Ying Ki Law

and 4 more

Landslides are common in tropical and subtropical regions with hilly terrains and heavy rainstorms, which cause significant economic, ecological, and social impacts. Natural forest succession is usually slow on landslide scars due to poor soil structure and the lack of seeds of woody plant seeds, and often comes with a higher risk of repeated landslide. Ecological forest restoration has recently been suggested as an effective alternative to restore the exposed landslide scars, however, a comprehensive study to identify effective landslide restoration strategies remains lacking, particularly associated with seed treatment methods and species selection. Here we evaluated the effectiveness of different seed coating treatments of both pioneer and later successional tree species of different seed sizes on seed germination in a one-year study on three landslides in Hong Kong. Our results show that bare seeds had germination rates of 17 to 67% across all selected species (n=7). Biochar-dominant seed coating formulation boosted an additional 9.33 (SE= 0.04) in seed germination rate, while the clay-dominant seed coating formulation did not show significant effect on germination. Our results also show that medium and large-seeded non-pioneer species have significantly higher germination rates than pioneer species. These results collectively suggest that direct seeding using a biochar seed coat is a manageable and useful method to enhance tree seed germination—an essential first step to restore the forests after landslide disturbances in Hong Kong, with potential to be extended to other humid tropical and subtropical forests.