I am currently a student at the Violin Making School of America in Utah and I have a few questions regarding Resin/Rosin/Sap as it applies to making from-scratch natural wood varnishes for our musical instruments. Now I know you all may not be master wood workers or organic chemists as well as conifer experts, so I'm only asking for any guidance you can offer from your own respective fields. For instance, have there been any studies regarding the differences between various species of tree and their resin/sap components? Or what about the sustainable harvesting techniques of sap from different species (I've read that some coniferous shrubs have more sap in their buds than in their "trunk")? Or maybe you could tell me specifically what not to do :-). I may not even be asking the right questions at all here, so any guidance would fall on appreciative ears.
P.S. I am aware of the many articles written on violin varnish that have been written in the past, I'm looking for more fresh-perspective, recent-studies type information. You know, what's going on with conifers these days? :-D