Trees and Dietary Diversity in AfricaAmy Ickowitz

September 23, 2013

Presentation for Science Forum 2013, Bonn, Germany

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

• 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

Some implications, if true

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

• 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

Testing the hypothesis

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

Study using DHS data

Sample: about 93,000 children between ages 13 and 59 months in over 9,500 communities

(21 countries )

• 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

Regressions

• 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

Results

• 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….

Where are we now?

• 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

Nutrition and trees in sub-Saharan Africa: A Regional Comparative Study

� 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

Conclusions

THINKING beyond the canopy

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

Thank you!