Background and aims: Fine root multi-element stoichiometric coupling is essential to maintain terrestrial ecosystem functions. Although forest conversion has been a major driver globally in recent decades, its effect on multi-element stoichiometric coupling remains poorly understood. Methods: This study examined the ratios of fine root N or P relative to exchangeable cations (i.e., K, Ca, and Mg) along a chronosequence of secondary forests and Chinese fir plantations (5 to 41 years old) with reference to primary forests in subtropical China. Results: On average, the ratios of live root N or P to exchangeable cations of plantations were higher than those of secondary forests, and the live roots N:Ca and N:Mg ratios in plantations were also higher than those of primary forests. The dead root N:K and P:K ratios of plantations were higher than those of secondary forests, while the dead root N:K, N:Ca, and N:Mg ratios of plantations and secondary forests were lower than those of primary forests. The ratios of live root N or P to exchangeable cations did not vary remarkably with stand age within plantations and secondary forests, except for the P:K ratio. However, the dead root N:Ca ratio increased with stand age for secondary forests and plantations. Overall, the live and dead root N:Mg, P:K and P:Mg, or N:K ratios decreased with soil depth. Conclusion: Our findings suggest that intensive forest management impairs fine root multi-element stoichiometric coupling in reference to primary forests and stand development has strong influences on fine root multi-element absorption and resorption. [ABSTRACT FROM AUTHOR]