Standing beneath a gnarled Chinese tallow tree on a cold day, the small bunch of 4- and 5-year-olds were reminded that trees live, breathe and drink water.

That tree’s broken branches had regrown, kind of like whiskers on a man’s face.

“Plants are kind of just like us,” the children’s teacher, Zefferino vonKurnatowski told them later. “We’re going to show you how.”

Once a month, these children meet for Biggz Kidz, a program that connects Baton Rouge children with the natural world. A community project from Biggz Professional Tree Care, the class meets once a month at different YMCA branches to teach different aspects of urban forestry to pre-school and kindergarten-age kids.

For the January lesson, the children started out looking at the bare tallow tree behind the A.C. Lewis Branch of the Capital Area YMCA on North Foster Drive. The tree’s leaves had blown off months ago. It was still alive, they were assured, just like all the plants around them.

Inside a classroom at the Y, they watched a science experiment that illustrated a bit of their December class on the water cycle — carnations and daisies placed in colored water changing color.

They were starting to learn that plants drink water the same way they do.

“And the rain gives the trees a drink?” asked 4-year-old Louis Baustian, one of the least shy of the class. “I wish I was a tree and when it rained, I got a drink.”

The Biggz Kidz urban forestry program puts children in the woods and teaches them how trees affect their lives, said vonKurnatowski, the 37-year-old owner of Biggz.

“We want to help instill an environmental identity in children, especially to get them in touch with this new research, so as they grow up they don’t just see trees as something in nature,” vonKurnatowski said. “They’ll see trees as part of their nature in the city, and these trees will help them feel better, will help them physically.”

Most people know that trees perform important functions, like removing carbon dioxide from the air to purify it. Urban forests have other benefits, vonKurnatowski said.

One 1989 study found that workers who could view natural scenes and urban forests from their desks used less sick time, according to the Center for Urban Horticulture at the University of Washington. Housing projects with more grass and trees have fewer instances of domestic conflict, according to a 1996 study from researchers at the University of Illinois-Champaign.

“People aren’t aware of the human health benefits that trees provide,” vonKurnatowski said. “They just don’t think about it. Intuitively, it makes sense, but there is robust, sound research those trees will do this.”

Once an active kid at the local YMCA, vonKurnatowski wanted to work with the organization. He decided to create Biggz Kidz and give children a chance to earn points through the program that can eventually be turned in for Y memberships or a savings bond.

“To me, it is superb marketing,” he said. “It’s something I want to do and people will see it. Instead of sending out fliers, which I can’t stand, let’s do something fun that people will see.”

Lindsey Litchfield brought her 5-year-old daughter, Adele, to Biggz Kidz because Adele enjoyed working in the garden more than playing soccer.

“I agree that kids need to know more about the environment,” said Litchfield, 30. “We see all these buildings going up and parking lots being built. They need to know the importance of keeping the trees.”

In the second half of the class, vonKurnatowski and instructor Amelia Wolfe read a story called “Are Trees Alive?” to the children, showing all the ways trees live and help people. They saw pictures of trees giving fruit, shade and flowers to people.

“In some of these pictures we saw today, the trees lived over 100 years and were still alive,” said Wolfe, 24, who works full time at the Louisiana Department of Natural Resources.

After some thought, 4-year-old Cormac Whittington announced, “I want to have a tree birthday party!”

While Wolfe and the children made shapes like trees, vonKurnatowski left to dress up as the class mascot, Tyrone the Tree.

Designed as a soft, brown suit with two tree branches sticking from the head like antennae, the Tyrone costume is goofy and cheerful.

When Tyrone arrived, he was missing a limb from all the wind outside, he said.

“Can you grow another one?” Wolfe asked.

“Probably, I’m pretty healthy,” the tree replied.

The Biggz Kidz classes complement the children’s traditional education, said Joe Baustian, 34, the father of Louis.

“He spends eight hours a day in school,” he said, “so it’s nice for him to get some education outside, too.”