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The aim of this chamber experiment was to study the single and interaction effects of warming (+2 degrees C increase), moderate nitrogen (N) addition (30 kg N.ha(-1).year(-1)), and bark herbivory by large pine weevil (Hylobius abietis L.) on fine root morphology, mycorrhizas, root phenolics, and biogenic organic volatile compounds (BVOCs) from the rhizosphere area of young Scots pines (Pinus sylvestris L.). Warming increased soil exploration by increasing specific root length (SRL) and the relative proportion of 0.2-0.3 mm roots in fine root systems, while N addition and herbivory without warming both caused an increase in the relative proportions of thicker roots in the fine root systems. Warming decreased total phenolic concentrations in the roots without N addition, while some flavonoid compounds showed complex responses to warming, N addition, and herbivory. Nitrogen addition in combination with warming reduced the total emissions of other BVOCs from the rhizosphere area at the end of the experiment. Herbivory increased mycorrhizal colonisation rates and had a tendency to reduce total emissions of other BVOCs from the rhizosphere area four weeks after the weevil damage. Based on the above results, all of the factors studied have the potential to affect the fine root morphology and chemical defence in young Scots pine seedlings.