Boswellia sacra

From www.plantsasmedicine.com

Boswellia sacra

Countries in which Boswellia sacra is native

Boswellia sacra Flueckinger (synonym Boswellia carterii Boswellia thurifera) is a bush or tree in the Burseraceae family,^[1] the same family as Commiphora myrrha, the true myrrh tree. Boswellia sacra is the tree from which true frankincense is harvested. Its status is Near Threatened (IUCN 2.3). The tree is native to "lower elevations of northern Somalia, southwestern Oman, [and] southern Yemen."^[2] It grows to a height of up to 7.5 m (25 ft.).^[2]

It is found in altitudes of about 730–1230 m.^[3]

The plant produces flowers and fruit (photo: [1]) from September to November in the Northern Hemisphere.^[3]

Frankincense Production

Frankincense from "Boswellia sacra" in Oman

Frankincense is a hard, resinous substance, which may be opaque, white or yellowish crystalline. Frankincense has its own characteristically pleasant, pine foresty, aromatic scent. With respect to solvents, there are three parts to frankincense. The gum fraction dissolves in water, the oleo fraction dissolves in oil, and the resin fraction dissolves in alcohol.

Frankincense can be harvested when the tree is 5–7 years old. The tree should be about 4–5 m tall and have a trunk diameter of about 15 cm, when measured 1.3 m above the ground.^[3]

The tree has papery bark, which peels into thin, tan sheets. Cracks or wounds in the tree trunk emit a white sap, which evaporates to form frankincense.

Commercial production of frankincense entails making a horizontal incision into the tree and peeling a patch of bark off of it. This causes larger than normal amounts of frankincense to form. In order to preserve the health of the trees, one would make the fewest number of incisions necessary, in order to let the trees thrive and to reproduce, making the harvesting of frankincense renewable.

Trees produce an average of about 2–3 kg of frankincense per year.^[3]

Essential Oil

Frankincense from Boswellia sacra produces about 3^[4]–5.5^[5]% essential oil via steam distillation.

Compound	% of total	Scent
Limonene	33.5%	Smells like oranges
E-β-ocimene	32.3%	Smells like pine and citrus
Myrcene	6.9%	Smells like hops
α-Thujene	6.6%	"Smells like grass and soy sauce"^[6]
Sabinene	5.2%
α-pinene	5.3%	Smells like pine
β-pinene	1.8%	Smells like pine

The diterpenoid (C20) compounds with the largest presence are isoincensole and isoincensole acetate.^[7] This means that incensole acetate can be had not only from Boswellia sacra frankincense, but also from the frankincense essential oil. Incensole acetate has been shown to have antidepressant and antianxiety properties.

Sustainability

Boswellia sacra

Almost all trees from which frankincense is harvested are wild trees, so sustainability in the harvest of frankincense is an issue. Carbohydrates that the tree normally uses in its reproductive cycle, that is, production of flowers, seeds and fruit, are diverted toward the production of frankincense. It is conceivable that over-harvesting of frankincense could lead to a decrease in the population of frankincense trees over time. Rule of thumb has it that harvesters should let a tree rest for a year after the third year of frankincense harvesting.

Cultivation

A Boswellia sacra tree being cultivated inside of Biosphere II in Arizona, U.S.A.

USDA Zones: 10–12^[2]

Boswellia sacra can be propagated from seeds or from cuttings, but the seeds have a relatively low rate of germination.^[2] Cuttings taken from the roots can also be used to propagate it.^[8]

In nature, it is found in areas with rainfall of 100–500 mm (about 4–20 in.) per year.^[3] It is found at altitudes of less than or equal to about 1230 m (4035 ft.).^[3]

In Arabia and Africa, seeds from the tree fall into cracks in the surrounding limestone. Water from rain fills the cracks and seeds germinate. The trees form special bonds with limestone cliffs and can be found there.

In order to get a close a match to the soil in which Boswellia sacra evolved, home cultivators need alkaline soil, since limestone is alkaline. The recommended pH range can be found with Google Search.