ACCESSION AND DECOMPOSITION OF LITTER IN SPOTTED GUM FORESTS

Abstract

The accession and decomposition, of litter was studied in spotted gum (Eucalyptus maculata Hook) stands on the south coast of New South Wales during 1963 and 1964. The average annual litter accession varied from 3,210 lb/ac in a stand of very small saplings, to 6,102 lb/ac in a virgin, overmature stand. The average annual litter accession for spotted gum stands in the study area was estimated to be approximately 5,000 lb/ac. The components of litter accessions in order of magnitude were: leaves, bark, twigs, and fruiting parts. The greatest accessions occurred in summer. Peak leaf fall preceded peak bark shed which occurred abruptly in the period January-February. The amount of twig fall was relatively small and fairly constant throughout the year. Litter samples equivalent to 7,000 lb/ac, exposed in three stands for 72 weeks lost 2,300 to 2,900 lb/ac through decomposition. The highest rate of decomposition occurred during the first 36 weeks. The rate of litter decomposition varied between stands with different understoreys; irt stands with Macrozamia and Acacia understoreys the rate was greater than in the stand with practically no understorey. Rates of litter accession do not appear to be balanced by equivalent rates of decomposition. This situation may result in an accumulation of litter on the forest floor unless other factors such as fire also are involved.