If fire, grazing and insect attack, the most likely causes of decline, remain unchecked, then frankincense production could be doomed altogether.
Trees that produce frankincense, a fragrant resin used in incense and perfumes and a central part of the Christmas story, are declining so fast that production could be halved over the next 15 years, scientists said on Wednesday.
In a study published in the British Ecological Society's Journal of Applied Ecology, ecologists from the Netherlands and Ethiopia looked at large-scale field studies and predicted that tree numbers could decline by 90 percent in the next 50 years.
If fire, grazing and insect attack, the most likely causes of decline, remain unchecked, then frankincense production could be doomed altogether, they warned.
Frankincense, best known in religious teachings as one of the gifts laid before the newborn Messiah, is obtained by tapping various species of Boswellia, a small, deciduous tree that grows across Africa from northern Nigeria to the highlands of Ethiopia and Eritrea.
Cutting the Boswellia's bark produces the frankincense resin, a white substance with a strong, sweet smell. The resin is burnt in churches, mosques and at ceremonies, as well as being used by the perfume industry and in herbal medicines.
Despite its economic importance, incense has been traded internationally for thousands of years, little is known about how tapping affects Boswellia populations.