So I somewhat recently acquired a Nordstrand NJ4 Deluxe with a partially spalted fingerboard (spalted sapwood, technically. This might be important to know). In the thread that this bass was being sold in the owner said he didnt see any structural problems with the spalted sapwood, but Im not sure if he noticed that the sound coming out of it varies. When I fret over a piece of sapwood (its about 1/4 of the fretboard higher on the neck), the sound is quite substantially different from when I fret anywhere else. I thought that it might just be because fretting the low E high up on the neck would always sound really different, but then I pulled the string off of that part of the fretboard, onto a non-sapwood part. The sound of the sapwood really brought out the lows and mids, making the sound a decent amount warmer/muddier. Im sure there are at least a few people on these boards with partially sapwood fretboards. Check it out, do you get the same effect? I dont know if its a good thing or a bad thing. Generally I would say that I'd like a uniform tone throughout the neck, but perhaps there is some advantage to having one part warmer than others. In addition, if you bent the string the sound changed, so that could be useful. I just thought it was pretty interesting that the sound difference was so noticeable.