South Africa’s largest city proudly notes that it has one of the world’s largest urban forests. But an invasive insect has been killing Johannesburg’s trees by the tens of thousands, and baffled experts are scrambling to find ways to stop it.
By Adam Welz • October 16, 2018
Johannesburg has an estimated 6 to 10 million trees, mostly non-native species brought in from around the world. AP Photo/Denis Farrell
“You don’t notice the dead trees until you start looking for them, and then you realize just how many there are,” says Hilton Fryer, a data science consultant. He’s talking about dead trees in Johannesburg, the hustling metropolis that began life in 1886 as a ragtag collection of gold mining camps staked out along the Witwatersrand hill range in the high-altitude grasslands of central South Africa. There weren’t many native trees here — a few found shelter from natural fires in hillside ravines — and once it became clear that area’s gold deposits were the largest ever found anywhere and would deliver up riches for generations, people literally began to put down roots. One by one, they planted trees along the streets, among the houses, and in the parks of the exploding new city, which is still growing…