| Abstract: | Rates of weight loss and release of N, P, K, S, Ca, Mg, Na, and Cl from litter of several species in jarrah (E. marginata Donn ex Sm.) forest were measured in relation to site fire history and soil type. Weight loss from leaf litter decreased in the order jarrah > marri (E. calophylla R. Br. ex Lindl.) > Banksia grandis Willd. After 18 months on the forest floor senesced leaves of jarrah, marri and Banksia had lost 45%, 42% and 19%, respectively, of their original weight. Although greatest rates of decomposition occurred on a site burnt 3 y previously by an intense autumn fire and slowest rates on a site which had not been burnt for 8 y, the differences between burn sites were small in comparison with the total weight loss from decomposing litter. The order of release of nutrients from decomposing eucalypt litter was P<N<Ca<S<Mg<Cl<K<Na. There appears to be only slow release of N and P from the litter layer of these forests in the period between successive control burns. Fresh jarrah leaves, which are similar in chemical composition to leaf litter falling after crowns have been scorched by intense fire, decompose rapidly in comparison with senescent leaf tissue. Release of nutrients, particularly N and P, is also more rapid from fresh leaves than from leaf litter. Rates of decomposition of green leaves differed between soil types in the order reddish gravels > dark sandy duplex soil > yellow gravels. These differences may be related to the higher nutrient status of the reddish gravel soils. |
