Studies on the seed biology of 100 native species of trees in a seasonal moist tropical forest, Panama, Central America

This study quantified various aspects of the seed biology of 100 tree species native to the seasonal moist tropical forest in the Panama Canal Watershed. Species were selected for study based on their potential for use in reforestation projects in Panama. Seeds of 32, 29, and 33 species were dispersed during the dry (DS, January-March), early rainy (ERS, April-July), and late rainy (LRS, August-December) seasons, respectively. Seed mass was correlated with moisture content (MC) but not with dispersal time, and MC was lowest for seeds dispersed in the DS. Germination of nontreated seeds ranged from 0% (6 species) to 99% and was >= 50% for 46 species. Seeds of Beilschmiedia pendula, Castilla elastica, Diphysa robinioides, Genipa americana, Hura crepitans, Inga spectabilis, Jacaranda copaia, Protium tenuifolium, Pseudobambox septenatum, and Trattinnickia aspera germinated >= 85%. Fresh seeds of 49 (52.1%) of the 94 species that germinated were nondormant and 45 (47.9%) were dormant. Only 12 species had a median length of germination time (MLG) > 120 days. MLG for seeds of species dispersed in the LRS was higher than that of those dispersed in the ERS or DS. Forty-eight species had uniform germination (standard deviation of germination time <= 14 days). Seed longevity ranged from 0.5 to 36 months, and long-lived (L-L) seeds tended to be larger than short-lived (S-L) or very short-lived (very S-L) ones, but not significantly so. MC increased significantly from L-L to very S-L seeds. The highest proportion of L-L seeds was dispersed in the DS and the lowest in the LRS. Results of this study are used to make recommendations for nursery production of tree seedlings to use in forest restoration projects. (c) 2006 Elsevier B.V. All rights reserved.