Known as Christ's thorn in English, the fruits of this tree were part of the trans-saharian caravan trade, just a century ago. This exportation from sub-Saharan Africa to Egypt was an old tradition: archeological documents of tax revenues indicate that Nubia payed part of her charges to the Pharaoh in the form of bread made from Ziziphus spina-christi. Tragically, this tree is retreating more and more, both in geographical distribution and in availability of the fruits on the market. This is in part probably caused by its characteristic of being very good firewood.
The fruits are sweet, slightly bitter and have a little bit of a nutty taste. They have a high energy density, with a carbohydrate level of 64 to 86 %. Once dried, they are easily stored, making them a suitable food for among others travel. The pulp can be used to make biscuits and the seed, which contains 30 % proteins, can be grilled and consumed like many other nuts. The flowers are an important source of nectar for bees and the honey derived from this nectar, the Sidr honey from Yemen, is one of the most expensive on the planet. According to a Sudanian study, each tree is able to produce 3,6kg of honey per year. Complementary to this, a study in Ethiopia showed this tree to be able to produce 50 to 200kg of fruit. These fruits generally ripen during the cold season, between December and January.
The tree is able to adapt to a diversity of soils in the rainfall band of 300mm and above and grows throughout all of the Sahel, in North Africa and in the Middle East. Old trees often have a hollow trunk, important for the habitation of certain insects and animals. This includes snakes, which are not very popular among villagers. At the same time, the thorns of the kurna trees are known to be used in North Africa as a remoftenedy for snake bites.
