Mollie Hudson was in the eighth grade when she and her two best friends at Tehiyah Day School in El Cerrito set a lofty goal for high school.

This goal had nothing to do with the typical teenage trappings that fill a 14-year-old’s brain.

The girls’ dream was to go to Kenya. But there would be no safaris for Mollie, or her two friends, Shanni and Leore Geller — this trip was all about community service.

“We always wanted to go to Kenya,” Hudson said. “I knew it was a place that needed a lot of attention. And I had to see it.”

Last summer, the 17-year-olds accomplished their goal. And when Hudson returned from the three-week trip to Kenya and Tanzania, she set another one.

She would organize and execute a 5K walk/run to raise money for the Kenya-based Green Belt Movement, an organization she volunteered with while in Kenya.

“Tehiyah had a big influence on me. The school really promotes community outreach and social justice,” she said. “When I first started looking at trips to go to Africa — and there aren’t that many — it wasn’t even a question that I would be doing a volunteer trip. I wanted to become more culturally aware and a part of this world.”

The 5K Run for the Trees happens May 3 in San Francisco’s Golden Gate Park. Hudson has planned the race almost entirely on her own.

When Hudson first called the Green Belt Movement’s U.S. headquarters to get advice about planning a fundraiser, the office manager, Shelly Fine, was surprised.

“At first I didn’t realize she was only in high school,” Fine said. “I typically get calls like that from college students. I’m really amazed by what Mollie is doing.”

Hudson credits the director of the San Francisco Nike Women’s Half Marathon for her help (Hudson called her to get some advice about how to plan a run/walk fundraiser), and her parents David Hudson and Jan Schreiber, who she said have been hugely supportive.

Hudson attends the Urban School of San Francisco and in the fall will be a freshman at Macalester College, a small liberal arts school in Minneapolis. She has dark curly hair, fair skin and a sweet disposition, the kind that invites conversation from strangers.

The trip Hudson and her friends chose was organized by Drew School, an independent school in San Francisco. Hudson saved money for three years to go to Kenya; her parents matched her effort.

The trip emphasized cultural immersion and community service. The 11 students spent one week in a home stay in the mountainous Nyeri region in Kenya. When they arrived, the villagers greeted their bus with dancing and singing.

There, they planted trees in collaboration with the Green Belt Movement, a grassroots initiative that empowers women to plant trees, thereby addressing Kenya’s major environmental challenges such as deforestation and soil erosion. The organization’s founder, Wangari Maathai, was the first African woman and the first environmentalist to receive the Nobel Peace Prize in 2004.

The students also spent time with children in the village, learning about their daily lives and sharing about their own in America.

Then the students spent two weeks in Tanzania, where they learned how to batik, play African drums and speak basic Swahili. They also spent time hiking in Arusha National Park and with the Maasai, an indigenous, nomadic tribe in East Africa.

The Maasai men and women welcomed the American students by sacrificing a goat and serving it to the group with milk and cow’s blood (a traditional fare that Hudson politely declined to drink). The Maasai warriors were eager to be photographed; the women gave the students jewelry they had made.

Hudson was overwhelmed by the cultural differences.

“A lot of the trip was learning how to be comfortable with being uncomfortable,” Hudson said.

She plans to go back to Kenya in 2010 to volunteer again with the Green Belt Movement. In the meantime, she hopes her Run for the Trees 5K raises at least $5,000, which would be enough money to plant 2,500 trees in Africa.

The 5K Run for the Trees will start at 9 a.m. May 3 in Golden Gate Park. The race begins at the band shell on Hagiwara Tea Garden Drive. $35 registration; proceeds to benefit the Green Belt Movement. To pre-register, go to www.active.com. For more information, contact Mollie Hudson at (510) 847-2834.