Mulching does not improve seedling survival or growth during early forest restoration

Abstract Introduction Weed control is one of the main operational challenges and cost components of tropical forest restoration in former pasturelands. Physical barriers (mulches) have been proposed as an alternative to conventional ring weeding because they can suppress competing vegetation while potentially improving the soil microenvironment. However, their ecological and economic benefits remain poorly understood. Objectives This study evaluated whether different ring‐weeding techniques improve early seedling establishment and provide alternatives for controlling invasive grasses in tropical forest restoration. Methods A randomized complete block design was established using four ring‐weeding techniques (bare‐soil control, litter mulch, geotextile mulch, and cardboard mulch) with five replicates. Each experimental plot contained the same assemblage of 30 native tree species. Seedling survival, height and stem diameter increments, soil temperature, soil moisture, and implementation costs were evaluated over 187 days. Results All ring‐weeding techniques effectively suppressed competing vegetation. However, mulching did not improve seedling survival or growth compared with conventional ring weeding. Geotextile mulch resulted in lower stem diameter increment than the other treatments. Although litter mulch, cardboard, and geotextile reduced maintenance frequency, their economic performance differed substantially. Litter mulch combined low implementation costs with high operational efficiency, whereas cardboard and geotextile involved substantially higher implementation costs without providing measurable gains in seedling performance. Conclusion Although the evaluated mulching materials successfully suppressed competing vegetation, they did not provide measurable advantages in seedling establishment over conventional ring weeding during early forest restoration.