NAIROBI, Kenya — Wangari Maathai, the first African woman recipient of the Nobel Peace Prize, died after a long struggle with cancer, the environmental organization she founded said Monday. She was 71.

One of Kenya’s most recognizable women, Maathai won the Nobel in 2004 for combining environmentalism and social activism. She was the founder of the Green Belt Movement, where over 30 years she mobilized poor women to plant 30 million trees.

Edward Wageni, that group’s deputy executive director, said Maathai died in a Nairobi hospital late Sunday. Maathai had been in and out of the hospital since the beginning of the year, he said.