Good trees are essential to healthy creeks. Their leaves and branches provide shade to prevent evaporation and their roots stabilize the banks so that the soil doesn't erode and clog up the main creeks that flow into larger bodies, like the San Francisco Bay.

A ranger from the East Bay Municipal Utility District says unfortunately neither the Pavon Creek, south of El Sobrante, nor the Pinole Creek into which it flows are in very good shape. Farmers destroyed them by cutting down trees and letting their cattle overgraze the land, according to EBMUD's Bob Flasher, who refers to himself as "Ranger Bob."

But Flasher and his partner Pat Matthews, known as "Ranger Pat," are changing that. With the help of students from El Cerrito's Tehiyah Day School, they are playing catch-up and slowly restoring the creeks.

"What we tell the kids is that Tu B'Shevat is the rangers' favorite holiday and that we celebrate it six months a year," said Flasher.

During half of every year he and his partner are involved in some phase of tree planting, either collecting seeds, germinating them, planting the trees, mulching or watering as part of their 2,800-acre creek restoration job with EBMUD.

"Ninety-percent of the wildlife in the West depends on creeks — creeks with rushes, cattails and trees," said Flasher. Creeks also are the habitat of steelhead trout and the California red-legged frog, which is listed as threatened by the U.S. Fish & Wildlife Service. The rangers started their creek restoration campaign, but with only two of them, they knew they couldn't accomplish too much.

That's when the student program was born. The rangers realized they could get some help planting and caring for the trees while teaching young people how to care for their environment and preserve it for future generations.

"East Bay MUD pays my salary and [that of his partner] so that we can do tikkun olam two days a week," said Flasher, referring to the time they spend in classrooms.

Flasher, who is Jewish, still feels guilty about cutting down trees in the 1970s when he worked for the East Bay Regional Park District.

"They hired me in 1973 to cut down eucalyptus trees to make a fuel break," he said, referring to a line of stripped vegetation that prevents a fire from spreading.

For seven years Flasher removed trees over a 30-mile-long perimeter. "I still feel bad about that. I think they should have just thinned them. That's why I'm planting hundreds of trees to replace what I cut down."

And he's taking lots of Bay Area children along for the ride. Both he and Matthews go into classrooms and teach the students about ecology and prepare them for their work at the creeks.

Over the past four years the program has been a tremendous success, drawing students from kindergarten to high school from schools throughout the East Bay. But last week at Tu B'Shevat was the only time that an entire school has ever come out to plant trees. Some 340 students, ages 5 to 14 from kindergarten through eighth grade, participated.

It was the result of one teacher's dream. Arella Barlev wanted to celebrate Tu B'Shevat with the students at Tehiyah Day School the way she celebrated it as a child on her kibbutz in Israel.

"I felt so strongly that planting at Tu B'Shevat is the essential way of celebrating the holiday," said Barlev.

But she didn't want to plant just one or two trees. She wanted to plant enough to make a difference, to have an impact.

Yet she wasn't having much luck making her Tu B'Shevat dream come true. Local and regional parks didn't respond to her phone calls. Then along came EBMUD and Flasher.

"I told Ranger Bob my dream, that the whole school will go out and plant at the holiday. He said, 'That's my dream, too.'"

And this year, in honor of Tu B'Shevat, the students and teachers from Tehiyah along with Flasher, spent three days planting 2,001 trees along the Pavon Creek. They planted oaks and buckeyes, which had been germinated either in their classrooms or by Flasher, and also willow trees.

"The willows are a cinch," said Barlev. "You just cut the branches and stick them in the mud. In six weeks they develop a root system and a couple weeks later branches. Within three months they are leafing and have everything a good tree needs."

According to Barlev, the project was an unqualified success and, if Flasher will have them back next year, she'll be there.

"The kids loved the project. Everyone goes home with a smile on their face. I think for some of the kids being covered with that much mud is heaven," said Barlev. "I'm so gratified. I'm experiencing total nachas."