This large thorn tree is found growing in dry river beds from about Rehoboth to the Kunene River and inland as far as Windhoek and Outjo. It also occurs in the extreme eastern Zambezi region.
The Ana tree's white branchlets and broad woody pods that are curled and orange in colour make it easy to identify. It was transferred from the Acacias into its own genus Faidherbia because of its reverse annual cycle – bare in summer and in leaf and flower during winter. This characteristic is thought to be an adaptation to counteract water-logging as a result of rising water tables in the rivers after heavy rains. This feature is also the origin of the name 'wither-thorn'.
Names: G: Anabaum A: Anaboom; Her: Omue; N/D: Anahais Nd & Ky: omuyele; Lozi: mbunga. 
Many Ana trees can be seen from the bridge over the Okahandja River on the B1, where they grow in the river bed. They can also be seen on the banks of the Khan River along the B2, along the road from Brandberg to Khorixas and in the dry water courses of north-western Namibia. The Ana tree occurs very widespread throughout Africa up to Egypt and on the Arabian Peninsula.
It is a large tree, up to 20 m high, with spreading branches. The pale grey to white twigs zigzag from one pair of thorns to the next. Pale grey-green and smooth, the trunk may be fissured lengthwise or rough and dark brown on older trees. 
The finely divided, fairly large feathery leaves are grey-green and similar to those of the acacias. Cream coloured thorns with brown tips grow in pairs and are only about 2 cm long.
Numerous cream coloured flower spikes appear from March to September and are quite conspicuous because no other trees are in flower at that time.
The fruits resemble dried apple-rings (this tree's name in Zimbabwe is 'apple-ring thorn-tree'). They are bright orange to reddish brown, curled and twisted, measuring up to 25 x 5 cm. Highly nutritious and relished by game and stock, they are stored as fodder in many communities in north-western Namibia. A large tree may yield a ton of pods.
In the Kunene region the branches and strips of the bark are used for the construction of traditional huts, while hollowed trunks serve as drinking troughs. The Ana tree is one of Namibia's fastest growing trees and suitable for large gardens in frost-free areas.
Several references on the internet emphasise the soil fertility building properties of the Ana tree e.g. “From mineralisation of leaf drop and nodulation there is a marked increase in fertility from the dripring of the tree to the trunk, particularly in nitrogen, phosphorus and exchangeable calcium. Millet (Pennisetum typhoides) yields are multiplied 2,5 times and protein content by a factor of 3 or 4 near the trees.” Especially in West Africa crops are grown under these trees that provide shade in summer and allow enough sun in winter while acting as small 'fertiliser factories'. The Namibian.