Complexity lives at the tree–people–planet interface
In their editorial review for a special edition of the journal Current Opinion in Environmental Sustainability, Mark Stafford Smith of CSIRO and Cheikh Mbow of World Agroforestry Centre (ICRAF) give compelling examples of the complex challenges the agroforestry researcher works through in analyzing the interactions between people, trees and agriculture. The complexity arises in large part because the interactions happen within dynamic landscapes that are also influenced by policy decisions, market forces, and climate change.
“These social–ecological interactions are not mutually exclusive and require systemic approaches,” say the authors, who based the editorial on the 23 articles published in the special journal edition.
Take for instance the issue of drivers (causes) of deforestation in Africa. These are intimately linked with the growing demand for commodities, fuelwood and charcoal, and could be addressed through sustainable intensification using agroforestry practices. Yet this growth in demand, itself, can also encourage on-farm intensification, by stimulating the market.
On the issue of gender equity, agroforestry has the potential to offer substantial benefits to women, e.g. by bringing fuelwood close to the home. These gender outcomes happen at the same time as trees on farms provide households with nutrition, income from non-timber products (e.g. shea fruits), and a range of ecological services.
Referring to soil fertility, Stafford Smith and Mbow emphasize the importance of nitrogen-fixing trees in agro-ecosystems to support healthy and fertile soils. The supported vegetation can contribute positively to hydrological cycles, as improved tree biodiversity is able to promote nutrient recycling and water fluxes, they note. However, there is a need for improved management of the system in order to avoid the release of nitrous oxide or other greenhouse gases into the atmosphere.
The right trees on farms have been shown to enhance the resilience of smallholder farmers to climate impacts, by performing both biophysical and socio-economic roles. Yet agroforestry systems are also affected by climate change, and as such, need to be designed and adapted within integrated approaches.
Another complex issue is policy. Enabling policies can open up opportunities, including markets in ecosystem services such as biocarbon projects (in which carbon payments are made to farmers using sustainable agricultural practices). Yet farmers say non-carbon benefits, such as food security and income generation, are more important to them than carbon rewards. Such issues need “a deeper understanding of the roles of agroforestry, as well as policy actions to enhance smallholder farmers’ capacity to adapt to climate impacts,” says the editorial review.
Practitioners also need to bear in mind that one size does not fit all; suitable tree species, seed and extension/support services that take into account the farmer’s locality and socioeconomic situation are needed. Yet even with these in place, ‘closing the yield gap’ may sometimes require the correction of soil deficiencies that may not yet be well understood.
On a broader scale, there are teleconnections, such as the dependence of West African rainfall on evapotranspiration in East Africa. “The influence of tree cover on rainfall and the water cycle is very location-dependent and it needs local, but long-term monitoring to understand,” say the authors.
Strafford Smith and Mbow note that these complexities are not unique to agroforestry research, but occur “wherever research aims to bring development issues together with global change science.”
Through embracing a holistic view of agroforestry, researchers can take “a long view of social-ecological systems, and seek to understand the trade-offs that farmers consider in their decision making.”
The complexities notwithstanding, the tone of the editorial is optimistic, and many success stories of sustainable agroforestry systems are testament to this. In Africa, examples include raising and stabilizing of maize yields through the use of ‘fertilizer trees’ in southern Africa; high increases in milk production aided by fodder trees and shrubs and other interventions in the East Africa Dairy Development project; a dramatic re-greening of Sahelian parklands through farmer-managed regeneration of trees; and participatory tree domestication success in the West and Central Africa.
All in all, “agroforestry can assist the challenges Africa faces with food, water and energy security, equity, poverty and environmental degradation,” state the authors.
Read full editorial overview:
Mark Stafford Smith, Cheikh Mbow, Editorial overview: Sustainability challenges: Agroforestry from the past into the future, Current Opinion in Environmental Sustainability, Volume 6, February 2014, Pages 134-137, ISSN 1877-3435, http://dx.doi.org/10.1016/j.cosust.2013.11.017. (http://www.sciencedirect.com/science/article/pii/S1877343513001784)
The article appears in a special issue of the journal Current Opinion in Environmental Sustainability on the theme ‘Sustainability challenges.’ The full special issue is available Open Access at http://www.sciencedirect.com/science/journal/18773435/6/supp/C
The issue is edited by Cheikh Mbow, Henry Neufeldt, Peter Akong Minang, Eike Luedeling and Godwin Kowero. It will be launched during the World Congress on Agroforestry, Delhi, February 2014.
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