Modified pine with no coating from left to right at 3, 6, 9, 12 and 18 months, at 45° facing south in Vienna. Reference sample (left), weathered sample (right) a untreated wood (reference) b acetylated wood c cr-free salt-impregnated wood d thermally treated wood e furfurylated wood
Image credit: Holzforschung Austria / Grüll