Over the course of the project, we have provided solid evidence on how forests and trees affect people’s diet in Africa. We have adopted an innovative multi-scale research design to provide both broad scale evidence and detailed local level insight.
At the broad scale, we found that even low levels of tree cover improve people’s dietary quality in West Africa. Specifically, we find that the probability of consuming vitamin A–rich foods increases with an increase in tree cover. These findings were based on data from more than 15,000 households across 10 West African countries.
Also at the broad scale, we found that tree plantations and forest regrowth are linked to poverty reduction across 18 African countries. By combining a recent map that distinguishes tree plantations from regrowth from 2000 to 2012 with multidimensional poverty measures from more than 200,000 households, we found a positive association between people's living standards and areas where tree plantations have expanded or, to a lesser extent, forest regrowth has occurred.
We also combined the new map on forest regrowth with food consumption panel data from Nigeria from 1100 households. We found that people living in areas where forest regrowth has occurred have a higher intake of fruits and vegetables and thus higher dietary diversity.
Using panel data from Tanzania, we were able to estimate how deforestation affects people’s dietary quality. We found that deforestation caused a reduction in fruit and vegetables consumption of 14g per day per person, which represents 11% of average daily intake. We also conducted a detailed longitudinal study in Tanzania to explore how changes in food environments have shaped the acquisition and consumption of wild foods among people living near forests. We used data collected in both the dry and rainy seasons in 2009 and 2021/2022. We found that the proportion of people who collected wild foods within the past seven days had declined from 90 to 61% in the dry season and from 99 to 72% in the wet season. The main reasons were 1) decreased availability caused by, for example, loss of biodiversity, 2) lack of access due to government forest regulations, and 3) increased desirability towards marked-based foods .
Analogously, we used panel data from Malawi to examine the effects of trees on farms on people's dietary quality. We found that having on-farm trees leads to higher and more diverse fruit and vegetable consumption. Specifically, households who had trees on their farm exhibited a 3% increase in vegetable consumption compared to households without trees. Moreover, for every additional tree species owned or acquired by a household during the study period, fruit consumption increased by 5%. In Malawi, we also linked detailed survey data from 460 households to high-resolution tree-cover data. We found that women from households that source food from on-farm trees have higher levels of zinc, vitamin A, iron and folate adequacy compared with women from households that do not source food from on-farm trees. For example, women sourcing food from trees on their farms have on average 8–15% higher folate adequacy, depending on the season.
