This study investigates hunter-gatherer responses to environmental change in south-western Australian forests. The study region is the Leeuwin-Naturaliste Region, extreme south-western Australia. It examines how hunter-gatherers reacted to terminal Pleistocene and early Holocene expansions of Karri (Eucalytpus diversicolor) tall open-forest, a forest type identified as difficult to occupy. The putative hunter-gatherer reaction requires careful assessment because past hunter-gatherers could have continued to occupy forested areas by using many different habitats within forests and controlling the extent of unfavourable habitats by firing. The author assesses the issue by reviewing ecological and archaeological research in south-western and south-eastern Australian forests and analysing archaeological evidence for occupation in various types of forest.