楼主说的白桦其实是silver birch(Betula alba)，是常说的birch bud，和其他的black birch, yellow birch(Betula lenta, Betula alleghaniensis)是不同的哟。birch bud是northern europe的，while the other two are native to North America. F master is right about this again, birch bud is a good diuretic for use in cellulite, so are the other two. As to analgesic effect, black and yellow birch are rather superior.

我也是纸上谈兵，其实从来没有过这个油。。