Story highlights Obama says "her legacy will stand" on environmental and other issues

U.N. Secretary-General Ban Ki-moon describes her as a "pioneer"

The Green Belt Movement founder was elected to Kenya's parliament with 98% of the vote

She was the first woman from Africa to win the Nobel Peace Prize

Kenyan Wangari Maathai, the first woman from Africa to win the Nobel Peace Prize, died Monday after a battle with cancer. She was 71.

Maathai, an environmentalist, had long campaigned for human rights and the empowerment of Africa's most impoverished people.

More than 30 years ago she founded the Green Belt Movement, a tree-planting campaign to simultaneously mitigate deforestation and to give locals, especially women and girls, access to resources like firewood for cooking and clean water. They have since planted more than 40 million trees.

"Professor Maathai's departure is untimely and a very great loss to all who knew her -- as a mother, relative, co-worker, colleague, role model and heroine -- or who admired her determination to make the world a more peaceful, healthier and better place," her organization said.

In 2004, she was awarded the Nobel Peace Prize for her efforts to promote sustainable development, democracy and peace.

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"Her departure is untimely and a very great loss to all of us who knew her—as a mother, relative, co-worker, colleague, role model, and heroine—or those who admired her determination to make the world a peaceful, healthy, and better place for all of us," said Karanja Njoroge, executive director of the Green Belt Movement.

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Born in Nyeri, Kenya, on April 1, 1940, Maathai blazed many trails in her life.

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She was the first woman in East and Central Africa to earn a doctorate degree. In December 2002, she was elected to Kenya's parliament with an overwhelming 98% of the vote.

She was honored by Time magazine in 2005 as one of 100 most influential people in the world. And Forbes listed her as one of 100 most powerful women in the world.

In April 2006, France bestowed its highest honor on her: the Legion d'Honneur.

Kenyan President Mwai Kibaki called Maathai a "global icon who has left an indelible mark in the world of environmental conservation."

Her passing elicited tributes from all around the world, like one from U.N. Secretary-General Ban Ki-moon in which he described her as "a pioneer in articulating the links between human rights, poverty, environmental protection and security." He noted that she'd been active in his organization, including as a U.N. Messenger of Peace and part of a group trying to formulate global millennium development goals.

Achmat Dangor, the executive director of the Nelson Mandela Foundation, recalled a 2005 speech that she made before his group in which she laid out specific steps that citizens, governments and businesses could take to protect the environment.

"We need people who love Africa so much that they want to protect her from destructive processes," Maathai said then. "There are simple actions we can take."

British Foreign Secretary William Hague called the passing of the "charismatic figure ... a great loss to the world," and fellow environmental activist and former U.S. Vice President Al Gore recalled her as a woman who "worked tirelessly (to become) a true inspiration for us all."

And U.S. President Barack Obama said that Maathai's life-long fight continues, building off what she was able to accomplish and the minds and policies she was able to shape over her lifetime.

"As she told the world, 'We must not tire, we must not give up, we must persist,'" Obama said in a statement. "Her legacy will stand as an example to all of us to persist in our pursuit of progress."

Maathai leaves behind three children and a granddaughter.