Frankincense can be harvested more gently in the future

New findings on the course of the lines in the trunk facilitate the resin extraction

Frankincense is the dried resin of the tree Boswellia papyrifera. © public domain
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Frankincense was already a precious gift in antiquity - that is why the three wise men from the East should also have given this spicy-smelling resin to the newborn Jesus. But even today frankincense is a real economic factor. An international research team has now found out how the resin can be harvested more gently for the tree in the future. For the first time, botanists analyzed the complex pipe system with which the tree distributes its resin in the bark.

Frankincense is produced by trees of the species Boswellia. It is obtained by scratching the bark of these trees and collecting the dripping resin. This so-called tapping is typically carried out simultaneously at several points of the strain. A single tree can deliver 200 to 350 grams of the strongly smelling substance per year. The main exporter of frankincense is Ethiopia, which produces around 4, 000 tons of frankincense each year on the world market. However, the high demand for the resin could jeopardize the survival of the Boswellia trees in the long term, the Dutch-Ethiopian research team now warns.

Constant injury makes trees more vulnerable

"In some areas, the great demand for frankincense has already led to over-exploitation of the trees, " explains Motuma Tolera of Wageningen University in the Netherlands. Normally, tapping is repeated about 8 to 12 times per tree during the dry season - and rising. The constant scarring but create wounds in the trunk and make the trees so vulnerable to insect pests. The more wounds, the more susceptible the tree will be. Some trees even died as a result. "This is bad for the trees, but also for the people in these regions, who live on the incense harvest, " says the botanist.

One of the problems with the previous harvesting methods is the lack of knowledge about the exact architecture of the resin lines, the researchers explain. Therefore, this line system has now been examined more closely. "What we found is a three-dimensional network of interconnected channels in the inner bark, " says Tolera. Most of these lines would be within a mere seven millimeters thick bark zone. This care for the transport of the resin in the tree. Some additional channels also connect this braid to the interior of the trunk.

Leaf and leaves of the frankincense tree Boswellia sacra. Historical drawing from K hler's medicinal plants (1897)

These new findings could make the resin harvest more effective in the future and more gentle on the tree, the researchers say. Because so far you start with a shallow incision, which is then successively torn up again and again and gradually deepened. As a result, almost always a wound on the tree. Most incense usually flows only after five to seven rounds of tapping. "A cut that goes deeper at the beginning could allow the resin to flow much more effectively, " says Tolera. This also reduces the number of cuts and thus the damage to the trees. The incense harvest could thus be richer and gentler. (Annals of Botany, doi: 10.1093 / aob / mcs236) Display

(Oxford University Press (OUP), 21.12.2012 - NPO)