Bringing science and development together through news and analysis

  • Saviour tree turns scourge in Kenya

[NAIROBI] A tree introduced to Kenya to combat desertification has itself become a problem, invading farmland and damaging farmers' livelihoods.

Prosopis juliflora, known as the 'devil tree' in some areas, was introduced from Latin America to semi-arid districts of Kenya by nongovernmental organisations in the 1980s.

It was selected because of its ability to survive in dry environments and for its expansive root system, which helps bind soil and prevent erosion.  

Now P. juliflora is the target of a planned government control programme after research by Gabriel Muturi of the Kenya Forestry Research Institute (KEFRI), published in April, found that up to 27 million hectares of land are at risk from the plant.

The study, carried out in Turkana district in northwest Kenya, also showed that a local species of acacia tree, Acacia tortilis, is declining by over 40 per cent in some areas possibly because P. juliflora is displacing it.

Farmers in the Baringo district of Kenya's Rift Valley province have sued the government for millions of Kenyan shillings for loss of grazing fields and arable land caused by the alien tree's invasion.

The farmers say they have lost animals, which died because they were unable to eat when their teeth fell out after feeding on the shrub.

"The government is working round the clock to come up with a policy on management of the species," said Raphael Mworia, spokesperson for the Kenya Forestry Service (KFS).

"A policy paper detailing where it can be planted, when and in what numbers is being worked on and soon the government will be able to release the guidelines to the public," added Mworia.

Meanwhile the KFS is training farmers on how to live with the shrub, by using its pods for fodder and stems for firewood timber and charcoal.

"Pastoralists must now start making use of the benefits that come with the species instead of looking at the negative aspects of it all the time," said Mworia.

Mworia added that increased use of P. juliflora for charcoal would save the over-exploited acacia species from being used for this purpose.