A little piece of paradise is buried under the asphalt that is now lined with parked cars. The romantic spot where Sosthène Hugues Ngono used to bring his first dates had been green and beautiful. “It wasn’t just a park,” he says, standing at the edge of what is now a private car park in Cameroon’s capital, Yaoundé.

“It was where I came to clear my head when things felt confused,” he says. “Where I met people; where I fell in love, more than once.”

Ngono, 36, a mathematics teacher, watched in dismay as the public park in Essos, a densely populated neighbourhood of Yaoundé, was razed in February last year, but his loss was only a small, personal version of a larger one playing out across the city.

Green space in Yaoundé is under mounting pressure from unregulated urban expansion. Yaoundé covered nearly 33 sq miles (85 sq km) in 1984.…