Boswellia sacra (commonly known as frankincense or olibanum-tree)<ref name=grin>Template:GRIN</ref> is a tree in the Burseraceae family. It is the primary tree in the genus Boswellia from which frankincense, a resinous dried sap, is harvested. It is native to the Arabian Peninsula (Oman, Yemen), and northeastern Africa (Somalia).<ref name=grin/>
This species of Boswellia is a small deciduous tree, which reaches a height of Template:Convert, with one or more trunks. Its bark has the texture of paper and can be removed easily. It has compound leaves and an odd number of leaflets, which grow opposite to one another along its branches. Its tiny flowers, a yellowish white, are gathered in axillary clusters composed of five petals, ten stamens and a cup with five teeth. The fruit is a capsule about Template:Convert long. The new leaves are covered with a fine down.
Individual trees growing on steep slopes tend to develop some buttressing that extends from the roots up into the base of the stem. This forms a sort of cushion that adheres to the rock and ensures a certain stability.
Occurrence and habitat
B. sacra tolerates the most critical situations and often grows on rocky slopes and ravines, up to an altitude of Template:Convert, mostly in calcareous soil. Boswellia sacra is abundant in Oman in arid woodland, on the steep, precariously eroding slopes in the mountains of Dhofar, but it is most prevalent in northern Somalia.<ref name=iucn/>
In Somalia, frankincense is harvested in the Sanaag and Bari regions: mountains lying at the northwest of Erigavo; El Afweyn District; Cal Madow mountain range, a westerly escarpment that runs parallel to the coast; Cal Miskeed, a middle segment of the frankincense-growing escarpment; Karkaar mountains or eastern escarpment, which lies at the eastern fringe of the frankinscence escarpment.<ref>Template:Cite book</ref><ref name="AP-20161225">Template:Cite news</ref>
In Dhofar, Oman, frankincense species grow North of Salalah and were traded in the ancient coastal city of Sumhuram, now Khor Rori.
The trees start producing resin when they are about 8 to 10 years old.<ref>Template:Cite web</ref>
The resin is extracted by making a small, shallow incision on the trunk or branches of the tree or by removing a portion of the crust of it. The resin is drained as a milky substance that coagulates in contact with air and is collected by hand.
Growing conditions vary significantly, affecting both tree development and resin produced. Trees in the narrow fog-laden zone where the desert meets Dhofar mountain range, a region known as the Nejd, grow extremely slowly and produce very high quality resin in large, white clumps. Not surprisingly, Omanis and other Gulf State Arabs consider this to be superior to all other resins produced in North and Northeast Africa, India, and Asia, and it is priced accordingly.Template:Citation needed
Recent studies have indicated that frankincense tree populations are declining due to overexploitation. Heavily tapped trees have been found to produce seeds that germinate at only 16% while seeds of trees that had not been tapped germinate at more than 80%.Template:Citation needed