Juniper is good for compresion to so degree. Both the sap and the heart wood. However there are many varieties and some are much denser then others. There are a few varieties that are like balsa wood and junk and some other that are excellent. It takes a book and very carefull examination of the twigs to tell what variety you have. some have only a difference of 1/32 of an inch in the twig diam and minute variances in clusters. Yet even the best juniper is touchy when it comes to very powerfull backing like Bamboo. I once made a bamboo backed juniper that took a very heavy set. it stayed together and though it didn't chrysal it definitely had some crushed cells as evident in the amount of set it took.
The very best backing for Juniper is sinew. It's a light springy wood and the sinew just compliments that without overpowering.
