From the link: "The best trees are found at higher mountain elevations of over 1000 meters, typically on northern exposures where nutrient-poor soil and a cool climate promote a short growing season."

Interesting, that. I was wondering how they would go about finding a sustainable source for knot-less timber.

Knots come from where branches tie in to the tree trunk. In good soil and with good growing conditions - reliable production of rain and enough sunshine and warmth- branches will grow close to the ground, will begin forming in the tree trunk very early in its development.

So, a tree suitable for musical instruments and fine cabinetry will be a tree that has survived despite poor growing conditions.

I didn't know that. Makes me think of a guitar differently.