Agroforestry satisfies household energy needs
Growing multipurpose trees on farms provides households with an affordable and convenient source of firewood and significantly lightens the workload of women and children. These were among the findings of a 2015 study carried out in Kenya by scientists from the World Agroforestry Centre. The study compared the contribution of agroforestry to firewood consumption for 40 households in Kibugu village, Embu County, on the flanks of Mt Kenya, and the same number in Keraita village in Kiambu County, at the foot of the Aberdares.
Large numbers of farming families have adopted agroforestry in Embu, frequently intercropping timber and fruit trees in their tea and coffee gardens, and planting trees along farm boundaries. Four trees are favoured in particular: Grevillea robusta, macadamia, avocado and eucalyptus. In contrast, farming households in Kiambu have had little experience of agroforestry and have relatively few trees on their farms. “When you’re there, you can see for kilometres,” says Mary Njenga, who led the research.
Njenga and her colleagues found that 40% of the surveyed households in Embu harvested all their firewood needs from their farms. In contrast, just 5% of households in Kiambu got all of their firewood from their own land. The rest – in both study sites – either bought their firewood from merchants, or harvested it themselves from nearby forests. “In the past, people used to go to the edge of the local forest and collect residues from the forest floor,” says Njenga. “But now, because of overharvesting, they are forced to go deeper into the forest to find fuelwood, and in Kiambu they walking over 4km in both directions just to get one load.”
This can be immensely draining for those involved, as Njenga discovered when she accompanied a group of women to the harvesting sites. Before leaving home, most of them took just a cup of tea for breakfast. It then took them an hour and a half to get to the forest, the same amount of time to gather a 54kg load, and another hour and a half to return home. Frequently, they were accompanied by children, who help to collect the wood.
Besides the burden involved in collection, the women were also losing income. “If a woman works from 8.00am to 1.00pm – for example labouring in fields – she earns the equivalent of US$2.5 in wages,” says Njenga. Each time they spend the morning collecting firewood, they are effectively forgoing the chance of earning that money. These are the opportunity costs of each trip.
Firewood harvested from trees on farms, such as the prunings of Grevillea, can be stacked and dried before being used. In contrast, families who harvest their firewood from the forest tend to use it immediately. All too often, it is high in moisture, burns poorly and emits more smoke with noxious gases than firewood which is dry.

The study shows that agroforestry can play a major role in satisfying household energy needs. Njenga also points out that families that use more efficient cooking stoves require less firewood than those using traditional stoves. So, they should ideally, combine growing trees on farms with more efficient cooking stoves.
Reference
- Njenga M et al. 2015. Innovations in Affordable and Clean Tree-based Cooking Energy Systems in Sub-Saharan Africa