During impregnation, wood is colored green by the copper-containing preservative we use. In places where resin is present in the wood, this manifests in the form of green spots and the formation of salt crystals. This is common and occurs in all impregnated wood. After being exposed to the sun for a few weeks, the spots will disappear. After this has occurred, it's possible to stain the wood, if desired. Tip: Lightly sand any severely affected areas.
