AUSTRALIA — Some reports have argued that extensive areas of Australia’s forests were kept open through frequent burning by First Nations people. Advocates for widespread thinning and burning of these forests have argued that fire is needed to return these forests to their “pre-invasion” state. A key question then is: what does the evidence say about what tall, wet forests actually looked like 250 years ago? …In a new paper, we looked carefully at the body of evidence. Our analysis shows most areas of mainland mountain ash forests were likely to have been dense and wet at the time of British invasion. The large overstorey eucalypt trees were relatively widely spaced, but there was a dense understorey. …The evidence we compiled all indicates mountain ash forests were dense, wet environments, not open and park-like. …Based on this evidence, we should not be deliberately burning or thinning these forests.