Multi‐year studies comparing changes in litterfall biomass and nutrient inputs in sites under different restoration practices are lacking. We evaluated litterfall dynamics and nutrient inputs at 5 yr and after a decade of recovery in four treatments (natural regeneration—no planting, plantation—entire area planted, tree islands—planting in patches, and reference forest) at multiple sites in an agricultural landscape in southern Costa Rica. We inter‐planted two native species (Terminalia amazonia and Vochysia guatemalensis) and two naturalized N‐fixing species (Inga edulis and Erythrina poeppigiana) in plantation and island treatments. Although litterfall N was higher in plantations in the first sampling period, litter production and overall inputs of C, N, Ca, Mg, P, Cu, Mn, and Fe did not differ between island, plantation, or reference forest after a decade; however, all were greater than in natural regeneration. Potassium inputs were lower in the natural regeneration, intermediate in island and plantation, and greater in reference forest. The percentage of litterfall comprised by the N‐fixing planted species declined by nearly two‐thirds in both plantations and islands between sampling periods, while the percentage of V. guatemalensis more than doubled, and the percentage from naturally regenerated species increased from 27 to 47 percent in islands. Island and plantation treatments were equally effective at restoring litterfall and nutrient inputs to levels similar to the reference system. The nutrient input changed substantially over the 7‐yr interval between measurements, reflecting shifts in vegetation composition and demonstrating how rapidly nutrient cycling dynamics can change in recovering forests.

Active restoration strategies increase the production of leaf litter in tropical forests, but little is known about their effect on litter decomposition and subsequent nutrient release. We quantified changes in leaf litter stoichiometry during decomposition in former pasture sites under contrasting restoration strategies (natural regeneration, applied nucleation/islands tree planting and plantation), as well as in nearby primary forest. Litterbags were employed to evaluate decomposition. We used a leaf mixture of either the four planted tree species in the plantation and island treatments or the nearby primary forest and compared them under a factorial design. Decomposition rates were similar between restoration treatments (p > 0.5), but leaves decomposed faster in the forest mixture than in the plantation mixture (p < 0.01). The content of Ca, Mg, K, P, and the C:N ratio were higher in the forest mixture at the beginning and during decomposition (p < 0.05); the N content in the plantation mixture was higher at the beginning but lower during decomposition (p < 0.05), which meant greater mobilization of nitrogen per unit of carbon lost. K and P had a strong initial release, while Mg was released more gradually. N and Ca had an irregular pattern of initial fast release, immobilization, and re-release in the later stages. We conclude that the differences in rates of decomposition and nutrient release in these systems under restoration were at least partly determined by the floristic heterogeneity and chemical quality of the leaf litter that reaches the soil.

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