Edaphics and Fire: An Interpretative Ecology of Lowland Forest Vegetation on Granite in Northeast Tasmania F. Duncan and M.J. Brown (Communicated by D. Keith) Duncan, F. and Brown, M.J. Edaphics and fire: an interpretative ecology of lowland forest vegetation on granite in northeast Tasmania. Proc. Linn. Soc. N.S.W. 115: 45-60(1995) Forest, scrub and moorland vegetation near Old Chum Dam in northeast Tasmania is described. Analyses of the floristics and some environmental variables suggest that moisture availability, drainage and edaphic factors have a major influence on vegetation composition and structure. The vegetation itself, largely through differences in the flammability of its understorey, encourages fire frequencies and intensities which maintain its current heterogeneity. Trends observed in the study area are similar to those reported from comparable forested areas in Tasmania and on the southeastern Australian main-land. F. Duncan and M.J. Brown, Forestry Tasmania, 1 99 Macquarie Street, Hobart, Tasmania 7000; manuscript received 16 August 1994, accepted for publication 19 April 1995. KEYWORDS: vegetation, ordination, classification, edaphic, fire, Northeast Tasmania. Introduction The vegetation of a forested area near Old Chum Dam, in northeastern Tasmania, was surveyed in March 1990 as part of a wider study into the effects on the biota of forestry operations and forest conservation prescriptions. The vegetation is representative of that occupying much of the forested lowland country in the Northeast. There are few published descriptions of lowland vegetation in northeastern Tasmania, though the upland vegetation has been documented more thoroughly (e.g. Ellis, 1985; Davies and Davies, 1989). Remnant heaths, forests and woodlands occurring on the Great Northern Plain, to the north of the study area, are described (Kirkpatrick and Wells, 1987) , and forest vegetation on Spurrs Rivulet, to the east of the study area, has been analysed (Peters, 1984). Stephens and Cane (1938) and Pinkard (1980) provide general descriptions of the vegetation of northeastern Tasmania, and its relationship with the environment. Statewide analyses of major vegetation types (e.g. Kirkpatrick, 1977; Jarman et al, 1984; Duncan and Brown, 1985; Kirkpatrick et al, 1988; Jarman et al, 1988; Pannell, 1992) include forest and non-forest communities found in the Northeast. Species nomenclature in this paper follows Buchanan etal. (1989). The Study Area The study area consists of undulating country in the upstream catchment of the Great Musselroe River, in the vicinity of Old Chum Dam (41°06'S 148°03'E). The general location is shown in Figure 3. Altitude varies from 100m to 250m above sea level. The area occurs within the humid warm climatic zone defined by Gentilli (1972). Average annual rainfall at Pioneer, some 9km to the west of Old Chum Dam, is 978mm and has a pro-nounced seasonality. January is the driest month (mean monthly rainfall of 45mm) and July the wettest (mean monthly rainfall of 112mm). Temperature records are available Proc. Linn. Soc. n.s.w., 115, 1995
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