Abstract Beech wood veneers were plasma treated by a dielectric barrier discharge at atmospheric pressure using compressed air as process gas. Treatment duration was kept constant, whereas the injected discharge power was varied. Subsequently the veneers were milled down to the veneer's half diameter in order to investigate plasma-induced effects within the bulk material. When increasing the discharge power, lowered water contact angle, decreased pH-value as well as increased nitrate content were observed for the bulk of the veneers. Further, XPS-analysis indicated oxidizing effects within the investigated plasma-treated samples. Electrical breakdown inside cavities within the wood bulk material (e.g. vessel elements) was proposed to explain experimental results.