In forest ecosystems, the belowground biomass accounts for 13–25 % of the stand biomass, 2–15 % consisting of fine roots. A substantial fraction of net primary productivity in forested ecosystems is exported belowground to produce ephemeral fine roots. Despite their relatively minor contribution to the overall root biomass, fine-root turnover represents up to 33 % of the total annual net primary production in most ecosystems. Therefore, fine-root dynamics is widely recognized as an important biogeochemical process in forest soils. Very fine (d<0.5 mm) and fine (0.5<d<2 mm) roots represent the most dynamic component of a root system and they comprise the majority of the length and water/nutrient absorbing surface area of a root system. Furthermore, fine roots are characterized by a rapid turnover which is influenced by a variety of internal (e.g. genotype of plant species) and external (e.g. temperature, precipitation, soil properties, nutrient availability and competition between plants) factors. Thus, fine-root dynamics set limits on shoot functioning by assuring the maintenance of plant productivity even under water deficit. Given their simple anatomical organization, fine roots are also the most sensitive component within the overall root system and, thus, respond rapidly to variations occurring in the rooting environment. The research on fine-root topic evaluate the relationship of plant roots with environment paying particular attention to abiotic stress such as water, fire and mechanical.