The olive was a major cash crop and trade good for the ancient Athenians, and it helped their rise to power considerably. The possibility that the trees would get destroyed, as well as the decision to defend the limited land Athens had, might have been a factor in the decision to fight at Marathon. While the Achaemenids were pushed back, what I am curious about is what if, during the invasion, the Achaemenids committed economic sabotage and destroyed the trees, laid more waste to the land, and gutted much of the Athenian economy through this action? The trees the Athenians grew took a very long time, and they were quite delicate. How would this affect Athenian politics at the time? Does the wall still get built after the Persians leave? Does Athens still become dominant? What happens with the Ionian cities?