This menacing security force was more than a match for its opponents: 12 women, most of them elderly, and six members of the Kenyan Parliament, armed only with tree seedlings, gardening tools and watering cans. Maathai and her followers wanted to plant trees in the forest to reclaim it symbolically for the public. When she saw the force arrayed against her inside the gate, catcalling and bellowing threats, she told her group, "These thugs are spoiling for trouble, and the police will not protect us. Let's plant one tree outside the gate and leave."

As Maathai picked up a 60-cm Meru oak seedling and moved toward the gate, more than 100 of the armed men surged out of the forest and began beating the demonstrators with whips and clubs. One powerfully built young man struck Maathai on the back of the head, and she fell to her knees under a hail of whips, with blood seeping from a scalp wound. Six women rallied around her, carrying her through a gauntlet of attackers to a waiting car, which drove a kilometer to a police station. The officers showed no interest in investigating the assault, but Maathai insisted on filing a complaint, signing it with blood from her wound. She was then taken to Nairobi Hospital, where doctors stitched her head and kept her under observation for three days. Altogether 10 of the protesters were injured, three of them seriously. From her hospital bed, Maathai declared, "As soon as I recover, I shall return to Karura forest, even if they bury me there."