'Forest' in the Bible

Joshua said to them, "If you are a great people, go up to the forest, and clear land for yourself there in the land of the Perizzites and of the Rephaim; since the hill country of Ephraim is too narrow for you."

but the hill country shall be yours. Although it is a forest, you shall cut it down, and it's farthest extent shall be yours; for you shall drive out the Canaanites, though they have chariots of iron, and though they are strong."