Acacia erioloba, known as Giraffe Thorn or as Camel Thorn (a mistranslation from the Afrikaans name “Kameeldoring”, meaning Giraffe Thorn) is an African species in the large and taxonomically controversial Acacia genus. It is the dominant tree, highly recognizable, on the Kalahari plains in Angola, Botswana, Mozambique, Namibia, South Africa, Zambia, and Zimbabwe, often growing in and along the banks of riverbeds.
Camel Thorn trees grow up to 18 m tall, with a large spreading canopy that produces shade and animal shelter. Trees older than 10 years produce numerous yellow ball-shaped inflorescences, and trees older than 20 years produce crops of up to 1,200 flat, crescent-shaped seedpods per tree. Studies suggest that trees may live 250-300 years. Large herbivores, including black rhinos, elephants, giraffes, gemsbok, elands and kudus are agents of seed dispersal as they eat large numbers of pods, passing the seeds with their tough seed coats through their gut intact and then providing excellent germination conditions in the dung they expel with the seed. The trunk of A. erioloba, like many Acacia species, is covered with paired thorns about 2-5 cm long. The base of older thorns frequently houses ant galls up to 2 cm across used as protection by a large invertebrate fauna. The tap root can grow up to 60 m, allowing this tree to access deep ground water sources.
Acacia erioloba is considered a keystone species, with many other species and ecosystem parameters dependent on it. At the same time, this tree provides valuable resources to people: dark, hard, insect-resistant wood for lumber, also considered excellent for fuel and cooking purposes; abundant, nutritious pods sometimes used to make a hot coffee-like drink or porridge, and as highly nutritional fodder for cattle (although leaves and pods produce prussic acid in quantities that poison livestock at some times of the year); edible and medicinal gum and bark. Although it is a hardy species, frost and drought resistant, A. erioloba is slow-growing, slow to propagate and of most value as a large established tree. The large trees, however, are vulnerable; they are regularly cleared for agricultural and grazing development as well as harvested for lumber and for what is considered high quality charcoal and firewood. This species has protected status in South Africa.
(Arid Zone Trees 2003-2013; Orwa et al. 2009; Seymore and Milton 2003)
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