Natural Stands

Melaleuca alternifolia (family Myrtaceae), commonly known as Australian tea tree, is native to eastern Australia. Its natural distribution is mainly confined to the coastal watercourses

of northern New South Wales (NSW) and the 'granite belt' of southern Queensland (Figure 1). Isolated populations extend south to Port Macquarie and northwest to Stanthorpe, 31°30'S and 28°30'S respectively (Butcher et al. 1994). The majority of natural stands grow in the flood plains of the Richmond and Clarence river systems. The range of altitude of M. alternifolia is 1-60 m in NSW for the two river systems and up to 800m in southeast Queensland where the species is found near Ballandean and Stanthorpe.

The species grows in warm subhumid conditions. In this climatic zone, the mean daily maximum temperature during mid summer is 27-31 °C and the mean daily minimum temperature during mid winter is 5-7°C. Frosts occur infrequently, on average 1-3 per

Figure 1 The distribution of Melaleuca alternifolia (after Byrnes 1986)

year. The Ballandean-Stanthorpe area has, however, an average of 51 frosts per year. Rainfall for the Richmond and Clarence catchment areas ranges from 1000 to 1600mm annually. Rainfall occurs predominantly in summer with a relatively dry spring.

Native stands are generally found on soils with a pH (measured in water) of 4.5-5.5 (Colton and Murtagh 1990) and a soil texture that ranges from sandy clay loam to heavy clay loam (Small 1981). These soil types in the watercourses and low lying areas of northern NSW are often swampy. M. alternifolia is tolerant of long periods (1-3 months) of inundation and even short periods (less than a week) completely immersed in flood waters (Colton and Murtagh 1990).

The natural form of M. alternifolia is a single stemmed paper bark tree with a clear bole for one to two thirds of the tree height (up to 15m). Branch habit is mainly ascending and the crown broad (Plate 2).

Commercial quantities of oil from natural stands of M. alternifolia have been produced for over 50 years. Mature trees are harvested manually, leaving stumps about one metre high. Branches are trimmed and the foliage is taken for steam distillation. The cut stumps coppice vigorously (Plate 9) and the new regrowth is then harvested on a regular basis. The annual oil production of about 30t from natural stands is limited by the restricted distribution of M. alternifolia, the small size of individual stands and poor accessibility of the resource particularly in the wet season. Oil production from stands in state forests is also dependant on licences issued by State Forests. Any restrictions to these licences will reduce future oil production from natural stands.

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