In forest ecosystems, root systems represent up to 40% of the biomass, and around 75% of the annual net primary production is allocated to the fine root component (roots with a diameter of less than 2 mm). Fine roots are involved in nutrition, whereas coarse roots (more than 2 mm in diameter) contribute to tree anchorage and stability. Root studies are necessary to understand whether the natural level of root plasticity is able to respond to the foreseen worsening global environmental scenario. In this chapter, the author principally focuses on root turnover and root system architecture parameters describing respectively the plasticity of fine and coarse roots. An example is provided on how the methods used can enable the analysis of tree responses to abiotic stressors such as drought and fire as well as mechanical forces. The concluding remarks highlight the importance of including root research when planning landscape forest restoration of specific sites.