Abstract: Passive rewilding, an emerging concept in restoration ecology, typically involves the cessation of management in plantations. This transition eliminates both fertilizer inputs and biomass harvest, yet whether nutrient retention after harvest cessation offsets fertilizer loss remains unclear. We investigated carbon (C), nitrogen (N), and phosphorus (P) dynamics in Moso bamboo (Phyllostachys edulis) forests across four rewilding durations (0, 10, 20, and 30 years), tracking growth of more than 4,000 culms. We quantified nutrient concentrations, stoichiometric traits, and nutrient stocks in four tissues (leaves, twigs, stems, and roots) of both young (1-year-old) and mature (2- to 9-year-old) bamboo, soil, and microbial biomass. Contrary to the expectation of nutrient depletion, long-term (30-year) rewilding increased total bamboo biomass (+161%) and C, N, and P stocks by 165%, 242%, and 379%, respectively (P < 0.05); soil C, N and P pools also increased by 78%, 79% and 94%, respectively (P < 0.05). The coefficient of variation in stoichiometric traits revealed that nutrient variability declined in young bamboo (homogenization) but increased in mature bamboo (divergence), consistent with young bamboo drawing from a shared clonal nutrient pool while mature bamboo accumulated reserves. Path analysis identified mature stem nutrients as the strongest biotic predictor of total bamboo biomass (P < 0.01). These findings reveal two pathways sustaining productivity in rewilded forests: soil nutrient enrichment following harvest cessation, and internal nutrient redistribution from mature to young bamboo, enabling bamboo forests to transition from fertilization-dependent to self-sustaining nutrient regime, with implications for managing abandoned plantation forests globally.

Key words: Forest rewilding, Plant-soil-microbe stoichiometry, Nutrient redistribution, Land abandonment, Productivity