A future for frankincense

At this time of year it is hard to escape the Three Wise Men, rid­ing their camels across Christmas cards and appear­ing in mini­ature form in count­less school nativ­ity plays across the world, bear­ing their gifts for the infant Jesus. Whilst we are all famil­iar with gold (espe­cially in this Olympic year), it is the men­tion of frankin­cense and myrrh that really says “Christmas” to us and takes our ima­gin­a­tions back to ancient times. But you might be sur­prised to learn that these two fra­grances are still big busi­ness today; for example, Ethiopia alone trades around 4000 tonnes of frankin­cense every year. This is all the more remark­able because a single tree from which the resin is har­ves­ted will typ­ic­ally yield about 200–350g per year. The main inter­na­tional trade comes from a tree called Boswellia papyrifera, and Ethiopia is the main export­ing country.

Boswellia Trees

Boswellia Trees in Ethiopia. Photo by Motuma Tolera.

Frankincense is har­ves­ted by wound­ing the bark of trees and col­lect­ing the resin that is sub­sequently released from the wound, a pro­cess known as tap­ping. Tapping is car­ried out at sev­eral spots along the stem, using a tra­di­tional type of tool that resembles a chisel. The pro­ced­ure is repeated in 8–12 tap­ping rounds dur­ing the dry sea­son, which lasts about 8 months. But high demand means that many trees are being over-exploited and pop­u­la­tions are at risk of dying out, threat­en­ing the live­li­hoods of vil­la­gers who depend on them. But help may be on hand as the res­ults of a new study by bot­an­ists from Ethiopia and the Netherlands led by Motuma Tolera, which could secure a future for the trees by reveal­ing the ana­tomy of the resin secret­ory sys­tem.

Motuma Tolera explained: “In some areas, the high demand for frankin­cense is caus­ing over-tapping, which is bad for a couple of reas­ons. Tapping the tree cre­ates wounds in the stem that take resources to be healed, and more wounds cre­ate more oppor­tun­it­ies for insects to attack the tree. It’s not a sur­prise that some trees die. This is bad for the tree but also for the people liv­ing in those areas, since they depend on the resin pro­duc­tion, both eco­nom­ic­ally and culturally.

One of the prob­lems is the lack of know­ledge of the type, archi­tec­ture and dis­tri­bu­tion of resin pro­du­cing, stor­ing and trans­port­ing struc­tures in the tree. Such know­ledge is needed for improved tap­ping tech­niques in the future.”

Tapping a tree for Frankincense resin.

Tapping a tree for Frankincense resin. Photo by Motuma Tolera

The study, pub­lished this month in the Annals of Botany provides this detailed know­ledge for the first time. It is avail­able with free access.

Motuma Tolera said: “What we found was a 3-D net­work of inter-connected canals in the inner bark. Most of these canals are within a very nar­row region of the inner bark, in a zone that is less than 7 mil­li­meters thick. These allow for the trans­port of resin around the tree. We also found a few canals con­nect­ing deep into the xylem, the heart of the tree.”

The find­ings will have prac­tical applic­a­tions for the people of Ethiopia and other frankin­cense pro­du­cers. Traditional tap­ping starts with a shal­low wound, from which a rel­at­ively small amount of resin is released. The wound is then re-opened later with a cut that goes a bit deeper and more resin is col­lec­ted – a pro­cess that is repeated over and over again. The amount of resin col­lec­ted peaks after about 5–7 rounds of tap­ping, which the study sug­gests is the point at which the wound reaches the main region of resin canals.

Motuma Tolera said: “Our res­ults sug­gest that tap­ping can become more effi­cient. A cut that goes deeper, earlier in the tap­ping cycle, may drain the resin more effect­ively. Since the 3-D resin canal net­work may allow for long dis­tance move­ment of resin when it is intact, this would be an option to reduce the num­ber of cuts, and reduce the dam­age to the trees. New stud­ies will be needed to show how such improve­ments may keep trees healthy but still pro­duct­ive for resin pro­duc­tion. This opens new ways for a more sus­tain­able frankin­cense pro­duc­tion system.”

Resin from a tapped tree

Resin from a tapped tree. Photo by Motuma Tolera.

It’s nice to dis­cover some­thing new, but here we also have the oppor­tun­ity to give some­thing back to the people who helped us with the study. I hope every­one in Lemlem Terara, but also else­where in Ethiopia, will bene­fit from what we have found in the future.”

The team hope the res­ults mean more Boswellia trees will live to see next Christmas.

Alun Salt. ORCID 0000-0002-1261-4283

When he's not the web developer for AoB Blog, Alun Salt researches something that could be mistaken for the archaeology of science. His current research is about whether there's such a thing as scientific heritage and if there is how would you recognise it?

2 Responses

  1. Mary says:

    Great story, thanks!