Research

Australian acacias are the ideal multi-purpose agroforestry tree for arid and semi-arid regions, as they are fast growing, can increase crop yields by increasing soil fertility and fixing nitrogen in the soil, reduce erosion and provide wind-breaks and mulch for crops, increase farm income by producing timber and firewood, and in the dry season, provide fodder for sheep and cattle and pollen to produce honey.

The trees provide shade and habitat for beneficial animal species and attract insects and birds. In addition, acacia seeds have been a source of storable, nutritious food for Australian aboriginal people over thousands of years.

Getting Started

• Select an acacia species. Over 50 species of desert Australian Acacia have been identified as beneficial agroforestry trees. To date, the most valuable and well proven in the Sahel region are A. colei and A. torulosa. See ‘Acacia Species’ below.
• Select a plantation method. Acacia trees can be planted as a crop or as part of an agroforestry farming system, which is called ‘Acacia Agroforestry’.  This involves planting acacia around the boundaries of traditional food crops and inside crop borders. Acacia Agroforestry that includes Farmer Managed Natural Regeneration (FMNR), which regenerates indigenous trees, results in better windbreaks and soil improvement plus increased wood production. See ‘Factsheet: How to do Acacia Agroforestry’ for more information. Alternatively, acacia can be planted on wastelands where farming is not practiced. Nearby acacia plantations can be useful to reduce the distances required for collecting wood and fodder for animals.
• Start a village or individual nursery to grow seedlings. Australian acacia trees are most successfully introduced by planting seedlings that have been grown in village or individual tree nurseries.  See ‘Propagation’ below.
• Plant and manage the trees. Planting methods and spacing are important to optimise tree growth. Prune acacia trees every second year. See ‘Planting and Management’ below.

Acacia Species

Many of the 1,000 Australian acacia tree species evolved in a desert climate and are well adapted to dry conditions with as little as 300 mm annual rainfall and grow well in a range of soil types, especially poor sandy soils.

A.colei and A.torulosa are both valuable species that have undergone an extensive selection and trial process in Niger. These species are easily raised and established, recover rapidly after pruning and produce good quantities of wood. Side branches of both species can be pruned to produce building poles.

A.colei is the most valued and widely used acacia species in Niger, producing between 1-10 kilograms of seed in its second year.

A. torulosa has also been developed to compliment and improve on A. colei. This species is longer lived, creates less competition for food crops and produces larger seeds that are more easily harvested.

In Ethiopia, A Saligna is commonplace and provides benefits to farmer families, particularly in wood production and fodder collection.