Johannesburg and the invasion of the borer beetles

I lived nearly a decade in Johannesburg and the three things that make it bearable are the people and the trees. I say this to people sometimes, and they usually say, “And also the money”, but that’s not true. Money brings you to Johannesburg, and sometimes it keeps you there, but it’s the people and the trees that make it bearable.

Whenever I was hosting a visitor to Joburg, especially one coming for the first time, I would make a point of taking them up some high ridge with an outlook to watch their faces as they surveyed that vast green forest of the city, that splendid verdant woodland only sparsely dotted with rooftops and occasional glimpses of road, that rich effulgence of green all lit up with purple in the spring and reds and yellows in autumn. No one expects Joburg to be so wooded, or expects the bowered avenues with their cool green shade on hot summer days. Every home I lived in in Johannesburg had some remarkable tree nearby: yews and cypresses; grand oaks and a Jurassic palm where pigeons made love in the springtime, using the bouncy fronds as an arborial water-mattress; a magnificent Norfolk pine that I watched being struck by lightning and turned to splinters and matchsticks; a spreading gummy pine that dripped sap into my car when I drove a convertible and made it smell like retsina.

No one knows precisely how many trees there are in Joburg – probably around eight million. It’s often called the largest man-made forest in the world, mainly by Joburgers. Before 1886, when gold was found, there were almost no trees at all where Joburg is now, it was rolling grassland with lightning-struck koppies and only occasional copses, and maybe that is what I love most about the trees of Johannesburg – that none of them truly belong precisely there. There are trees from Europe and Asia and the Americas, West Africa and East Africa and elsewhere in South Africa, all immigrants who came to this strange high dry ridge, sinking roots deep or shallow, creating a canopy above and a web below, fighting and settling and making do, quarreling and cooperating, working together to make a home in a hard place.

The have benefits less metaphorical: they lower the temperature and counter the urban heat-island effect; they scrub the air for us to breathe: the mental and physical health benefits provided to Londoners by their trees has been valued at around 130 million pounds a year. Joburg has about the same number of trees as London, so call that 2.3 billion rand.

I love the trees of Joburg, the way they soften the edges and interstices of an ungentle world, the way still stand even as the society and the concrete around them changes, and it makes me sad that right now they’re being stalked by a seemingly unstoppable serial killer.

If the trees are all glorious immigrants, it’s sadly appropriate that they’re the target of another one. The Polyphagous Shot Hole Borer is a minute beetle from Vietnam who may have come into the country, as Adam Welz suggests in an excellent article for Yale Environment 360, burrowed into the tasty soft wood of packing crates arriving in Durban harbour from south-east Asia.

It’s an unpleasant beetle, as ugly as Ringo, as mean as a drunken John, as undiscriminating as Paul. It has been found in as many as 60 different varieties of tree, burrowing tunnels through the wood to create space in which to grow its food, the fusarium fungus, which in turn blocks the passage of water and nutrients, causing the branches and leaves to die off. Welz estimates that as many as 100 000 trees in Johannesburg have already died, and that some millions more will die over the next ten years, mainly in the suburbs but also dooming recent tree-planting initiatives to green the townships and urban areas.

The beetle is all over Johannesburg and radiating out from it, and has been identified at various other places along the truck path from Durban. It may be elsewhere, and it’s unclear that anything can stop it. There are deep-injection treatments but the chemicals aren’t available here and are prohibitively expensive. The beetle has no natural predators in southern Africa, so of course someone has suggested importing its natural enemy, a species of parasitic wasp from Vietnam. Does any story that begins with importing a parasitic wasp ever end well? Cut to twenty years’ time, when we are importing Japanese Godzilla monsters, the only natural predator of Komodo dragons, the only natural predator of the flying two-headed snakes that were the only natural predators of the red-fang spiders that we imported to control the parasitic wasps.

But still, despite all this, I believe the trees will be all right. Life is better when you believe in something, and you may as well believe in nature. I believe that nature will find a way, that the trees will endure. And if nature doesn’t find a way then people will, because that is one of the things that living for nearly a decade in Johannesburg teaches you: you have to believe in trees, and in people.

The Times, 1 November 2018