Frankincense, a tree-derived aromatic resin, is particularly redolent during the holidays. Last year, scientists warned that Boswellia, the frankincense tree, could be facing extinction. In the holiday tradition, however, there is hope. This year, botanists may have discovered the trick to sustainable harvesting, and increasing the tree's numbers. Meanwhile, an Arizona-based Boswellia horticulturalist is offering starter trees in an online shop!