In this thesis, we analysed the surface of spruce (Picea abies (L.) Karst.) wood after treatment with dielectric barrier discharge (DBD) plasma and subsequent surface coating. We used transparent colourless coatings (solvent- and water-borne) and a more environmentally friendly agent (tung oil). It is known that the aesthetic and physical properties of wood (eg. colour, gloss, adhesive strength, defects) are negatively affected by the exposure of surfaces to weather and environmental influences. By determining the contact angles on treated and untreated surfaces, we studied the influence of changing treatment parameters on the wettability of wood. After exposure to external conditions, the samples were monitored over time periods of one, three, six months and at the end of the test (after 10 months). The results showed that the plasma treatment of wood decreased the degree of contamination of coated surfaces, exposed in exterior, with biotic factors, and indirectly it had a positive effect on the penetration depth of the coatings, but did not have such significant effect on the colour, gloss of surfaces and adhesion of coatings.