Mizue Ohashi1, Hidetoshi Ikeno2, Kotaro Sekihara3, Toko Tanikawa4, Masako Dannoura5,6, Keitaro Yamase7, Chikage Todo7, Takahiro Tomita8, Yasuhiro Hirano3. 1. School of Human Science and Environment, University of Hyogo, Himeji, 670-0092, Japan. ohashi@shse.u-hyogo.ac.jp. 2. School of Human Science and Environment, University of Hyogo, Himeji, 670-0092, Japan. 3. Graduate School of Environmental Studies, Nagoya University, Nagoya, 464-8601, Japan. 4. Kansai Research Center, Forestry and Forest Products Research Institute, Kyoto, 612-0855, Japan. 5. Graduate School of Global Environmental Studies, Kyoto University, Kyoto, 606-8501, Japan. 6. Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan. 7. Hyogo Prefectural Technology Center for Agriculture, Forestry and Fisheries, Shiso, 671-2515, Japan. 8. School of Engineering, University of Hyogo, Himeji, 671-2280, Japan.
Abstract
MAIN CONCLUSION: We developed simple algorithms for reconstructing tree root system architecture using only the root point coordinate and diameter, which can be systematically obtained without digging up the root systems. Root system architecture (RSA) is strongly related to various root functions of the tree. The aim of this study was to develop a three-dimensional (3D) RSA model using systematically obtained information on root locations and root diameters at the locations. We excavated root systems of Cryptomeria japonica and systematically obtained XYZ coordinates and root diameters using a 10-cm grid. We clarified the patterns of the root point connections and developed a reconstructed root system model. We found that the root diameters farther from the stump centre are smaller. Additionally, we found that the root lengths of the segments running between the base and the connected root point were smaller than those of other root segments, and the inner angle between the base and the stump and between the base and the connected root point was narrower than for the other pairs. The new RSA model developed according to these results had average accuracies of 0.64 and 0.80 for estimates of total volume and length, respectively. The developed model can estimate 3D RSA using only root point data, which can be obtained without digging up root systems. This suggests a wide applicability of this model in root function evaluation.
MAIN CONCLUSION: We developed simple algorithms for reconstructing tree root system architecture using only the root point coordinate and diameter, which can be systematically obtained without digging up the root systems. Root system architecture (RSA) is strongly related to various root functions of the tree. The aim of this study was to develop a three-dimensional (3D) RSA model using systematically obtained information on root locations and root diameters at the locations. We excavated root systems of Cryptomeria japonica and systematically obtained XYZ coordinates and root diameters using a 10-cm grid. We clarified the patterns of the root point connections and developed a reconstructed root system model. We found that the root diameters farther from the stump centre are smaller. Additionally, we found that the root lengths of the segments running between the base and the connected root point were smaller than those of other root segments, and the inner angle between the base and the stump and between the base and the connected root point was narrower than for the other pairs. The new RSA model developed according to these results had average accuracies of 0.64 and 0.80 for estimates of total volume and length, respectively. The developed model can estimate 3D RSA using only root point data, which can be obtained without digging up root systems. This suggests a wide applicability of this model in root function evaluation.