Study: Tree-planting could cut heat risks for millions of Tanzanian farmers

The study was conducted in four Dodoma Region districts: Chamwino, Bahi, Kongwa, and Mpwapwa, aimed to evaluate heat adaptation interventions to help manage heat's health effects.

The research is a collaboration with the London School of Hygiene and Tropical Medicine, the University of Dar es Salaam, the University of Dodoma, Muhimbili National Hospital, and MetaMeta.

The findings, presented on Friday, October 3, 2025, at the sideline meeting of the 12th Tanzania Health Summit, were made possible through the LEAD Foundation.

An internal medicine specialist and Director of Curative Services at Muhimbili National Hospital, Dr Faraja Chiwanga, who leads the project under LEAD, said the aim is to determine whether agroforestry can improve farmers’ health by transforming their immediate environment.

“For years, farmers engaged in the Kisiki Hai (Live Stump) programme, which has restored more than 30 million trees across 260,000 households, have reported that trees offer natural cooling. The KISHADE project is scientifically testing that claim,” she said.

Dr Chiwanga noted that the project, the first of its kind in Tanzania, is funded by the Wellcome Trust and seeks to provide concrete data rather than anecdotal evidence on the health benefits of agroforestry.

With over 70 percent of Tanzania’s workforce engaged in agriculture and exposed to extreme outdoor conditions, the study aims to answer a pressing question: Can trees shield farmers from deadly heat?

“The need for this research is dire. Farmers are increasingly vulnerable to heat-related illnesses such as dehydration, chronic kidney disease, and cardiovascular strain,” said Dr Chiwanga.

“The absence of shade or cooling infrastructure makes heat stress a major obstacle to both well-being and productivity,” she added.

Researchers are using innovative tools to gather evidence as farmers are observed in their daily routines while wearing sensors that monitor body temperature and heart rate.

She said urine and blood samples are also analysed to assess long-term health impacts.

By comparing data from farmers practising agroforestry with those who do not, and using advanced climate sensors, the team sought to determine precisely how trees help protect health.

Head of the Department of Sociology and Anthropology at the University of Dar es Salaam and co-researcher, Dr Richard Sambaiga, said community participation was crucial.

“Farmers have welcomed the wearable technology, showing strong engagement. Ethical approvals were secured without difficulty, and the detailed weather data collected in the first phase has laid a solid foundation for the next stages,” he said.

He emphasised that community sensitisation and involvement have been central to the project’s early success.

Beyond the immediate findings, KISHADE is also strengthening local capacity by training young Tanzanian researchers in advanced scientific and field methods, ensuring long-term benefits.

The project’s outcomes are expected to influence not only farmers but also policymakers, health professionals, and government agencies.

Non-governmental organisations and international partners stand to benefit from new insights into nature-based climate adaptation.

At the same time, donors will gain evidence on the value of investing in environmental and health resilience.

The data on microclimates and human health will contribute to global research on planetary health, with lessons applicable in other heat-stressed regions.

Farmers are already noticing changes, as Mr Henry Mubi from Kongwa District in Dodoma says, “The heat is unbearable. It shortens our working hours and makes farming harder.”

“We suffer headaches, fatigue, and dizziness. With fewer working hours, income falls too. But crops planted in shaded areas survive longer during heatwaves,” he added.

An occupational health expert from the World Health Organisation (WHO), Dr Ivan Ivanov, described the research as a landmark effort.

“This is a vital contribution to understanding how nature-based solutions can safeguard human health in a warming world,” he said.