Woods come in a wide variety of hardness. If your preference is for harder wood and your favorite noter isn't quite there, you may be able to improve its density at the tip by compressing it. This requires some practice or you may crush the wood instead of compressing it. I use a small shop vice and only squeeze about one half inch of the tip of my noters. I tighten the vise on them gently and try to never over tighten. I make my own noters so it's not a great loss if I go too far. This will work on round noters, but then you may have trouble turning it so that the compressed portion addresses the string(s) of your dulcimer. Done properly, you can even see the results. The wood will look shiny where you've compression hardened it. This practice will not only give a little more 'ring' to the sound of your strings, it will lessen wear just a little. The wood won't groove as badly as quickly if it is harder. Try this on some scrap. It may be something you like.
Again, I would caution you NOT to do this on your favorite wooden noter for your first attempt. Try this several times on scrap or old discarded noters to develop a 'feel' for it.
--
The Dulcimer. If you want to preserve it, jam it!