I gather from your post it has to be a natural substance and not synthetic? I would suggest Chinese cedar oil, which is smoky, Virginia cedar which is sort of pissy, angelica root oil is also a good choice, you would dilute it first. I am opposed personally as a perfumer to using natural musk or civet due to animal cruelty. If you could go with synthetics, I would suggest Symrise's Aldron and Galaxolide as well as the above. Also a synthetic ambergris that is excellent is called Ambroxan and is available in small quantities at www.thegoodscentscompany.com All these things would soak into wood nicely if you mixed them into alcohol. The alcohol will evaporate off quickly.