If you’re seeing neat rows of trees on the Thai Southern Line, and its not oil palm, its probably rubber trees. They’re amazing.
The tree is not particularly remarkable to look at. It can grow to a hight of around 43 metres, but the plantations don’t usually let them get that big because the younger trees produce more latex. The latin name, Hevea Brasiliensis, gives away that it is not local to this part of the world, but mesoamerica, where people had been producing rubber as early as 1600BC.
To make rubber, the trunk of the rubber tree is cut at around 30-degrees in a spiral working up from the bottom, where a cup is placed to collect the milky latex sap as it oozes out of the trunk. This is then mixed with formic acid to coagulate and harden into a semi-solid state, and then pressed through a ringer in a similar way you might make sheets of pasta. This creates a bathmat-sized flap of what looks disturbingly like skin. You might see these hanging out to dry on racks as you steam past rubber estates.
These collected latex skins can then be “vulcanised” – or heated with sulphur to create a polymer that can be strong and durable enough to make a good, say, ice hockey puck, bowling ball, tractor tyre, or stilleto heel. But it can also be chemically manipulated to be plyable enough to be a swimming cap, bungee cord, or balloon.