h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

We've some old plane trees planted in the oldest part of town, where the main post office and some other important places are. They're quite big by now and really lifting up the pavement all around them. I do hope they're not removed!

Play music at them to make them stop, if they threaten to move them.

Planes are the only trees capable of flight.

Heh heh Paulh we have helicopter trees here as well!

http://pza.sanbi.org/gyrocarpus-americanus-subsp-africanus

Dmitri, they won't move them, they'd just take them out!

Gyrocarpus americanus (Helicopter tree" is not native to the U.S., but it is native to Mexico.

It occurs widely in South America also, and in Africa, Asia and Australia! This is called a pan-tropical distribution, and one way to try to explain it, is that its seeds are able to survive immersion in salt water so that they can be spread around by the ocean and wash up on tropical beaches where if all goes well some of them germinate. But the ones we have here are found far inland in a rather dry and barren part of the country. They're very drought-resistant.

Ah, but dry parts of Africa have not always been dry. For instance, the Sahara was once a lush rainforest. Perhaps the trees you find inland in dry places are descended from plants that once lived in wetter surroundings.