1. Trees and Dietary Diversity in Africa
Amy Ickowitz
September 23, 2013
Presentation for Science Forum 2013, Bonn, Germany

2. Hypothesis: Trees and Forests are important
for dietary quality (dietary diversity)
Collection of nutritious NTFPs
Farming mosaics may promote
more diverse diets
Agroforestry and fruit
production
Ecosystem services of forests for
agriculture
Availability of fuel wood
May provide ‘back up’ foods for
lean season

3. Some implications, if true
• Forests may be relevant for food security/nutrition discussion not
only because of potential conflicts with another SLO, but because
might be of direct importance to nutrition as well
• Choices that are framed as food security/nutrition or conservation
are more complex (especially relevant for govt policy)
• We may need to fundamentally rethink the way we do our
research ….title of this Science Forum

4. Is there evidence?
Several recent papers discussing some of these plausible links
(Colfer et al., 2005; Vinceti et al., 2008; Arnold et al., 2011), but little
data to support
Recent paper by Johnson et al. (2013) finds that net forest loss
associated with less dietary diversity in Malawi
Also, it is plausible that there might be a negative association

5. Testing the hypothesis
• Study using DHS data from 21
countries integrated with GIS
data on % tree cover to
estimate the relationship
between tree cover and child
nutrition indicators (Ickowitz,
Powell, Salim, Sunderland,
under review)
• CIFOR project collecting dietary
intake information from
mothers and children in study
sites in 5 African countries

6. Study using DHS data
We Integrate:
• nutrition data from Demographic Health Surveys
with
• % tree cover data from GLCF (2003 and 2010
MODIS data at 250 m resolution)
(as well as other sources for other controls)
to investigate whether there is a statistically
significant relationship between indicators of
dietary quality and tree cover

7. Sample: about 93,000 children between ages 13
and 59 months in over 9,500 communities
(21 countries )

8. Regressions
• 3 Dependent Variables:
DDS; Fruit & Vegetable consn; Animal Source
Food consn
• Independent Variables:
% Tree Cover and % Tree Cover2
Mother’s education
Father’s education
Wealth Index
Rural Dummy
Child age & age2 & age3
Distance to Rd
Distance to closest city of 10,000
Aridity Index
Elevation
Sex of child
Currently breastfeeding
Month of interview
Country dummy

9. Results
• There is a statistically significant positive relationship between % tree
cover and Dietary Diversity (as proxied by DDS)
• Fruit and Vegetable Consumption first increases and then decreases
with tree cover (peak tree cover is about 45%)
• There is no statistically significant relationship between tree cover
and Animal Source Foods

10. Where are we now?
• The results of the DHS study give
an indication that there are
interesting relationships, but are
far from offering an explanation
• DHS data are coarse
• The GIS data don’t tell us the
kinds of trees
• Data can’t explain WHY
children in areas with more
trees have more diverse diets
• Country level regressions give
heterogenous results
• So….

11. Nutrition and trees in sub-Saharan Africa: A
Regional Comparative Study
• Collect data with more detailed
dietary info. and on where the food
actually comes from (forests,
fallows, agro-forests, farms, etc.)
• Compare diets in villages with
varying % of tree cover in
different regions of Africa:
Uganda, Ethiopia, Cameroon,
Zambia, Burkina Faso
• Two year project
• Already begun; preliminary
results available by end of
2014

12. Conclusions
We have found a statistically significant relationship between
tree cover and dietary diversity in a large sample of African
children
This gives preliminary support to the hypothesis that
forests are important for nutrition in Africa
We need more detailed and fine-grained data to help us to
understand how and why children in more forested areas
in Africa have higher dietary diversity
We hope that our findings, in conjunction with recent findings
from Bioversity, WorldFish, USAID, and ICRAF can help to
convince the CG to look at the wider landscape (in addition to
agriculture) in thinking about nutrition and health

13. Influencing the agenda?
•
•
•
•
•
Discussion Paper: starting
point for engagement
Representation at numerous
international events (FAO,
Leverhulme, IUNS, CGIAR
Science Meeting)
Collaboration with CRP4 –
flagship proposal on
“nutrition-sensitive
landscapes”
Clear contribution to SLO’s
Engaging with the wider
CGIAR!
THINKING beyond the canopy

14. Thank you!
THINKING beyond the canopy