Oddly, concrete burns better than you’d imagine and the right pressure-treated lumber burns far less easily than you’d imagine. There’s a big movement to use lumber in the sort of construction long dominated by concrete and rebar
I misstated this: Concrete BUILDINGS burn better than you’d imagine. The concrete doesn’t actually burn; it just crumbles into dust while everything AROUND it burns. The crumbling allows the fire to move through a building.