Influence of Thermal Modification in Nitrogen Atmosphere on Physical and Technological Properties of European Wood Species with Different Structural Features

The wood of five European species: black poplar (Populus nigra L.), beech (Fagus sylvatica ash (Fraxinus excelsior oak (Quercus robur and Scots pine (Pinus sylvestris L.) was subjected to thermal modification in nitrogen atmosphere at 190 °C during 6 h. Native modified varnished oiled industrial conditions. Thermally (TM) characterized by a greater absorption varnish oil when applying the first layer surface, which finally resulted higher application values compared native wood. In particular, after varnishing, there significant increase gloss radical change colour. Regardless species, finishing process (varnishing, oiling), ?E were close or than 6, proves high colour changes. Modified poplar, ash, varnishing had different (?E 12). surface changes as result UV photoaging individual, depending on species method finishing. case thickness coatings, structure important, i.e., ring-porous hardwood softwood they thicker. with lower density, pine, did not reduce resistance coat, density (oak, beech) it decreased one level. Thermal reduced Brinell hardness wide rays (oak 11%. applied double oiling significantly tested