South Amazon forests have been highly deforested since the 1970’s. The Y Ikatu Xingu watershed campaign direct seeded 5 000 ha of forests from 2006 up to 2018. Direct seeding is considered a feasible, inexpensive, and effective method for ecological restoration with advantages that facilitate large-scale use, such as mechanized operations. Nevertheless, little is known about the successional trajectory of tropical forests restored through direct seeding. We sampled 72 direct seeded sites (1-10-y old), three seedling planted sites, and six natural regeneration sites, along a latitudinal gradient of 600 km in the state of Mato Grosso, Brazil. Sites began dominated by herbs and shrubs (green manure, short cycle leguminous), followed by 1 to 5 light-demanding tree species, while slow-growing species were present in the understory. After four years, direct-seeded sites formed a multi-layered canopy and were starting to be colonized by non-planted species. We sampled 90 species from the 152 seeded plus 68 colonizer species. Seeded communities present more orthodox, wind-dispersed seeds than reference forests. However, animal-dispersed and recalcitrant seed traits are found in colonizers. Canopy frequently closed (80%), forming a tall secondary forest with high height-to-diameter ratio trees that do not bifurcate in the first 3 years. Broadcast seeding sites had higher seedling and sapling densities than sites that received other restoration methods. In conclusion, direct seeding was a successful method for tropical forest restoration, promoting a structure that was more like resilient natural regeneration sites than to non-resilient natural regeneration sites and seedling planting sites.
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Society for Ecological Restoration