This has been bugging me for years, but not enough for me to get around to actually finding out the answer.
When you buy DAR (dressed all round) softwood, it typically comes with faint grooves running the length of the timber. (These are about 1mm apart).
Other than the possibility it is used to identify soft wood from hard, why are the grooves there, and how are they produced? Grooved blades on the thicknesser I assume. But to what benefit?
One brand is laserwood, but these days if you google that, all you get are countless ads for laser engravers!