The types of vegetation depend on the climatic zone, not from the continent.
In Tunisia, several climatic zones: subtropics (where palm trees are one of them, is much more northerly than the area of combat that is in the game).

In the game, combat takes place in the semi-desert (arid), in the floodplain of the river. Those. There will be marshes, cacti, vegetation predominantly narrow-leaved and with needles.

You probably confuse these places, with the coast of Libya. There really is often palm trees and sand. But Libya this is not Tunisia.