A Physiognomic Classification of Australian Rain Forests

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Abstract
Australian Rain forests are given the status of 3 formations: Tropical, Subtropical and Temperate (including Cool and Warm facies). These terms follow established usage but connote properties of the vegetation without climatic implications. The boundaries of eastern Australian Subtropical Rain forest, which is coastal or sub-coastal, are defined ecologically as approximately 21[degree]S. near Sarina, north Queensland, and 35[degree]S. near Kiama, southern New South Wales. Temperate Rain forest elements are patchily distributed at increasing altitudes from Tasmania (lat. 43[degree]S.) to North Queensland (lat. 16[degree]S.). The Rain forest formations are classified into 12 possible subformations on the basis of exclusively physiognomic and structural features, which include leaf size; height and continuity of tree layers; proportion of evergreen, semi-evergreen, deciduous or araucarian emergents; and prominence of special life forms such as woody lianes and mossy epiphytes. Subtropical Rain forest, under optimal conditions, is characterized by small mesophyll leaf sizes (2025-4500 sq. mm). It is proposed that "notophyll", as an addition to the Raunkiaer system, be used to denote this characteristic leaf size class. Physiognomic nomenclature is used for the subformations to avoid the ambiguities of climatic terms, and is conveniently abbreviated to symbols. Tropical Rain forest includes Mesophyll Vine forest (symbol MVF), Semi-evergreen Vine forest (SEVF), Deciduous Vine thicket (DVT) and probably other sub-formations. Subtropical Rain forest comprises Notophyll Vine forest (NVF), Araucarian Vine forest (AVF), Araucarian (Microphyll) Vine woodland (AVW), Microphyll Vine woodland (MVW) and Semi-evergreen Vine thicket (SEVT). Warm Temperate Rain forest embrances Simple Mesophyll Vine forest (SMVF) and Simple Notophyll Vine forest (SNVF) which are essentially Lower Montane or Montane forms. Cool Temperate Rain forest includes Microphyll Mossy forest (MMF) and Microphyll Mossy thicket (MMT), which are also largely Montane. The nomenclature of forest, woodland and thicket follows definitions by Bread and Fanshawe. The series of subformations within each formation are broadly correlated with gradients of temperature (altitude or latitude), soil properties (moisture, drainage, fertility) and exposure. The sharp ecological segregation of Rain forests from the autochthonous sclerophyll flora is closely related to soil nutrient status (influenced by fire) as well as to temperature and moisture conditions and historical factors. Australian Tropical lowland subformations, together with Beard''s Lower Montane and Montane expressions of the Temperate Rain forest elements, are only roughly equivalent to those described elsewhere. The original montane series of Beard, rather than recent amendments by Richards, seems more appropriate in Australia. Australian Subtropical Rain forest has unique ecological features which may be partly comparable with those of South Brazilian forests, notably those with Parana Pine. A field key to the Subformations is provided.