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Christ's Thorn Jujube (Ziziphus spina-christi) derives both its common and scientific names from the belief by many that this tree provided the crown of thorns said to have been placed on Jesus' head before he was crucified. Throughout history, but especially in the Middle Ages, the tree was seen as sacred and was used for food. Today, in parts of its range it is still heavily used for a range of purposes, including its reputed medicinal properties.
Christ's Thorn Jujube is found over the whole Sahelian region from Senegal to Sudan and across a large portion of North Africa, the Middle East, eastern Afghanistan, and northwestern India. It can generally be found up to around 600 m, but has been reported from elevations as high as 1,500 m. It can tolerate high temperatures and grows in desert areas with annual rainfall of 50 to 300 mm, but is also often found in wadis where underground water is available. In some areas, such as the Nile Valley in Egypt, the tree is cultivated in villages and parks. The fruits of Christ's Thorn Jujube are used as food especially by people in western and central Sudan and other Saharan regions, as well as in Oman. Fruits are collected by women and children and sold in local markets.
Christ's Thorn Jujube was once the dominant tree in Mediterranean savannoid vegetation in Israel, but in recent years there has been concern over the large-scale mortality in remaining stands of this species, particularly in northern Israel. A proposed explanation for the high mortality of these trees is the increased infestation by the hemiparasitic mistletoe Plicosepalus (formerly Loranthus) acaciae (Loranthaceae). In some areas, up to 80% of Christ's Thorn Jujube trees are infested by P. acaciae. The invasion of new habitats by P. acaciae throughout its distribution in Israel is believed to be the result of the increase in the population of its main seed disperser, the Yellow-vented Bulbul (Pycnonotus xanthopygos) (this species is closely associated with human settlements, which have increased in both number and size since the 1960s). The increase in bulbul populations and increased abundance and dispersion of P. acaciae is correlated with the large-scale mortality that has also been recorded in the three Acacia tree species that are the common desert hosts of P. acaciae and it is possible that these acacias and Christ's Thorn Jujube are suffering from increased mistletoe infestation facilitated by Yellow-vented Bulbul populations that are thriving as a result of their association with expanding human settlements. Christ's Thorn Jujube is very patchily distributed in Israel and often occurs in isolated clumps of just a few individuals, making its persistence sensitive to a range of negative impacts on its population.
(Dafni et al. 2005; Ward et al. 2006 and references therein; Saied et al. 2008 and references therein)