The Effect of a Teak (Tectona grandis) Plantation on the Establishment of Native Species in an Abandoned Pasture in Costa Rica

background

This study compares native tree species recruitment in the understory of a 10-year-old teak plantation in premontane wet forest in Costa Rica to the native tree species recruitment on nearby abandoned agricultural land.

Research Goals & Methods

The data were taken from 42 transect plots in both sites and included the species, location, and height of all woody species as well as the percent crown closure. The diversity of the regeneration in the two sites was calculated using Simpson’s index of biodiversity and Fisher’s index of alpha diversity.

Conclusions & Takeaways

The density of woody recruits was found to be much higher in the transects of the abandoned pasture. Nearly all (89.9%) of the native species recruits in the teak plantation were within the lowest height class, while about half (51.4%) of native recruits in the abandoned pasture were within the lowest height class. Within the teak plantation, the taller height classes were almost exclusively dominated by teak. Species diversity was calculated to be much higher in the abandoned pasture as well; 61 tree species in 31 families were identified in the abandoned pasture, compared to 26 species and 14 families in the plantation. The set of species identified in the teak plantation was dominated by trees with shrubby growth forms while larger monopodial trees were more common in the pasture. Crown closure in both sites was found to be similar. The authors conclude that teak impedes native tree species recruitment and, thus, has little secondary value as a nurse crop for incoming native seedlings.