Seed ecology and successional status of 27 tropical rainforest cabinet timber species from Queensland

Abstract

Tropical rainforest seed ecology is diverse reflecting great variation in patterns of germination. These patterns reflect reproductive strategies designed to optimise the distribution and successful germination of species. The percentage germination varied widely across the 27 rainforest species. An additional seven species failed to germinate under the conditions provided and are not discussed further. When grouped according to successional status, in the absence of seed pre-germination treatments, germination on average reached 53% in late secondary species, 61% in early secondary species, 71% in climax species compared to only 17% in the pioneer species. The time to onset of germination was significantly lower in pioneer species (5 ± 9.9 days) compared to early secondary (14 ± 7.6 days) and climax (35 ± 7.5 days) successional species. We imposed eight pre-germination treatments, of which each was effective in increasing germination percentage for at least some of the trialed species. The most effective pre-germination treatments were nicking and boiling water, which gave on average five to sixfold increases, respectively, as compared to darkness and the presence of fleshy fruit or combinations thereof of those treatments. The knowledge of germination ecology may enable nursery operations to accurately plan seedling production.