In a village on the slopes of Mount Kenya in East Africa, a little girl worked in the fields with her mother.

The girl's name was Wangari.

Wangari loved being outside.

In her family's food garden she broke up the soil with her machete.

She pressed tiny seeds into the warm earth.

Her favourite time of day was just after sunset. When it got too dark to see the plants, Wangari knew it was time to go home.

She would follow the narrow paths through the fields, crossing rivers as she went.

Wangari was a clever child and couldn't wait to go to school. But her parents wanted her to help them at home.

When Wangari was seven years old, her big brother persuaded her parents to let her start school.

Wangari liked to learn. She learnt more and more with every book she read.

She did very well at school, and was invited to study in America.

Wangari was excited! She wanted to know more about the world.

At the American university Wangari learnt many new things. She studied plants and how they grow.

And she remembered how she grew: playing games with her brothers in the shade of the beautiful Kenyan forests.

The more she learnt, the more she realised that she loved the people of Kenya. She wanted them to be happy and free.

The more she learnt, the more she remembered her African home.

When she had finished her studies, she returned to Kenya.

Huge farms stretched across the land. Women had no wood to make cooking fires.

People were poor and hungry.

Wangari taught the women how to plant trees from seeds, and how to look after the seedlings.

The women sold the trees and used the money for their families.

The women felt powerful and strong. And many trees grew.

As time passed, the trees grew into forests, and this helped the rivers to start flowing again.

Wangari's message spread across Africa. Today, millions of trees have grown from Wangari's seeds.

Because of her work for the environment and people, Wangari won a famous international prize, called the Nobel Peace Prize.

In 2004, Wangari Maathai was the first black African woman ever to receive the Nobel Prize, and also the first environmentalist.

Wangari died in 2011, but we can think of her every time we see a healthy tree.

We can continue her work by planting and looking after our forests.