Speakers during the KISHADE Forum during a panel discussion at the 12th Tanzania Health Summit. Dr Otilia Gowelle, Director of Preventive Services Ministry of Health(right), Dr Faraja Chiwanga, Project Lead(middle) and Henry Mubi, smallholder farmer(left)
By Alfred Zacharia
A new study has provided early scientific evidence that trees in croplands can protect farmers from extreme heat, offering a natural solution to the growing health risks posed by climate change.
The study, known as the Kisiki Hai Sustainable Heat Adaptation Development (KISHADE) project, is the first of its kind in Tanzania to produce evidence showing that trees offer more than environmental benefits—they also safeguard human health.
Led by the LEAD Foundation, the project brings together global and local institutions including the London School of Hygiene and Tropical Medicine, the University of Dar es Salaam, the University of Dodoma, Muhimbili National Hospital and Meta Meta, with funding support from the Wellcome Trust.
A new solution to an old problem
Farmers in the Kisiki Hai programme—which has restored more than 30 million trees across 260,000 households—have long claimed that trees cool the environment and ease their work in the fields. But until now, those claims remained largely anecdotal.
“Our focus is on finding out if growing crops alongside trees can make a difference in farmers’ health by changing the local environment around them,” said Dr. Faraja Chiwanga, an internal medicine specialist and Director of Curative Services at Muhimbili National Hospital, who serves as the project lead.
The research findings were shared at the 12th Tanzania Health Summit, held in Dar es Salaam, during a special forum dedicated to heat adaptation in agriculture.
According to Dr. Chiwanga, the health threats facing agricultural workers are escalating as Tanzania experiences longer, hotter seasons.
“Outdoor agricultural workers face rising risks of heat-related illnesses, including dehydration, chronic kidney disease and cardiovascular strain,” she explained. “These risks are compounded by the lack of shade and cooling infrastructure in most farms, making heat stress a barrier to health and productivity.”
Gathering scientific evidence
To put farmers’ experiences to the test, researchers under the KISHADE project used wearable sensors to monitor body temperature and heart rate in real time.
They also collected urine and blood samples to detect potential health problems linked to excessive heat exposure.
At the same time, advanced sensors measured local climate conditions, enabling the team to compare differences between farms that practice agroforestry and those that do not.
Preliminary results are already pointing to a measurable difference.
“Our early analysis from Bahi District shows that farms using the Kisiki Hai method recorded significantly lower outdoor temperatures and a reduced heat index compared to non-implementing farms,” said Dr. Peninah Murage, an Assistant Professor of Environmental Epidemiology at the London School of Hygiene and Tropical Medicine.
He added; “Further analysis will tell us whether these differences translate into better health outcomes for farmers.”
Dr. Richard Sambaiga, Head of Sociology and Anthropology at the University of Dar es Salaam and a co-investigator, noted that community involvement has been key to the study’s success.
“Farmers have responded positively to using wearable technology that tracks their health outcomes, showing strong engagement and willingness to participate,” he said.
He added that support from community leaders and an advisory board has smoothed the recruitment process and data collection.
“The community engagement and successful sensitization at all levels are truly inspiring and are driving our progress,” he said.
Building knowledge and resilience
The KISHADE project is not just about collecting data—it is also strengthening Tanzania’s scientific capacity. By training young researchers and providing practical skills, the project is building local expertise that will continue long after the study ends.
“The legacy of this work will extend far beyond the project itself,” said Dr. Sambaiga. “We are creating a foundation of knowledge and skills that will help the country adapt to the challenges of a warming climate.”
Wider implications
Experts say the findings have significance far beyond Tanzania’s borders. Dr. Ivan Ivanov, an occupational health specialist from the World Health Organization (WHO), stressed that working in hotter environments is becoming increasingly dangerous worldwide.
“Governments must prioritize the health, safety and well-being of workers in climate adaptation plans,” he said. “Employers should implement worksite heat action plans to ensure safe and resilient workplaces.”
He added that sectors ranging from agriculture to construction and large public events are already at risk from heat-related illnesses, which are compounded by rising global temperatures, air pollution and UV exposure.
The Tanzania Meteorological Authority (TMA) also welcomed the study, noting that localized climate data will be vital in shaping national policies. “This research is helping us understand how microclimates created by trees can mitigate the impacts of climate change,” a TMA representative said.
From farms to policy
With over 70 percent of Tanzania’s workforce engaged in agriculture, the stakes are high. If proven effective, tree-based farming could offer policymakers, health workers and farmers an affordable and scalable tool to reduce heat-related risks.
“This research shows the power of applying scientific rigor to community-based solutions,” said Dr. Chiwanga. “Planting and preserving trees is not only good for the environment—it directly safeguards health and supports livelihoods in a warming world.”
Beyond farmers, the study’s findings are expected to inform guidelines for government authorities, NGOs and international organizations working on climate adaptation. Donors will also be able to assess the return on investment in nature-based solutions.
A glimmer of hope
As the world continues to grapple with climate change, the KISHADE project offers hope that simple, natural solutions can make a measurable difference.
The project’s data on microclimate and health will be a significant contribution to the growing field of planetary health, with lessons that could benefit vulnerable populations globally.
“Ultimately, this is about resilience,” said Dr. Murage. “If trees can cool the land and protect farmers from heat stress, then we have a powerful, low-cost solution that works with nature rather than against it.”
For Tanzania’s farmers who spend long hours under the sun, producing the food that feeds the nation, the shade of a tree may prove to be more than comfort. It could be a lifeline.