What did it used to look like? A case study from tall, wet mainland Mountain Ash forests prior to British invasion

There has been extensive commentary about historical First Nations' land management in Australia, including in tall, wet forests, and therefore their condition at the time of the British invasion in 1788. Popular texts have interpreted records kept by early British invaders to argue that extensive areas of tall, wet forest were kept open through frequent burning by the First Peoples. However, these interpretations conflict with historical and ecological evidence, which is rarely acknowledged in public discourse. Here, we present evidence about what Victorian Mountain Ash (Eucalyptus regnans) forests were like at the time of the British invasion. We show that at the time of the British invasion, most areas of mainland Mountain Ash forests were likely to have been naturally dense and wet, with: (1) overstorey trees spaced relatively widely; and (2) an understorey consisting of a cool temperate rainforest mesic layer. Ecological and physiological evidence suggests that Mountain Ash forests evolved under conditions where high-severity wildfire was comparatively rare, leading to patterns of landscape-level cover dominated by relatively mature forests. This is broadly consistent with reports from the First Peoples, early historical accounts, paintings, and photographs. These forests were not open or park-like, as may have been the case in some other Australian vegetation types. However, these forests were not wilderness, but places of significance to the First Peoples. Understanding forest structure at the time of the British invasion is critically important in establishing historical reference conditions for guiding appropriate restoration programmes, especially the reinstatement of traditional ecological knowledge, after long periods of post-British invasion disturbance and degradation. Notably, the dense, wet understorey that characterizes Mountain Ash forests should be recognized as an inherent and entirely natural part of the ecological dynamics of this ecosystem, with approaches to thin, burn, or remove it highly likely to be counterproductive and have a range of detrimental environmental effects.