Tropical Forest Restoration: Tree Islands As Recruitment Foci In Degraded Lands Of Honduras

Background

Methods to accelerate forest recovery must address a number of impediments including limits on seed dispersal and microclimactic extremes. This study evaluates the ability of tree islands to serve as recruitment foci for additional seeds in a two-year study in northern Honduras.

Research goals & methods

Islands of three sizes (64 m², 16 m², and 4 m²) were established in pasture at distances of 20m and 50m to secondary forest, containing seedlings of Gliricidia sepium and Bursura simaruba. Open-pasture ‘islands’ of similar sizes served as controls. Tree islands had higher rates of zoochorous seed rain, with greater species richness and seed density than in open pasture. More than 80% of seeds collected were of grasses. Large islands had greater seed density than smaller islands. Similar seed densities were found in a 1m perimeter to the islands, suggesting that islands can expand outwards. Distance to forest did not affect seed rain.

Conclusions & takeaways

Planting seedlings and vegetative stakes to create tree islands in pastures accelerates forest recovery by overcoming a number of impediments, and presents a simple, broadly applicable alternative for facilitating forest regeneration in abandoned pastures.