Fine-root Production and Turnover in a Willow Plantation Estimated by Different Calculation Methods
Fine-root production and turnover were estimated in a short-rotation stand of basket willow (Salix viminalis L.) in central Sweden. Different calculation methods, based on soil coring, or combinations of soil coring and minirhizotron technique, were used. Fine-root biomass production and mortality in the 0-50 cm soil horizon were estimated at 900-7200 kg ha-1 yr-1 and 500-6800 kg ha-1 yr-1, respectively, depending on the method used. Corresponding values for production and mortality of fine-root length per unit soil volume were 160-1600 dm dm-3 yr-1 and 40-1500 dm dm-3 yr-1, respectively. Methods based on soil coring alone gave the lowest estimates, and probably underestimated production and mortality, since both processes to a high degree occurred simultaneously in the willow plantation. Thus, this study emphasizes the necessity to separate the processes of growth and decay where high fine-root turnover occurs.