Temporal variations in fine roots, litterfall and soil respiration in a secondary tropical forest of Pahang, West Malaysia.

Plant fine roots C dynamics are often overlooked in terrestrial ecosystem carbon cycle. Fine root production (FrP) is influenced by root decompositions (Frd), necromass (FrN),root biomass (FrB), fine root turnover (FrT) and soil respiration (Rs). Indirect factors such standing litterfall (Lf) and climate (c) also influence FrP. The objectives of the study was to determine how fine root dynamics differ with time (i), the effects of litterfall and soil respirations on fine root dynamics (ii) and finally to assess the effects of climate on fine root dynamics, litterfall and soil respiration. Sequential soil core sampling and the root bag technique were used in a tropical forest at 120 days intervals for two years at Jengka, Pahang, Peninsular Malaysia. The continuous inflow method was used to estimate FrP, FrN, and Frd. Litterfall was estimated using litter traps and Rs using an automated soil CO2 flux system concurrently with root data collection. The litter and fine root stocks were 3.34 and 0.98 Mg C ha-1, respectively. The annual decomposition decay constant (k) was -0.6168 year-1. Fine root dynamics (Frb, Frd, FrN,) differed temporally. Lf correlated with Rs and Frb. Correlations with mean temperatures was recorded for Frd Frb, FrN, and Frd. Total FrP, FrN, Frd, and FrT ranged between 627.80 –791.05 g m-2 yr-1; 854.10 – 704.80 g m-2 yr-1; 585.22 – 511.89 g m-2 yr-1; 0.71 t year-1, respectively. Our results support that temporal estimation of Frb, Frd, Lf, FrN and Rs are needed for understanding belowground carbon allocations.