Fine root-soil interactions fundamentally affect the terrestrial carbon (C) cycle and thereby ecosystem feedbacks to climate change [1]. Fine roots act as conduits of carbon transfer, from plants to soils, and as agents of nutrient acquisition and transport. In parallel, they are the source of secondary metabolites, i.e., the drivers of rhizosphere development and of the root-facilitated C cycling in forest soils. Beyond that, growth, death, and decomposition of fine roots are key processes that occur continuously and simultaneously throughout the whole year, and stocks of living (biomass) and dead fine roots (necromass) represent the end-products of these processes. Furthermore, along different natural climatic zones, trees have evolved contrasting growth and survival strategies for their fine roots to adapt to the tremendous variations in seasonal climates [2,3]. It was found that standing root biomass varied by over an order of magnitude across plant biomes, and the highest root biomass in terrestrial plant biomes was observed in tropical forests [4]. Thus, modeling responses of different forest ecosystems to global changes can benefit greatly from a better characterization of the fine rootstock patterns and dynamics [5] and, consequently, of the carbon transfer into the soil in different forest biomes across the world.
