Modelling surface fine fuel dynamics across climate gradients in eucalypt forests of south-eastern Australia

摘要

An understanding of the eff ects of climate on fuel is required to predict future changes to fi re. We explored the climatic determinants of variations in surface fi ne fuel parameters across forests (dry and wet sclerophyll plus rainforest) and grassy woodlands of south-eastern Australia. Infl uences of vegetation type and climate on fuel were examined through statistical modelling for estimates of litterfall, decomposition and steady state fi ne litter fuel load obtained from published studies. Strong relationships were found between climate, vegetation type and all three litter parameters. Litterfall was positively related to mean annual rainfall and mean annual temperature across all vegetation types. Decomposition was both negatively and positively related to mean annual temperature at low and high levels of warm-season rainfall respectively. Steady state surface fi ne fuel load was generally, negatively related to mean annual temperature but mean annual rainfall had divergent eff ects dependent on vegetation type: i.e. positive eff ect in low productivity dry sclerophyll forests and grassy woodlands versus negative eff ect in high productivity wet sclerophyll forests and rainforests. Th e species composition of the vegetation types may have infl uenced decomposition and steady state fuel load responses in interaction with climate: e.g. lower decomposition rates in the low productivity vegetation types that occupied drier environments may be partially due to the predominance of species with sclerophyllous leaves. Th e results indicate that uncertain and highly variable future trends in precipitation may have a crucial role in determining the magnitude and direction of change in surface fi ne fuel load across south-eastern Australia.