Litterfall and the Standing Crop of Litter in Three Tropical Australian Rainforests

Abstract

Results of litterfall and the standing crop of litter are presented for 3 contrasting rainforest sites on similar soils but with different climatic regimes in northeastern Queensland, Australia. Annual litterfall varied between sites and ranged from 728 g m-2 yr-1 to 1053 g m-2 yr-1 over a period of 3 yr and at all sites. Litterfall is strongly seasonal and the heaviest falls occurred in the latter part of the dry season and the early part of the wet season. Between-year variation in total litterfall was low and 3-yr coefficients of variation within sites ranged from 4.5-10.0%. The proportions of leaf, fine woody material, and of flowers, and seeds were assessed for 14 mo. and related to the characteristics of the forests. Seasonal, annual and between-site variation in the standing crops of litter was marked. The minimum standing crop at the most mesophytic sites was approximately 300 g m-2, the maximum recorded was in excess of 1050 g m-2. The relative proportions of leaf, wood, and of flowers, fruits and seeds in the standing crop of litter were assessed for 14 mo. and varied seasonally and between sites. Total and leaf litterfall values from the world tropics are related to site latitude, altitude and precipitation.