Boswellia is a genus of trees containing a number of species. Boswellia is most well-known for producing an aromatic resin which can be used to make frankincense. The trees also have a number of medical uses, and are often prescribed by herbalists as an anti-inflammatory.
Most frankincense is graded based on the quality of the resin obtained from the Boswellia. Resin quality is largely determined by when it is harvested, but a great deal of sorting and culling takes place as well, to make sure the grades are correct. Occasionally Westerners and the dealers from the Middle East will differ on the actual quality ranking of different grades. This may be due to local differences in taste, but is likely more often a result of the way different frankincense smells in different temperatures and humidity levels. What might smell best in the dry and hot climate of the Middle East does not necessarily smell best in the wet and cold of England.
The resin of Boswellia is obtained by scraping the bark of the tree and letting the resin ooze out and harden on the tree. The hard lumps that are created are called tears, and the tears are collected, with the earlier tears producing lower-quality frankincense, and the latest tears producing higher-quality frankincense. Most trees will be tapped two or three times a year, and by the third tapping the tears of the Boswellia are extremely high in the various aromatics that make frankincense so prized.
A special grade of frankincense comes from trees that have endured the most extreme hardship. Boswellia have hardy and deep roots, and so can survive on cliff-faces where most of the dirt has been blown away by violent storms. These trees seem to jut straight from the living rock, and it is thought that their hard lives confer healing powers through their tears.
One of the most widespread species of Boswellia is Arabian Frankincense, or Boswellia sacra. Most Arabian Frankincense comes from Yemen and Oman, and the two highest grades are known as Silver and Hojari. Hojari is generally thought to give off the best fragrances in colder climates, while silver is thought to be best in hot climates.
Frankincense has been used in religious rites for thousands of years. It is spoken of in the Old Testament of the Bible, and is perhaps most famous to Westerners as being one of the gifts given by the Magi to Mary and Joseph. The distinctive scent of Boswellia is a staple in many religious ceremonies to this day.
Historically, Boswellia has been used in Ayurvedic medicine in India for millennia. Indian doctors prescribed Boswellia for a wide range of ailments, including arthritis, dysentery, ringworm, diarrhea, and various pulmonary diseases. Boswellia has also been used in Traditional Chinese Medicine, ingested to assist in digestion. Recent studies have also shown that when burned, Boswellia may help reduce stress and depression.