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

Abstract

We aim to show the seasonality of fine root dynamics and examine the relationship between root respiration (Rr) and fine root dynamics. In addition, we try partitioning Rr into growth (Rg) and maintenance (Rm) components. Soil respiration (Rs), 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 Rr was separated from Rs by the trenching method, and Rr was partitioned into Rg and Rm using an empirical model. The seasonality of P was almost the same in both forests, though that of B was different. The Rr showed a positive correlation with P in both sites. Annual Rr was estimated to be 610 (DF) and 393 (EF) g C m−2 year−1. Annual Rg and Rm were 121 and 166 (DF), and 86 and 182 (EF) g C m−2 year−1, respectively. We found a clear seasonal pattern in P and a positive linearity between Rr 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 Rr.