Researchers propose continual cutting of stumps, application of basal bark herbicide, as well as manual uprooting as the best ways of taming the Prosopis juliflora, a kind of mesquite that has become a menace in Africa.
Experts say these methods have successfully controlled the invasive tree in Ethiopia, Kenya, and Tanzania, and even reported elimination of the herb, according to a new study led by CABI, a non-profit dealing in agricultural and environmental issues.
The research, conducted over a span of three years and published in the journal CABI Agriculture and Bioscience, demonstrated that treatments involving complete manual removal were more effective in more productive and diverse vegetation compared to the treatment that targeted standing trees (basal bark).
Widespread destruction
Prosopis juliflora is one of the world’s most threatening non-native tree species. Introduced to eastern Africa in the 1970s to provide wood and fodder and reduce erosion on degraded land, it has since spread rapidly with a severe impact including loss of grazing land, loss of access to water, declining biodiversity, reduced human health, increased human-wildlife and human-human conflicts.
For instance, Prosopis juliflora has invaded 1.2 million hectares of land in Ethiopia’s Afar region since its introduction in 1990. A previous study conducted by Shiferaw et al. revealed that this alien tree consumes an excessive amount of water throughout the year — 3.1-3.3 billion m³/year — significantly affecting both floodplains of Awash River and surrounding dryland habitats.
The CABI study also explored additional restoration interventions in Ethiopia’s Afar National Regional State, Kenya’s Baringo County, and Tanzania’s Moshi District. These interventions included divots, combined with mulching or grass seed sowing.
“The results show it is possible to restore land previously invaded by Prosopis juliflora. Despite variations in vegetation establishment rates and species composition, our interventions resulted in some cases containing a substantial fraction of perennial grasses,” said lead researcher, Dr Rene Eschen.
“The choice of method for controlling Prosopis juliflora depends on resource availability including herbicides and whether or not rootstocks need to be removed for future crop planting,” he said.
In response to the menace posed by the invasive tree species Prosopis juliflora in Africa, researchers have proposed a multi-pronged approach to tame its spread. The study, led by CABI, a non-profit organization specializing in agricultural and environmental issues, suggests three primary methods for controlling the spread of this troublesome mesquite.
The proposed methods include continual cutting of stumps, the application of basal bark herbicide, and manual uprooting. These techniques have already shown success in controlling Prosopis juliflora in Ethiopia, Kenya, and Tanzania, with some reports even indicating the complete elimination of the invasive tree.
The research, conducted over three years and published in the journal CABI Agriculture and Bioscience, compared the effectiveness of different treatments. The results showed that complete manual removal of the invasive tree was more successful in areas with more productive and diverse vegetation compared to the treatment that targeted standing trees using basal bark herbicide.
Prosopis juliflora is considered one of the world’s most threatening non-native tree species. Initially introduced to eastern Africa in the 1970s with the intention of providing wood and fodder while reducing erosion on degraded land, the tree has since spread rapidly, leading to significant negative impacts. These consequences include the loss of grazing land, restricted access to water sources, declining biodiversity, reduced human health, and increased conflicts between humans, wildlife, and other humans.
For example, in Ethiopia’s Afar region, Prosopis juliflora has invaded a staggering 1.2 million hectares of land since its introduction in 1990. A previous study indicated that this alien tree consumes an excessive amount of water throughout the year, significantly affecting the floodplains of the Awash River and surrounding dryland habitats.
The CABI study also explored additional restoration interventions in Ethiopia, Kenya, and Tanzania. These interventions included using divots, combined with mulching or grass seed sowing. The researchers found that despite variations in vegetation establishment rates and species composition, some of these interventions resulted in substantial fractions of perennial grasses, showing that it is possible to restore land previously invaded by Prosopis juliflora.
Lead researcher Dr. Rene Eschen emphasized that the choice of method for controlling Prosopis juliflora depends on the availability of resources, including herbicides, and whether or not rootstocks need to be removed for future crop planting.
In the face of this significant ecological challenge, the research provides valuable insights and potential solutions for addressing the threats posed by this invasive tree species and restoring affected landscapes in Africa.
