Seedling Recruitment in a Native Tree Plantation in the Lowland Tropical Rainforests of Costa Rica

Abstract

In a continuation of a preexisting reforestation project, we examined the recruitment of seedlings in plantation plots of varying light (shade vs. sun) and cultivation (monoculture vs. polyculture), in the lowland tropical rainforest of Costa Rica. The treatment plots primarily had canopies of Pentaclethera macroloba (Fabacae), the most common tree in the area, planted in a 3x3 meter grid. However, four other species were planted interspersed with P. macroloba in the polyculture lots and unplanted adults were present in the shade plots. The intention of the project was to gain insight into forest recovery and succession, in terms of density, species richness, and diversity, once reforestation plots had been left idle. All seedlings with a basal diameter greater than 1 cm were censused for their species, locations, and overhead canopy densities. There were no significant differences in species richness or diversity based on either treatment or cultivation. Density differed only in treatment (P<0.01), where mean density was greater in shade plots (85.625???) than in sun plots (51.312???) and not in cultivation. However, despite the lack of significant difference in diversity and richness, the abundance of three of the top four most prevalent species was significantly different for at least one of the two factors. This study helps to illuminate some of the potential for successional populations after plantation restoration efforts.