And when he had set the brands on fire, he let them go into the standing corn of the Philistines, and burnt up both the shocks, and also the standing corn, with the vineyards and olives. (Judges 15:5)
The low vines of the grapes and the dry trunks of the olive trees would burn easily. Samson was probably not fully aware of the extent to which the conflagration he was starting would grow. When the fires were over, miles of blackened fields were all that remained where the day before were rich harvests.