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Provision of woodfuel is an important ecosystem service of dry forests and woodlands. However, charcoal production through selective logging of preferred hardwood species has the potential to alter the physiognomic composition of the residual or re-growth woodlands and may lead to their deterioration and degradation. This study, conducted through forest inventory in Mutomo District in Kenya, assessed the impact of charcoal production on unprotected dry woodlands in terms of tree density, targeted species basal area, species richness, evenness and Shannon diversity. The parameters of the disturbed woodlands were evaluated for significant differences with those of the neighbouring protected Tsavo East National Park, which served as a reference for an ecologically undisturbed ecosystem. By evaluating a consequence of tree harvesting for charcoal production, this study confirmed the overall significant differences between the protected and unprotected woodlands in all the tested parameters. To confirm if the differences in the land-covers of the woodlands had any influence on their degradation, all mentioned parameters were compared between the four differentiated classes and their respective control plots in the protected areas. At the "land-cover level", the statistically significant difference in the basal area of tree species preferred for charcoal production between the protected and unprotected open trees confirms that the class with a high density of large mature trees is the prime target of charcoal producers. In addition, there seems to be a general trend of lower values of tree species richness, evenness and Shannon diversity for the unprotected woodlands subjected to charcoal production. On the other hand, the disturbed woodlands display the potential to recover through their comparably high saplings density. The findings make an important contribution to the discourse on the impact of charcoal production in dry woodlands, a topic that is highly controversial among researchers.

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Agroforestry systems in Sub-Saharan African drylands are complex and heterogeneous in nature even under similar biophysical conditions. This can be attributed to household needs and socioeconomic status which influence the species and utility of the adopted trees. This has an impact on the trees establishment and management system through planting or Farmer Managed Natural Regeneration (FMNR). This study evaluates how trees for different utilities are managed and which socioeconomic factors influence these decisions. The study used primary data collected in Mutomo District, Kenya through a household survey based on a structured questionnaire. A paired sample t-test was done to assess the preferred mode of adopting trees for different utilities while factor analysis was used to characterize the households as either planting trees or practicing FMNR. Multiple linear regression using household regression factor scores as independent variables and socioeconomic indicators as dependent variables was done to ascertain which socioeconomic factors affect tree adoption. The results show that trees planted were mostly exotic species valued for their nutrition and commercial value, while FMNR was used for subsistence products and environmental services. Household size, livestock levels and mobility had a positive correlation with tree planting, while income, access to markets and roads had an inverse correlation. Access to natural woodland, distance to the nearest motorable road and land size had a positive correlation with tree protection. It is hoped that this knowledge will act as a reference point when designing agroforestry projects in similar areas to ensure they are more aligned to specific site and household conditions.

Charcoal is an important urban fuel; however, when production is unregulated, it is a major cause of land and forest degradation. Production through selective harvesting of the preferred large, hardwood tree species leads to a degraded residual forest or woodland composed of juvenile hardwood trees and unused softwood tree species. This situation can be addressed by ensuring that the rate of preferred tree species extraction does not exceed the mean annual increment. This study estimated the sustainable rate of tree harvesting for charcoal in Mutomo District, based on field data collected between December 2012 and January 2013, through a forest inventory. The woodlands are subjected to selective logging for charcoal production, an activity undertaken by about half of the residents for their livelihood. The study findings show that charcoal production through selective logging has led to a reduction of the hardwood trees biomass density to 3.8 t ha−1 compared with an estimated desirable level of 12.5 t ha−1. The results also show that it would take between 25 and 31 years for the woodlands to recover to the desirable stocking level if harvesting was completely stopped. This duration would increase to between 54 and 64 years if 80% of the mean annual increment was harvested for charcoal production and 20% was retained for woodlands recovery. As the residents of Mutomo District are poor and highly dependent on charcoal production for their livelihood, a harvesting plan based on the latter option would set the woodlands on the path to recovery and ensuring a sustainable livelihood source.

Many developing countries, Kenya included, want to diversify their domestic energy supply hence reduce dependence on highly volatile fossil fuel prices, enhance access to energy in rural areas, promote rural development and to reduce carbon emissions. This study was done to assess the potential for supply of biofuel feedstock for bioethanol and biodiesel production for domestic consumption and export. To achieve this, key feedstocks were identified and their environmental suitability, production and yields analyzed. Gross margin as a tool was used to make an economic analysis of the production of the feedstocks compared to that of the most prominent food and cash crops. A review of the national biofuel strategies, policies and regulations currently adopted in Kenya was also done. The study established that sweet sorghum and castor are the most environmentally suitable bioethanol and biodiesel feedstock respectively. In terms of gross margins, sweet sorghum has the highest gross margin at KSh 67,584 followed by sugarcane at KSh 37,746 and cassava at KSh 20,240 per hectare for bioethanol feedstocks. For biodiesel feedstocks, sunflower has the highest gross margin at KSh 2,921 per hectare. It is expected that this study will play a significant role in guiding the policy makers in making important decisions to drive the biofuels sector forward.

PDFThe titles of the Working Paper Series are intended to disseminate provisional results of agroforestry research and practices and to stimulate feedback from the scientific community.Other World Agroforestry publication series include Technical Manuals, Occasional Papers and the Trees for Change Series.