The Nature of the Boundaries Between Tall Eucalypt Forest and Warm Temperate Rainforest in the Unlogged Compartments of Nullum State Forest in Northeastern New South Wales

Abstract

This study examined the nature of the boundaries between montane wet sclerophyll forests (WSF) and warm temperate rainforests (WTRF) in far northeast New South Wales. The location was Nullum State Forest, a section of which contained approximately 500 ha of forest which, through isolation due to difficulty of access had remained unlogged. This particular forest community was essentially undisturbed and field evidence suggested a fire frequency cycle in the order of over 100 years. Given these conditions, the forest boundaries were considered "natural". The rainforest occurred as small stands of not more than 10 ha while the WSF occurred as larger stands which were interconnected via other types of sclerophyll forest. The WSF was dominated by 'Eucalyptus pilularis' with significant populations of 'Syncarpia glomulifera' and 'Allocasuarina torulosa'. The WTRF patches were variously dominated by 'Ceratopetalum apetalum' or 'Schizomeria ovata' or else a mix of several species. Several transects comprising contiguous 0.1 ha plots were laid down across the study area from WSF patches through the transition zone into WTRF. From within the transects the measured attributes of the boundaries and the adjacent forests included elements of the microclimate, the abundances of all vascular plant species, the forest structure, the litterfall and aspects relating to the dynamics of the boundaries. The results show that the transitional zone is distinct from the wet sclerophyll forest and the warm temperate rainforest, exhibiting features which are absent from those two forest types. Several other measured attributes of the transition zone, however, were found to be mid-way between the values for open forest and closed forest.