Spatial and temporal patterns of root dynamics in a Bornean tropical rainforest monitored using the root scanner method
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Root phenology patterns in tropical regions are poorly understood because limited data are available. Using the root scanner method, the aims of this study were to clarify 1) the temporal phenology of root production and decomposition, 2) the spatial variability of the root phenology, and 3) the contribution of different root diameter classes to root production and decomposition.
Image acquisition was conducted monthly from April 2014 to May 2015 at five sites in a Bornean tropical rainforest. The projected area and length of root production and decomposition were derived manually from images using image-processing software and were grouped into 0.5-mm-diameter intervals.
The spatial distribution of root production and decomposition differed among the sites. Monthly projected root length indicated that the number and timing of peak root production and decomposition differed with each site. A substantial proportion of root production and decomposition was dominated by very fine roots (<0.5 mm diameter).
The scanner method was useful to monitor the root phenology at the root system scale though the scanner images cover only a portion of the root systems of mature trees. Different patterns of root phenology among the sites might be associated with the high diversity and the indistinct seasonality of the Bornean tropical rainforest.
KeywordsFine root Very fine root Root phenology Root production Root decomposition Aseasonal tropical rainforest
We are grateful to the Forest Department, Sarawak, for their kind support of our research in Lambir Hills National Park. The authors greatly appreciate the effort taken by R. Yamauchi, University of Hyogo, for data acquisition. We would also like to thank Dr. T. Kimura, University of Hyogo, for assistance with image analysis. We thank Catherine Dandie, PhD, from Edanz Group (www.edanzediting.com/ac) for editing a draft of this manuscript. We would like to thank Dr. K. Matsumoto for the valuable comments on the manuscript. Data used in this paper are available from the corresponding author upon request. This study was financed in part by Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan (Nos. 25304027, 16H02762). MO, TK, AK, NM designed the study, and IE wrote the initial draft of the manuscript. LKK contributed to acquisition of data. IE, MO, TK, NM, HI and JI contributed to analysis and interpretation of data, and assisted in the preparation of the manuscript. All other authors have contributed to data collection and interpretation, and critically reviewed the manuscript.
- Guo D, Li H, Mitchell RJ, Han W, Hendricks JJ, Fahey TJ, Hendrick RL (2008) Fine root heterogeneity by branch order: exploring the discrepancy in root turnover estimates between minirhizotron and carbon isotopic methods. New Phytol 177:443–456. https://doi.org/10.1111/j.1469-8137.2007.02242.x CrossRefPubMedGoogle Scholar
- Ishizuka S, Tanaka S, Sakurai K, Hirai H, Hirotani H, Ogino K, Lee HS, Kendawang JJ (1998) Characterization and distribution of soils at Lambir Hills National Park in Sarawak, Malaysia, with special reference to soil hardness and soil texture. Tropics 8:31–44. https://doi.org/10.3759/tropics.8.31 CrossRefGoogle Scholar
- Kume T, Ohashi M, Makita N, Kho LK, Katayama A, Endo I, Matsumoto K, Ikeno H (2018) Image analysis procedure for the optical scanning of fine-root dynamics: errors depending on the observer and root-viewing window size. Tree Physiol 38(12):1927–1938. https://doi.org/10.1093/treephys/tpy124 CrossRefPubMedGoogle Scholar
- Metcalfe DB, Meir P, Aragão LEOC, da Costa ACL, Braga AP, Gonçalves PHL, de Athaydes Silva Junior J, de Almeida SS, Dawson LA, Malhi Y, Williams M (2008) The effects of water availability on root growth and morphology in an Amazon rainforest. Plant Soil 311:189–199. https://doi.org/10.1007/s11104-008-9670-9 CrossRefGoogle Scholar
- Najar A, Landhäusser SM, Whitehill JGA, Bonello P, Erbilgin N (2014) Reserves accumulated in non-photosynthetic organs during the previous growing season drive plant defenses and growth in Aspen in the subsequent growing season. J Chem Ecol 40:21–30. https://doi.org/10.1007/s10886-013-0374-0 CrossRefPubMedGoogle Scholar
- Nakagawa M, Tanaka K, Nakashizuka T, Ohkubo T, Kato T, Maeda T, Sato K, Miguchi H, Nagamasu H, Ogino K, Teo S, Hamid AA, Seng LH (2000) Impact of severe drought associated with the 1997–1998 El Niño in a tropical forest in Sarawak. J Trop Ecol 16:355–367. https://doi.org/10.1017/S0266467400001450 CrossRefGoogle Scholar