positions to improve the grounds, specifically 220-acres of woodlands that are in need of care.

Invasive plants, such as the Japanese knotweed and the glossy buckthorn, prevent the forest from reaching optimum health. Christine Poff, the coalition's director, said that in order for a forest to be healthy, there must be diversity in the age and heights of the trees. The 12 to 15 foot knotweed and buckthorn, Poff said, limit that diversity by making it nearly impossible for anything else to grow and creates a false sense of danger in the passerby.

"It prevents an acorn, falling off an oak tree, from taking root and you don't get a baby oak tree," Poff said, adding that the invasive plants' heights "really hinders the sense of public safety."

A number of the coalition's crew works on ridding the woods of invasives by cutting the plants down and pulling them up by the roots. The crew, which began working two weeks ago, has cleared a field of invasive plants which they will then cover with woodchips to prevent the plants from growing back again.

Jose Figueroa, a crew worker back for a second year, said that he thinks what they are doing is making a difference. As he pulls out a cluster of Japanese Knotweed, he says the park will feel safer, "if it's cleaner and neater and not as scary as it looks now."

While pulling up the invasive plants, the crew found odd things like a wallet with identification cards that date to the early 1980s, a coconut shell, old lotion bottles, and a pillow. The crew is thinking about transforming the portion of the field that hasn't yet been cleared of invasives into a maze of the tall weed children can play in.

"Its fun and it's something different. Not everyday do you pick up a rake," said Makayla Sparks Sparks.

About a five-minute walk from Franklin Park's "Valley Gates" entrance, next to Playstead ballpark, a three-teen crew maintain a trail beaten down with heavy use over the years by local high schools, colleges, and cross-country race competitors.

"We're carving out the trail, making it smooth so people can walk on it," said Chris Terrel, 17. Over the coming weeks, the conservation crew will be recreating two to three-foot wide trails with an incline for proper drainage. They will continue laying down a sturdy surface of woodchips to slow wear and tear and re-vegetate the land on both sides of the trails.

Crew leader Kate Swartz is with a national non-profit organization that is partnering with Franklin Park Coalition this summer. The Student Conservation Association brings in six people that help the youth learn about the grounds and lead site work.

"What we're hoping for is park preservation, conservation, as well as helping youth get an appreciation of nature through environmental education," Swartz said.

In addition to restoration work, the FPC's Summer Youth Conservation crew tries to get more people to use the park with Drop-In Youth Sports Nights every Wednesday through Thursday. Instead of doing invasive or trail work a group of the teens go into neighborhoods that surround the park and distribute leaflets encouraging people to come out for a night of sports, hamburgers, and hot dogs.

"I like seeing the kids around, everyone in the community. There's no violence," said Figueroa. Sparks said she was surprised to find that a lot of people come out.

"I think it just reminds people to be opened-minded," she said. "There's more things to do than stay at home, watch TV, and eat."

The Summer Youth Conservation Crew isn't the only teenage crew working on improving the Franklin Park grounds. Project Advantage, a program through the non-profit organization Youth Build Boston, is a six to nine month GED and job skills program. Youth ages 16 through 19 learn about and train for a future career in the green industry.

One of the sites that Project Advantage works on is Franklin Park's Ruins Overlook, a site that once housed an overlook shelter and is located above White Stadium. The Project Advantage group comes to Franklin Park on Thursdays to learn about and work on vegetation control, drainage problems, and invasive plants. One project that they worked on was a 300-foot-long bench on the Ruins Overlook, which was completely covered by weeds.

"The goal is just to bring back a piece of the park that's been neglected," said Peter Hinrichs, project manager for Project Advantage, adding that it's also a resource to the students' training. "It's great for our students, its great for the public to see."

Both organizations want to make the Franklin Park a place that more people can enjoy. In addition to introducing youth to a "green path", Poff said, "our goal is to get more people in the park, to get young people in the park and become park stewards."