Frankincense, also known as olibanum, is an aromatic oleo-gum-resin prized for its use in incense, perfumes, and traditional medicine, a practice extending back thousands of years. It contains essential oils, gum, and resinous compounds. Obtaining frankincense involves stimulating the Boswellia tree to produce its protective sap. This article details the traditional, multi-step procedure of harvesting the resin.
Identifying the Source: The Boswellia Tree
Frankincense is exclusively derived from trees belonging to the genus Boswellia, which includes several commercially important species. The most well-known species are Boswellia sacra (Arabian Peninsula and Africa) and Boswellia serrata (India). These trees are adapted to thrive in harsh, arid environments, often growing on dry, rocky slopes.
The resin is a biological defense mechanism produced by the tree in response to physical damage. When the bark is injured, the tree releases a complex mixture of terpenes, boswellic acids, and polysaccharides to seal the wound and prevent infection. This defensive secretion is channeled through specialized resin ducts within the bark, ready to exude when the outer layer is breached.
The Initial Tapping and Wounding
The process of inducing resin flow begins with deliberately wounding the tree, known as tapping or milking. Harvesters use a specialized small axe or chisel, sometimes called a mangaf, to make a shallow incision into the bark of a mature tree. This cut, made about one meter above the ground, pierces the outer layer to reach the resin ducts beneath.
The initial milky-white sap that oozes out is often impure and of lower quality. This first yield is generally scraped away or left to dry and is not the final product. Harvesters return to the same tree several times over weeks or months, making successive, clean cuts near the original wound. This repeated “milking” stimulates the tree to produce a cleaner, more fragrant resin in subsequent flows.
Curing, Collection, and Grading the Resin
After tapping, the liquid resin is allowed to cure on the bark for approximately ten days to two weeks. Exposure to air causes the initially milky substance to crystallize and harden into solid, tear-shaped droplets. This hardening concentrates the aromatic compounds, including terpenes and boswellic acids, giving the frankincense its characteristic scent and texture.
The hardened resin is then carefully scraped from the trunk and the ground below the tree, often collected in baskets or bags. This raw harvest is typically a mixture of resin tears, small pieces of bark, and other debris. To prepare it for sale, the resin must be meticulously cleaned and sorted by hand to remove impurities like wood fragments.
The final step is grading, where the quality of the frankincense is assessed based on several physical characteristics. The most sought-after grades are determined by color, with pale or silvery-green tears, such as the Omani Hougari Royal, fetching the highest price. Other factors influencing the grade include the size of the tears, the resin’s translucency, purity, and fragrance. Darker, smaller, or less fragrant resins are classified as lower grades and are often used for bulk applications.