Kenya mourns death of Nobel peace laureate Wangari Maathai at 71

From a small village to global crusader for women, human rights and conservation: an extraordinary life story has ended

Kenyans mourned the passing of a national hero yesterday after it was announced that the Nobel laureate Wangari Maathai had died of cancer at a Nairobi hospital, aged 71.

Remembered by many in her native country as a fierce human rights campaigner, she was better known internationally for her conservation work. Her remarkable progress from village girl to groundbreaking academic to environmental and women's rights activist was capped in 2004 by becoming the first African woman to win the Nobel peace prize.

The Green Belt Movement, which she founded and which is leading a campaign to plant a billion trees worldwide, led the tributes: "Professor Maathai's departure is untimely and a very great loss to all who knew her – as a mother, relative ... role model, and heroine; or who admired her determination to make the world a more peaceful, healthier, and better place."

Achim Steiner, the head of the United Nations Environment Programme, which Professor Maathai was instrumental in getting headquartered in Nairobi, described her as a "force of nature". "While others deployed their power and life force to damage, degrade and extract short-term profit from the environment, she used hers to stand in their way," he said.

She frequently sought sanctuary at UNEP headquarters during the presidency of Daniel arap Moi, when her public criticism of political torture and land grabs saw her arrested often, and beaten and whipped on one occasion.

Professor Maathai's string of firsts included being the first woman in post-independence Kenya to earn a PhD, and the country's first female head of a university department.

Kenyan politicians with whom she had an often fractious relationship queued up yesterday to offer their tributes. The President, Mwai Kibaki, credited her with paving the way for Kenya's "second liberation" – the restoration of multiparty democracy. The Prime Minister, Raila Odinga, hailed her as a "voice of reason" and "a lady who stood above our artificial divisions of race, tribe and region".

To many of their political predecessors – whose land-grabbing schemes Professor Maathai had thwarted or whose political repression she had resisted – she was known as yule mwanamke – "that woman".

During Mr Kibaki's first term she briefly held a ministerial position, but she fell out with her colleagues after refusing to turn a blind eye to graft and was unseated as an MP.

Ordinary Kenyans flooded social networks yesterday to pay their respects, calling her "Mama Africa" and a "great Kenyan". Many people shared quotations from her work that linked traditional African sayings with modern conservation efforts: "My language Kikuyu and many other African languages do not have a word for desert," remembered one mourner on Twitter.

In 2004 her Nobel prize, which explicitly linked empowerment of rural communities, environmental activism and peace building, took many by surprise. But to her, the connection between peace, rights and conservation had always been obvious. "You cannot protect the environment unless you empower people," she said.

The US writer and environmentalist Mia MacDonald, who helped Professor Maathai with her autobiography Unbowed: One Woman's Story, was with her in Kenya when news of her Nobel prize came through.

"She was on her way to meet constituents in Tatu (in rural Kenya) and all hell broke loose," MacDonald said last night. "But Wangari refused to go back to Nairobi, saying that some people had walked long distances to talk to her and she wouldn't let them down. So we stood there in a field taking calls from all over the world."

Bob Munro, a friend and a former UN expert on development, said: "Like many pioneering environmentalists, she was often accused of being a 'tree-hugger'. Wangari considered that a high compliment. But she also hugged far more people than trees. Most of those she embraced were poor and Wangari mobilised them in an innovative campaign to protect and plant more trees in Kenya and worldwide."

A life in brief

* Born in Nyeri, Kenya, in 1940

* Became the first woman in East and Central Africa to earn a doctorate.

* Started community-based tree planting projects and helped women to plant more than 40 million trees.

* Prominent figure in the campaign to cancel African debt.

* Won the Nobel Peace Prize in 2004, the most significant of dozens of international awards.