From the second book of Samuel, here’s this, in the King James version:
“So the people went out into the field against Israel: and the battle was in the wood of Ephraim; Where the people of Israel were slain before the servants of David, and there was there a great slaughter that day of twenty thousand men. For the battle was there scattered over the face of all the country: and the wood devoured more people that day than the sword devoured.” — Second Book of Samuel, chapter 18, verses 6 through 8
A note on the verse says the Hebrew text has “multiplied to devour;” so the trees multiplied to devour the enemies of King David. And of course then the trees got Absalom, David’s son and leader of the rebellion.
In Tolkien’s The Two Towers, the orcs fleeing into the forest from the battle at Helm’s deep, are destroyed by the trees.
Tolkien was a serious linguist and scholar, and translated the Book of Jonah for the Jerusalem Bible. I wonder if the Wood of Ephraim was in his mind as he wrote about Fangorn Forest?