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The shea tree (Vitellaria paradoxa C.F. Gaertn.) is an important tree species in agroforestry systems in West Africa and shea nuts constitute a fundamental resource for rural livelihoods in this area. This study investigated the sustainability and interactions in agroforestry systems of shea trees around the village Nakpalli in Northern Ghana. The focus of the study was the population structures and densities of shea trees on different land types, below-canopy microclimate and co-cultivation of yams (Dioscorea rotundata (Poir.) J. Miége) under shea tree canopies, and water stress of the trees in the driest season. Shea tree populations are overall well-conserved in this area, but Weibull-distributions of the tree populations and quantification of seedlings showed a lower tree density in both cultivated and fallowed lands, as compared to undisturbed bushlands. Although farmers may deliberately manage the density of larger trees, the low densities of seedlings and saplings indicate that intensified management practices, including shortened fallow periods and intentional clearing of land by fire before sowing, might negatively affect the long-term regeneration of the shea trees. Co-cultivation of yams below shea tree canopies allowed production of 11.5 t/ha as compared to 20.8 t/ha at open field conditions. The lower yields may have been caused by an almost 74% reduction of photosynthetically active radiation below canopies, relative to outside the canopies. Shea trees in the fields, fallows and bushlands had close-to-zero predawn leaf water potentials, indicating low water stress, even in the middle of the dry season. Thus, shea trees are both well-adapted and highly valued in this area, which underlines the importance of conserving this indigenous tree species in the agroforestry systems of northern Ghana. [ABSTRACT FROM AUTHOR]

Agroforestry parklands are an age-old traditional land use practice that integrates crop cultivation under scattered woody plants. This practice is widespread in West African savannas providing many essential ecological and socio-economic benefits to people such as food, fuelwood, and medicine. Currently, parklands are decreasing due to changes in agriculture and land use practices, often associated with human population growth. Understanding spatial patterns as well as identifying reliable methods of sampling to estimate the density of woody plants is necessary for the sustainable management of parklands. In this study, a comparative analysis of select plotless sampling methods was performed using field and simulated datasets with known spatial patterns from field assessments. Results of spatial indices tests indicated that woody plants in parklands exhibited two spatial patterns: i.e., aggregate and random, the latter being the dominant pattern observed in field datasets. Based on relative measure statistics (i.e., RRMSE and RBIAS), the ordered distance (OD), point-centered quarter (PCQ), and closest individual (CI) methods performed well when woody plants were located in a random pattern while the variable area transect (VAT) method was better at estimating density under patterns of spatial aggregation. Overall, OD and VAT methods are recommended for density estimation in parklands because they are relatively more accurate, less biased, and practical and computations are easy to undertake. [ABSTRACT FROM AUTHOR]

Agroforestry parklands, characterized by scattered trees growing within cultivated crop fields, are the most widespread agricultural system in semi-arid West Africa. Agroforestry trees offer many ecological and socioeconomic benefits, such as added income, food, and medicine. They are currently under threat in this region due to recent changes in agricultural and land use practices. For example, a reduction in traditional fallow rotation periods has led to decreased regeneration of a common agroforestry tree, shea (Vitellaria paradoxa), which has been an important economic resource for women. The aims of this study were to determine beneficial spatial distributions of shea to maintain high yields of staple crops and to better understand male and female farmer perceptions of shea maintenance. We compared maize (Zea mays) vegetative growth, grain yield, soil moisture, and light availability associated with individual shea trees and clumps of trees on five farms in Ghanaian agroforestry parklands. We also interviewed local farmers to better understand their management perspectives. Maize vegetative growth increased with light availability, but was not limited by soil moisture. Conversely and contrary to farmer perceptions, grain yield was not influenced by light availability, but increased with increasing soil moisture. Also contrary to common beliefs of local farmers, grain yield was greater under clumps of shea compared to scattered distributions of individual trees. We therefore recommend the maintenance of clumped distributions of shea, as they provide beneficial microclimates for staple crops, and could assist in improving the productivity of shea products that are considered the domain of women farmers. [ABSTRACT FROM AUTHOR]

The potential for the development of shea industries to increase women's incomes is the focus of a number of development interventions in rural West Africa. However, concerns have been voiced over the potential effects of increased commercialization on women's rights over this resource. This study examines women's participation and rights over shea production in a context of increasing commercialization in northern Ghana through a survey of 90 producers and eight oral histories. Although shea incomes are frequently described in the literature as falling under women's control, joint spending decisions for shea income were reported by half of the married women surveyed. This does not appear to be an outcome of growing assertion of men's rights over shea trees themselves but rather is explained, by women, largely in relation to their husbands' involvement in nut production. [ABSTRACT FROM AUTHOR]