Effects of Light, Moisture, Temperature, and Litter on the Regeneration of FiveTree Species in the Tropical Montane Wet Forest of Puerto Rico

摘要

Field experiments were conducted to investigate the effect of light, moisture,temperature, and litter on the regeneration ot two early-, one mid-, and two late-successional tropical tree species. High light and litter seem to be universally good cues for regeneration, increasing seed/seedling survival for all species except for Cecropia (an early-successional species) whose small seeds may not be able to penetrate the litter layer. In addition, the high temperature environment in both artificially shaded and nonshaded area of a natural gap exhibits less seed loss, an increase in the percent and rate of germination, and an increase in seedling survival for Darcryodes (a late-successional species), than the lower temperature environment under an intact canopy. Low soil water is also a good cue for Dacryodes germination as it is for Prestoea and Cecropia. Finally, the lower temperature environment found under the forest canopy (compared to the natural gap) leads to less seed loss and more germination for Guarea (a mid-successional species). Our results suggest that a good patch for regeneration of many species