Characterisation and delineation of the eucalypt old-growth forest estate in Australia: A review

A review of the literature suggests that the definition of the ecological characteristics of old-growth Douglas-fir forests in the Pacific North-West of the United States has influenced the development of definitions and delineation of old-growth forests world-wide. Disturbance at many spatial and temporal scales is a feature of most old-growth forests. Recent disturbance does not, by itself, suggest that a forest has lost all of the characteristics of an old-growth stand. The dynamics of old-growth forests operate on time scales that are slow relative to the time scale of human observation, and they may appear to be static. Fundamental research into the ecological characteristics of old-growth Australian forests is scarce. The lack of basic information will hamper attempts to adequately define old-growth forests. The limits placed on old-growth forest under interim definitions must be shown to bound other potential ecological definitions. Some recent work on Australian old-growth forests suffers from a lack of information on the quantitative relationship between attributes on aerial photographs and other ecological attributes of old-growth forest. There is a need to demonstrate that thresholds used in the delineation process are ecologically sound. The use of fire perimeter records alone to exclude forest from old-growth delineation will lead artificially to a constantly diminishing estate. The old-growth estate is an ecological concept that includes all forest that has the potential to develop old-growth values. It provides for the maintenance of the full array of regeneration stages necessary to conserve the ecological processes and species diversity that characterise old-growth forests. A general prescription for the delineation of the old-growth estate is made. The delineation of the old-growth estate is an issue that should be held separate from the issue of adequate levels and means of protection.