Fine root dynamics and partitioning of root respiration into growth and maintenance components in cool temperate deciduous and evergreen forests

Aims We aim to show the seasonality of fine root dynamics and examine the relationship between root respiration (R-r) and fine root dynamics. In addition, we try partitioning R-r into growth (R-g) and maintenance (R-m) components. Methods Soil respiration (R-s), fine root biomass (B), and fine root production (P) were measured simultaneously over a growing season in adjoining deciduous (DF) and evergreen (EF) forests. The R-r was separated from R-s by the trenching method, and R-r was partitioned into R-g and R-m using an empirical model. Results The seasonality of P was almost the same in both forests, though that of B was different. The R-r showed a positive correlation with P in both sites. Annual R-r was estimated to be 610 (DF) and 393 (EF) g C m(-2) year(-1). Annual R-g and R-m were 121 and 166 (DF), and 86 and 182 (EF) g C m(-2) year(-1), respectively. Conclusions We found a clear seasonal pattern in P and a positive linearity between R-r and P. Despite considerable uncertainty due to the small sample size, presence of larger roots, and measurement uncertainty, the results suggest that our approach is capable of partitioning R-r.