Fine root dynamics is one of the important components in forest carbon cycling in tropical forests. The minirhizotron method is now a widely used technique for monitoring fine root biomass, production, mortality. This method allows us to observe root behavior directly without destruction, but it is difficult to scale up the results to stand level because of the small observation windows. Also, most of the image analysis are performed manually, which may yield insufficient quantitative and objective data. Recently, scanner method has been proposed, which can produce much bigger-size images (A4-size) with lower cost than those of the minirhizotron methods. However, laborious and time-consuming image analysis still limits the applicability of this method. In this study, therefore, we aimed to develop a new protocol for scanner image analysis to extract root behavior in soil. We applied our new protocol to analyze temporal changes of root behavior from sequential scanner images derived from a Bornean tropical forests. The results detected by the six observers showed considerable concordance in the abundance and the growth of fine roots but less in the decomposition.