Standing fine root mass and production in four Chinese subtropical forests along a succession and species diversity gradient

BACKGROUND AND AIMS: The influences of succession and species diversity on fine root production are not well known in forests. This study aimed to investigate: (i) whether fine root biomass and production increased with successional stage and increasing tree species diversity; (ii) how forest type affected seasonal variation and regrowth of fine roots. METHODS: Sequential coring and ingrowth core methods were used to measure fine root production in four Chinese subtropical forests differing in successional stages and species diversity. RESULTS: Fine root biomass increased from 262 g·m⁻² to 626 g·m⁻² with increasing successional stage and species diversity. A similar trend was also found for fine root production, which increased from 86 to 114 g·m⁻² yr ⁻¹ for Cunninghamia lanceolata plantation to 211–240 g·m⁻² yr ⁻¹ for Choerospondias axillaries forest when estimated with sequential coring data. Fine root production calculated using the ingrowth core data ranged from 186 g·m⁻² yr ⁻¹ for C. lanceolata plantation to 513 g·m⁻² yr ⁻¹ for Lithocarpus glaber – Cyclobalanopsis glauca forest. CONCLUSIONS: Fine root biomass and production increased along a successional gradient and increasing tree species diversity in subtropical forests. Fine roots in forests with higher species diversity exhibited higher seasonal variation and regrowth rate.