This archive report was first published on 17 July 2020.
Acacia Tortilis: A Versatile Tree Species ¶
Published on July 17, 2020
Acacia tortilis is a common tree species found in most of dry Africa, from North and West to the South of the continent. In Kenya, it is widespread in lowland arid and semi-arid regions, thriving in areas with an altitude range of 0 to 1,650 metres above sea level and annual rains of 150-900mm.
The tree has numerous uses, including firewood, timber, charcoal, poles, edible pods, medicine, fodder (pods and leaves), bee forage, shade, dune fixation, nitrogen fixation, soil conservation, fibre (from bark), live fence, and dye. Its thorns are used as pins or needles.
One of the significant benefits of Acacia tortilis is its nutritious fodder, which makes it an excellent source of food for herbivores. The leaves and pods are collected and saved for the dry season and even sold in northern Kenya. A 10-year-old tree yields up to six kilos dry leaf and 12kg of pods per year.
The foliage is a favourite for sheep, goats, camels, cows, and wildlife. The leaves are fed green as well as dry, with a crude protein content of up to 18 per cent and digestibility of 46.2 per cent. The pods also have high levels of carbohydrates, minerals, and crude fibre.
Acacia tortilis plays a crucial role in nitrogen fixing, making it a soil improver. It is also used in erosion control, as it grows quickly and stabilises shifting sand dunes or hill slopes. In India, it is used to make shelterbelts along highways, railways, and farms.
The tree's dense, red hard wood has high calorific value, making it superior firewood and charcoal. The tree starts giving fuel wood at the age of eight to 10 at the rate of 50kg/tree. Twigs, branches, and thorns are used as fencing materials, while bigger branches are used as poles for erecting fences around farms and plantations.
Acacia tortilis is a sustainable source of fuel wood, as it is fast-growing and multiple-stemmed. The tree's gum is used to treat ocular infections, jaundice, and pulmonary diseases in Egypt, Libya, Tunisia, Algeria, and Morocco. The dried powdered bark is used as a disinfectant in healing wounds, and the seeds are taken as an anti-diarrhoeic.
Propagation of Acacia tortilis is by seedlings, wildings, and direct sowing. However, seedlings are the most popular method. Seeds cost Sh2,500 a kilo at Kefri shops. It is essential to keep animals, especially goats, away from the tree due to its nutritious leaves. Seeds of Acacia tortilis have a hard coat that is impervious to water, causing seed dormancy and extended germination time.
