By HENRY OWINO (Senior Correspondent)

A new research study by a team of scientists says  that human activities can change the structure and function of the environment with cascading impacts on human health, a concept known as ‘Planetary Health’.

According to the authors of the new study, published in the journal, One Earth, planting trees and management is involved in many of these chain reactions.

The research team set out to understand does agroforestry the integrated management of trees, crops and livestock alter microclimates, hydrology, biogeochemistry and biodiversity for the betterment or detriment of human health in Sub-Saharan Africa? 

Apart from the nutritional benefits of increased fruit consumption from trees in orchards, homegardens and mixed species’ farm-plots, the ways agroforestry affects human health are little discussed. 

To reach a better understanding, the team of 21 researchers, two from the London School of Hygiene and Tropical Medicine and the rest from World Agroforestry (ICRAF) based at research centres throughout the Sub-Saharan Africa region. Analyzed the ways agroforestry affects food and nutrition security, the spread of infectious disease, the prevalence of non-communicable diseases, and human migration. 

“The diversity of ways that agroforestry influences human health by changing the environment was perhaps the most surprising result,” said Todd Rosenstock, leader of the research team.

“I imagined there would be evidence suggesting that consuming fruit helps with diet-related health concerns. But we also found work highlighting the benefits of trees for reducing dust and increasing shade; but also increasing the abundance of mosquitoes.” He compared.

Despite some increased risks of infectious disease, overall, they found that increased use of agroforestry could improve a diverse range of pressing health concerns. The authors argue that outcomes are very much linked to specific contexts, with the effects on human health determined by ecology, tree species and tree management. 

“Agroforestry includes a wide variety of techniques to manage trees, crops and livestock together, creating lots of options for farmers, ranchers and communities to select the right trees for the right places and their objective,” remarked Roeland Kindt, co-author and senior ecologist with ICRAF.

However, the tremendous number of agroforestry options has led to mixed results when examining why agroforestry is not more widespread, notwithstanding the benefits. Reasons found in previous studies range from insecure tenure through conflict over ownership to lack of appropriate seeds and seedlings.

When asked how agroforestry can be further expanded in scale despite the many obstacles, co-author Kai Mausch replied: “It is already happening. Countries across Sub-Saharan Africa are making plans and implementing programs to use trees to mitigate and adapt to climate change, reverse land degradation and meet energy needs.

We made great progress in the understanding of the scaling process of relatively simple agricultural technologies like seeds but also of complex systems like Agroforestry. However, they remain more difficult to scale and the evidence is not fully consistent.”

That outlook suggests trees indeed should become more widespread, which would affect Sub-Saharan African lives and landscapes. While this is a promising future, the authors caution that using agroforestry to improve planetary health will require a transdisciplinary and multisectoral effort to turn knowledge into practical and policy action.