North of the Eyre Highway in the South-East part of West Australia, there is a line of trees with desert on all sides. There is no visible river.

Why is this the case?

enter image description here

-31.8985239 S, 127.135608 E

  • 3
    $\begingroup$ Please add a link with the coordinates. $\endgroup$
    – user28185
    Mar 14, 2023 at 16:18
  • $\begingroup$ Looks more like an elevation change than excessive trees. On Street View, looks like nearer the coast there's modest coverage of trees/bushes in most spots, nothing excessively distinct about that line, except the elevation change? $\endgroup$ Mar 14, 2023 at 16:42
  • $\begingroup$ Thanks; Any particular reason why the elevated area may have more trees? (I'm assuming more rainfall due to orographic uplift?) $\endgroup$
    – aman
    Mar 14, 2023 at 16:59

1 Answer 1


These trees lie on the south-facing downward slope of an escarpment separating the Hampton Tableland (the southern part of the Nullarbor Plain) to the north from the Roe Plains to the south.

As the name "Nullarbor Plain" suggests, the area is very dry, but this little amount of slope allows for a slightly wetter microclimate, just enough to grow some scrub and a few trees on the slope.

  • 1
    $\begingroup$ Thanks; out of curiosity, can you explain why the south-facing slope has a wetter microclimate? $\endgroup$
    – aman
    Mar 15, 2023 at 2:43
  • 2
    $\begingroup$ @aman: The approximate difference in elevation between the two plains is 80 m. The predominant wind direction is from the south. The escarpment captures winds from Antarctica. As the air goes over the escarpment it will have a tendency to drop moisture making the escarpment & its base wetter. Also, that part of the world is well south of the Tropic of Capricorn, so the Sun is always in the northern part of the sky, so parts of the escarpment will sometimes be in a shadow, hence slightly cooler than the two plains; hence the micro-climate. $\endgroup$
    – Fred
    Mar 15, 2023 at 11:37

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