Acacia senegal Gum arabic tree

Origin

Sahel, Africa.

Ecology

Annual rainfall: 100-800mm.

Normal temperature range: 14-43°C.

Altitude range: 100-1700m.

Seasonal adaptability: dry season of 8-11 months.

Soils: grows on sandy soils and also clay if no waterlogging. Optimum pH 5-8.

Light requirement: strong demander.

Description

Height at maturity: 2-13m.

Form: poor, short bole and spreading crown

Coppicing ability: good

Growth: 0.3m in height and 1.4cm in diameter per year.

Other: small, thorny, branchy tree with light grey to light brown scaly bark. Thorns black 3-7mm long, in triplets and claw like. Flower clusters cylindrical, 2-10 cm long, at leaf nodes. leaves bipinnate 2-6 cm long, shorter than flower clusters.

Primary advantages

Highly drought resistant, easy to propagate.

Primary disadvantages

Susceptible to grazing damage in early years. Can spread rapidly in fallow areas, becoming a weed.

Products and yields

Wood products: good quality fuelwood. Poles and agricultural tools. Timber yields are about 5m³/ha/yr from natural forest. Where gum is harvested wood yields drop to about 1m³ or less in plantations.

Fuelwood: 3200kcal/kg

Fodder: leaves and pods have high protien content. Seeds are also eaten by humans.

Other: the major source of gum arabic. Root fibres are used to make ropes and fish nets. Bee fodder. Suitable for erosion control and soil improvement, especially in desert conditions.

Propagation

Seed, either in plastic pots or by direct seeding.

Seed treatment

Pretreatment: soak in concentrated sulphuric acid for 20-30 minutes or soak in cold water for 48 hours.

Management

Needs protection from grazing, weeds and fire for 2 years.

Agroforestry uses

Intercropping, at wide spacing (10x10m), live fences and pastoral systems when established.