If you want as much detail as wood grain then SketchUp is not the best format to go to that level of detail, as Eric says it better to get one already made and print directly from .stl or another format rather than converting it into SketchUp.
If you want as much detail as wood grain then SketchUp is not the best format to go to that level of detail, as Eric says it better to get one already made and print directly from .stl or another format rather than converting it into SketchUp.