Consequences of clear-cutting and drought on fine root dynamics down to 17 m in coppice-managed eucalypt plantations

International audienceImproving our understanding of the spatiotemporal dynamics of fine roots in deep soil layers is of utter importance to manage tropical planted forests in a context of climate change. Our study aimed to assess the effect of clear-cutting and drought on fine-root dynamics down to the water table in Brazilian ferralsol under eucalypt plantations conducted in coppice. Fine roots (i.e. diameter 13 m) and, surprisingly, root mortality remained extremely low whatever the depth and the treatment. Total fine-root biomass in coppice down to 17m depth was 1266 and 1017 gm−2 in +W and −W, respectively, at 1.5 year after the clear-cut and was 1078 gm−2 in NH 7.5 years after planting. Specific root length and specific root area were about 15% higher in −W than in +W. Proliferation of fine roots at great depths could be an adaptive mechanism for tree survival, enhancing the access to water stored in the subsoil. The root system established before clear-cutting provides access to water stored in very deep layers that probably contribute to mitigate the risk of tree mortality during prolonged drought periods when the eucalypt plantations is conducted in coppice after the clear-cut