SEEING THE WOOD FOR THE TREES:beyond bio-forﬁcation: nutrion, cooking & health
SEEING THE WOOD FOR THE TREES:beyond bio-‐for,ﬁca,on: nutri,on, cooking & health Dr A B (Tony) Cunningham ICRAF Senior Associate & School of Plant Biology, University of Western Australia
OVERVIEW • 1. Context • 2. Why worry about what’s used for cooking? • 3. Where does solid fuel use for cooking occur? • 4. Common intervenAons; • 5. Fuel choices, toxic eﬀects & agroforestry soluAons • 6. Conclusions.
1. CONTEXT • “Hidden hunger” – micro-‐ nutrient deﬁciency; • “nutriAon transiAon” & bioforAﬁcaAon in further dietary simpliﬁcaAon vs. biodiversity in nutriAon (Frison et al., 2004, COP7; Johns and Eyzaguirre. 2007); • Looking out of the frying pan & into the ﬁre….(or at fuelwood & charcoal diversity)….
WHAT SCALE? CASE STUDY: TANZANIA & MALAWI • About half of Tanzania’s annual consumpAon of charcoal takes place in Dar es Salaam (c.500,000 tons/yr) from a “catchment” up to 200 km away (WB, 2009); • Tanzania: trade worth US$650 million/yr (WB, 2009) & in Malawi c. US$41.3 million/yr to four ciAes (=tea industry) (Kambewa et al, 2007); Ref: World Bank. 2009. Environmental crisis or sustainable development opportunity?: Transforming the charcoal sector in Tanzania. • World Bank, Washington DC.
2. BACKGROUND • 2.4 billion people live in households where solid biomass fuels (wood, charcoal, dung) are used for cooking & heaAng plus 0.6 million using coal (Po et al., 2011); • About 2 million children/yr die of pneumonia. Smoke (=indoor air polluAon) increases risk of pneumonia by 1.8 in children (Dherani et al, 2008; Hu et al., 2010; Po et al., 2011); • Not all woods are the same: toxins in fuelwoods can have serious health consequences.
3. WHERE DOES SOLID FUEL USE FOR COOKING OCCUR? but what about tree diversity & fuelwood & charcoal quality? • Ref: Torres-‐Duque et al. 2008. Biomass Fuels and Respiratory Diseases. Proc Am Thorac Soc 5: 577–590
4. COMMON INTERVENTIONS • improvements of household venAlaAon; • IntroducAon of diﬀerent stove designs; • TransiAons to other energy sources (e.g: rural electriﬁcaAon); • …but charcoal & fuelwood sAll widely used, even with rural electriﬁcaAon.
CASE STUDY: SOUTH AFRICA • electriﬁcaAon yet no signiﬁcant decrease in per capita woody biomass consumpAon…BUT: • signiﬁcant increase in the Ame spent collecAng fuelwood & more buying ﬁrewood; • larger number of tree species collected & used for fuelwood than before…..so wood use will be with us for a while…. REF: Madubansi M & Shackleton C.M. (2006). Changing Energy Proﬁles and consumpAon pakerns following electriﬁcaAon in ﬁve rural villages, South Africa. Energy Policy. 34:4081-‐4092
5. FUEL CHOICES & TOXIC EFFECTS • What is used to cook foods by which households & what levels of exposure to what types of smoke?; • Toxic eﬀects of certain plant species, genera & families well known (eg: Spirostachys (Africa), Excoecaria agallocha (South Asia) which contain the diterpene excoecarin; • More subtle eﬀects can be more insidious.
SMOKE IS NATURAL, BUT IS IT GOOD? • Polycyclic aromaAc hydrocarbons (PAH) (e.g: benzopyrenes) = carcinogenic (cancer of lungs, pharynx & larynx); • Polycyclic aromaAcs & metal ions in smoke (toxins absorbed into eye lenses, causing oxidaAve change & cataracts); • Need to understand mutagenicity emission potency of diﬀerent wood species are used as fuel.
SEEING WOOD, TREES & LANDSCAPES less choice of fuelwoods, parAcularly for poor & vulnerable households
COMBINE WOOD MUTAGENIC ASSESSMENTS & LOCAL KNOWLEDGE • mutagenic potency of some fuelwood species has been established (e.g: Vu et al., 2012, Portugal) but more Asian and African studies needed; • Good to use informant-‐based valuaAon systems & local knowledge to prioriAze fuelwood species (Cunningham, 2001); • Euclea as an example.
CASE STUDY: STRYCHNOS, 5 YR FAMINE FOOD • Highly favoured woods: Newtonia hildebrand9i, Pteleopsis myr9folia vs. poor quality woods (e.g: Albizia versicolor) (Cunningham, 1985)
AGROFORESTRY & SELECTING “GOOD WOODS” • SelecAon for chemotypes with low toxic levels (e.g: polycyclic aromaAc hydrocarbons) -‐ parAcipatory processes & local knowledge important
6. CONCLUSION: A SYSTEMS APPROACH FOOD & FUELWOOD FOOD & FUEL ACCESS AVAILABILITY • Social networks; • RestoraAon, agroforestry & • Income to buy food & fuel; Resource management • Disease impacts on capability (malaria, respiratory diseases, HIV); • availability of quanAty & quality • Direct & indirect impacts of fruit, fuel & fodder PEOPLE’S of climate on land-‐use species & food security. WELL BEING NUTRIENT ACCESS • Nutrient content of foods (oils, proteins, vitamins); * Opportunity to boil water & cook foods; • Indirect eﬀects on human health & ability to absorb nutrients (fungal & fuel toxins, water & sanitaAon)