Fine root dynamics after soil disturbance evaluated with a root scanner method

Fine root production in ecosystems has been estimated mainly by excavation methods that cause soil disturbance. In this study, patterns of fine root dynamics following soil disturbance were monitored for multiple years and were analyzed quantitatively by applying a root scanner method that allows continuous observations. Eleven scanners were inserted into the soil of cypress and oak forests with soil disturbance, and weekly soil profiles were scanned for several years. Then fine root dynamics were estimated quantitatively by image analyses. Fine roots emerged intensively in the immediate year of the scanner installation. Seasonal patterns of cumulative root area production followed the logistic curve, but its parameters varied depending on stands and elapsed years after the scanner installation. Estimates of the annual production and instantaneous production rate from the logistic equation differed between the immediate and the following years after disturbance in the cypress and oak stands. The root scanner method is a viable technique to quantitatively describe fine root dynamics of forests, including the possible effects of soil disturbance. The results suggested that fine root production can be described by a logistic equation providing both an asymptotic upper boundary and a growth coefficient.