Effects of litter from a tropical rainforest on tree seed germination and establishment under controlled conditions.

The effects of litter cover on the germination of seeds of three tropical rainforest, pioneer tree species (Cecropia obtusifolia, Heliocarpus appendiculatus and Piper auritum) was investigated. Germination of seeds of all tree species was partially or totally inhibited when the seeds were covered with litter, whereas uncovered seeds or seeds covered with paper instead of litter germinated. Seed size was directly correlated with the capacity of the germinated seeds to emerge through the litter. In soil experiments in the greenhouse, seedling emergence from the soil was inhibited by the presence of litter on the soil surface.