Rory Witter places a birdseed cake in a tree. A first-grade class at Daniels Run Elementary School in Fairfax made the cakes and another class placed them in a bird habitat on school grounds. (Jim Barnes/For The Washington Post)

Fairfax County Public Schools — already recognized nationally for its commitment to environmental education — has united with some of the largest school districts in the country to support environmental sustainability.

Joining the Green Schools Alliance District Collaborative with New York City, Chicago and other large school districts will help Fairfax obtain favorable prices for materials that advance conservation and environmental sustainability, school officials said. The group will also share ideas, attempt to influence policy and promote environmental education.

The collaborative will boost Fairfax’s commitment to sustainability, said Jeff Platenberg, assistant superintendent for facilities and transportation services. The schools recently switched to recyclable lunch trays, and plan to go polystyrene-free in cafeterias by the fall, he said, and they are seeking a lower cost option for meters that monitor utility usage.

Environmental Stewardship Program Manager Elaine Tholen estimated that the school system’s conservation efforts have saved $6.5 million since 2014, and said the school system has recycled 3,200 tons of material in 2015. Fairfax has 146 Energy Star-rated schools — more than any other school district in the country, she said.

“What we’re so excited about . . . is that it’s not just something our facilities side is working on,” Tholen said. “We’re also working on it very hard on the instructional side.”

Twelve Fairfax schools have achieved Green Flag status — the highest level of achievement — through the National Wildlife Federation’s Eco-Schools USA program, which evaluates school facilities and curricula, Tholen said. The federation also named Centreville Elementary School one of the top 10 green schools in the country, she said.

Last Friday, first-graders at one of those Green Flag Schools, Daniels Run Elementary in Fairfax, made birdseed cakes, which they placed in an outdoor habitat on the school grounds. Science technology resource teacher Lori Huberman Hayes explained that the food would help the birds, and perhaps other wildlife, survive the cold winter weather.

“We use the environment as a context for promoting the larger critical thinking, creativity and collaboration goals that we have for our students, to help them to see themselves as global citizens,” said Adam Erbrecht, principal at Daniels Run.

“While we’re also teaching the scientific facts and scientific processes involved, we’re using that as an environment to integrate language arts, math, writing and everything that we do,” he said.

Centreville Elementary has a “Green Team” of about 50 students who meet with an energy consultant, develop ideas to promote environmental sustainability and tell adults about issues that are important to them, Principal Dwayne Young said.

The children spend time outside, where they combine learning with physical activity, Young said. A trail on the school grounds runs through a forest with a vernal pool, where students can observe frogs and other wildlife, he said.

Students sometimes go outside for writing assignments, where they might describe the environment, he said. The school’s garden is shaped in geometric patterns, to reinforce math concepts, he said.

Centreville’s green initiatives also help children connect with the surrounding community, Young said. Members of the Green Team take unused food from the school cafeteria to a nearby homeless shelter, where they help shelve the food and serve it to people who are staying there.

“Those are really complex thoughts to teach kids — that delayed gratification, even if it’s not for your benefit, it’s for the greater good,” Young said. “But that’s exactly what we do in creating citizens. We do things for the greater good.

“When students have that experience, they grow up into responsible citizens,” he added.

Barnes is a freelance writer.