Archaeologist: Neanderthals, a human-like species living 60, 000 years ago, probably preserved meat by smoking it. Burnt lichen and grass have been found in many Neanderthal fireplaces. A fire of lichen and grass produces a lot of smoke but does not produce nearly as much heat or light as a wood fire.
In the region containing the Neanderthal fireplaces in which lichen and grass were burnt, no plants that could be burned more effectively to produce heat or light were available 60, 000 years ago would most weaken the archaeologist's argument.