Background/Question/Methods The projected increase in temperature accompanied by frequent drought imposes severe abiotic stress to plants. Plants exhibit morphological and physiological plasticity to adapt to these stresses. These environment-driven plastic responses are often accompanied by chemical plasticity, which includes changes in the quantity, composition, and localization of heteropolymers (e.g., lignins and tannins). Fine roots (diameter ≤ 2mm) of trees adapt to their soil environment through changes in root morphology and physiology, which is relatively well studied. However, the associated changes in root chemistry are less known. The chemistry of roots also regulates their decomposition that recycles nutrients in senesced tissues and facilitates ecosystem productivity. This talk will focus on exploring the diversity and dynamics of small molecules and oligomers in fine root orders as a function of stress treatment and the associated ectomycorrhizal colonization. Results/Conclusions The chemical plasticity regarding the quantity of heteropolymers is relatively well known. However, the biological activity of heteropolymers such as lignins and tannins is mostly driven by their composition than by their quantity. Chemical plasticity also encompasses the change in the localization of these hetero polymers. Besides changes in the quantity of heteropolymers, and environmental stress such as a drought can alter the composition and localization of these heteropolymers. In fine roots, these stress induced changes can also very with different root orders based on their absorptive or transport function. The talk will highlight recent research on the effect of drought on lignins, tannins and bound phenolics in the fine root orders of trees and will discuss the uniqueness in fine root chemical construct in maximizing the resource uptake functions while concurrently adapting to unfavorable biotic and abiotic soil conditions.