What you need to know:
- Scientists different disciplinary backgrounds, suggests replacing the trees with grassland restoration for soil carbon accumulation.
- Mathenge was promoted by the government to provide wind breaks, timber and charcoal.
Clearing of Prosopis juliflora, commonly known as mathenge, in Baringo County, may yield bigger livelihood benefits than the current economic benefit of burning the wood for charcoal, according to scientists.
The scientists, in a new study on the weed which has been devastating many arid and semiarid lands (Asal) in Kenya since being introduced there as wind breakers, say having the trees cleared will restore the grasslands and contribute to climate change mitigation.
The team, comprising scientists from four countries and different disciplinary backgrounds, suggests replacing the trees with grassland restoration for soil carbon accumulation.
The scientists studied the impacts of mathenge invasion and grassland degradation on soil organic carbon in nine sub-locations in Baringo, where it was introduced in the 1980s. Mathenge was promoted by the government to provide wind breaks, timber and charcoal.
The scientists found that clearing the invasive weed and restoring degraded grassland in the affected ASAL areas may result in increased soil organic carbon in the long term.
A higher soil organic carbon promotes soil structure and greater physical stability by improving soil aeration (oxygen in the soil) and water drainage and retention, and reduces the risk of erosion and nutrient leaching.
Due to the fast growth and prolific seeding of mathenge, the species has become invasive across the Asal counties.
The researchers argue that there are financial as well as immaterial benefits of restoring grasslands that may re-establish within 30 years if they are not overgrazed. They say that part of the benefits could, in fact, be realised within less than 10 years.
“Climate change, land degradation, and invasive alien species such as mathenge are major threats to people's livelihoods in Asal areas with each of these having negative impacts on ecosystem services - including vegetation biomass, which is a prime resource for pastoralists and agro-pastoralists,” said the scientists in a paper published in the Journal of Applied Ecology
A Centre for Agriculture and Bioscience International ecologist, and lead author of the paper, Dr René Eschen, said: “While Prosopis does provide these benefits, it has also spread rapidly across a large area, leading to a loss of native vegetation, agricultural areas and grazing land.
These changes are primarily driven by Prosopis invasion, along with human activities .”
“Although Prosopis management is expensive, the results suggest that a large part of the costs in Baringo can be offset by immediate financial benefits from the sale of charcoal.