University of Tasmania, Australia

We will discover how fire activity has varied over the last 10,000 years around the Southern Hemisphere. Our focus is in western Tasmania where there is a widespread occurrence of two species of fire-sensitive endemic Tasmania conifers in the genus Athrotaxis that live for over 1000 years and form distinct annual tree rings. Landscape ecology analyses of the distribution of living and dead trees will disclose the geographic pattern of past fires and tree ring analyses provide enable the dating fires over the last thousand years. Surrounding Athrotaxis stands are numerous small lakes that have captured macroscopic charcoal and nutrients released from fires over the last 10,000 years. Combining these data means we can reconstruct fire histories for western Tasmania. We will compare these findings with similar studies we are conducting in New Zealand and South America enabling us to see how fire activity is influenced by climate variability, human settlement patterns, and different floras. We will determine if fire activity is synchronistic around the Southern Hemisphere and evaluate the claim that climate change is causing increased fire activity. Such knowledge is crucial for ecologically sustainable fire management, resolving debates about past Aboriginal environmental impacts and understanding the risks posed by climate change.

Why is the study centred on Western Tasmania? This region is a unique natural laboratory to study landscape fire in Australia for the following reasons: (a) nearly all the natural vegetation remains uncleared, and much is conserved in a World Heritage Area; (b) the landscape is made up of a mosaic of fire sensitive and fire tolerant plant communities; and (c) unlike any other region in Australia, there is an abundance of high quality historical data because of the widespread occurrence of long-lived (>1000 years) trees with proven dendrochronological capability, and thousands of small lakes and tarns that have high resolution Holocene sedimentary records.

A key aspect of this project is the quantification of the land-use switch from Aboriginal to European and their influence on fire regimes over the last 200 years. As in most areas worldwide, including Tasmania, European fire regimes resulted in the widespread destruction of long unburnt and fire-sensitive vegetation, including large tracts of endemic Tasmanian conifers.

This project capitalizes on the strong environmental gradients in central Tasmania, including vegetation, soil, hydrology and human land use, as well as watersheds that contain multiple small lakes and wetlands suitable for paleoecological investigation. Analysis of the landscape-scale variability in fire activity will help elucidate the role of biotic and abiotic controls on local fire activity. This information will aid efforts to interpret of charcoal-based fire-history records at larger spatial and longer temporal scales, providing an important link between tree-ring studies and charcoal-based Holocene reconstructions.

This project is built around an ARC grant that is linked to a NSF PIRE grant (http://www.wildfirepire.org/) looking at southern hemisphere fire activity. It brings together some of the leaders in the field of dendro-fire ecology, southern hemisphere forest dynamics, fire regime reconstruction from lake sediment analyses.

Members (External)

Prof David Bowman, david.bowman@utas.edu.au

Prof Cathy Whitlock, Department of Earth Sciences, Montana State University, MT, USA

Prof Thomas Veblen, Department of Geography, University of Colorado, CO, USA

Dr Samuel Wood, samuel.wood@utas.edu.au

Dr Michael Fletcher, College of Asia and the Pacific, Australian National University

Dr Simon Haberle, School of Culture, History & Language,  Australian National University

Dr Andrés Holz, andres.holz@utas.edu.au

Mr Scott Nichols, Bowman's Lab Manager, School of Plant Science, UTAS