Classification of the genus Acacia (in the wider sense) has been subject to considerable debate. It is generally agreed that there are valid reasons for breaking it up into several distinct genera, but there has been disagreement over the way this should be done. As of 2017, it is widely (but not completely) accepted that the section that includes the majority of the Australian species should retain the name Acacia, whilst other sections of the genus should be transferred to other genera. This species is transferred to Vachellia[
Acacia songwensis Harms
Acacia xanthophloea Benth.
Vachellia xanthophloea is a spiny, deciduous tree with an open crown and spreading branches, growing up to 25 metres tall. The straight bole can be up to 60cm in diameter. The long straight white thorns are arranged in pairs and although they are very significant on young trees they often become barely noticeable on mature specimens[
The plant is harvested from the wild for local use as a food, medicine and source of wood. It is sometimes grown in hedges and is popular in gardens as an ornamental.[
Especially in times of drought, many Acacia species can concentrate high levels of the toxin Hydrogen cyanide in their foliage, making them dangerous for herbivores to eat.
East tropical Africa - Somalia, Kenya, Tanzania, Malawi, Mozambique, Zimbabwe, northern S. Africa.
Swampy localities and riverine forest, often on flood plains or in depressions, at elevations up to 2,100 metres[
]. It often grows on alluvial black clay soils[
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Older trees can tolerate moderate frosts[
The plant often grows on alluvial, black, clay soils in the wild[
]. It prefers sandy soils[
The growth rate of seedlings is fast, with plants growing up to a maximum of 7 metres tall in 3 years. A growth rate of 1.5 metres per year, and 2cm in diameter, are common in young trees[
When harvested for medicinal purposes, the bark is removed with a knife and bark collectors usually focus on larger-sized trees. The tolerance of the tree to damage is high, and usually trees recover from bark removal as well as from elephant damage. However, excessive destructive harvesting is locally common[
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[
A gum occurs in large quantities on the trunk. It is said to be edible, and is eaten by monkeys[
]. The gum is water soluble and contains galactose, arabinose, rhamnose, glucuronic acid and 4-O-methyl-α- D-glucuronic acid.[
A decoction of the bark is used to treat indigestion and sickle cell anaemia[
The powdered bark is used as an emetic to treat malaria, and also against eye complaints[
In trials, bark extracts have shown weak in-vitro antimalarial activity and considerable antimicrobial activity[
Leaf extracts have shown antibacterial activity against Staphylococcus aureus and Escherichia coli[
A popular garden tree, it has been grown in hedges[
The dappled shade produced underneath the open canopy is ideal for smaller plants which require protection from the full brunt of the suns rays but still require sufficient light[
The bark contains tannin in considerable quantity, but it does not produce good leather[
The heartwood is pale brown with a reddish tinge; it is distinctly demarcated from the wide layer of paler-coloured sapwood. The wood is moderately hard, fairly heavy; it should be dried with care because it is prone to splitting and cracking; it finishes smoothly; but is susceptible to borer attack[
]. A general-purpose timber, which is used in construction and for carpentry, boat building, boxwood, furniture, mortars, domestic utensils, troughs and fence poles[
The wood is used as firewood, although the gum leaves a black tar-like deposit when burnt. It makes good quality charcoal[
Seed - it has a hard seedcoat and may benefit from scarification before sowing to speed up germination. This can usually be done by pouring a small amount of nearly boiling water on the seeds (being careful not to cook them!) and then soaking them for 12 - 24 hours in warm water. By this time they should have imbibed moisture and swollen - if they have not, then carefully make a nick in the seedcoat (being careful not to damage the embryo) and soak for a further 12 hours before sowing. Germination of treated seed is generally fair, reaching about 70% after 2 weeks[
]. When seedlings have reached the 2-leaf stage, 6 - 8 weeks after sowing, they should be transplanted from seedling trays into nursery bags. Care should be taken not to damage the long taproot[
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