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Natural populations or landraces contain a high level of genetic variation that can be used for the selection of plus trees in Faidherbia albida agroforestry parklands in the Sudano-Sahelian zone of Cameroon. With the high rate of deforestation and overpopulation in recent times, there is the danger of losing these naturally adapted landraces of trees. This study investigates the influence of environmental conditions (altitude, human activity, rainfall and soil types) on four (Kodex, Mambang, Dinao and Parkine) Faidherbia albida agroforestry parklands in Cameroon. A forest inventory sampling method with a set of 33 plots 200 m in diameter was established in the parklands to collect data. Phenotypic measurements (height, diameter at breast height, number of branches, crown diameter and calculated biovolume) were taken and leaf phenology was observed on 156 trees in addition to environmental conditions of the parklands. Species diversity was recorded only in the transects of Kodek and Parkine agroforestry parklands during the inventory. Significant differences were observed among the agroforestry parklands, the soil types, altitude, and human activities on the morphological parameters measured. The inverse phenology of Faidherbia albida was observed in three of the parklands with Mambang still conserving its leaves in the rainy season. A total of 1904 trees (1233 from Kodek and 671 from Parkine) were recorded during the species diversity inventory process from 63 species with Parkine parkland being the most diverse in species types with Shannon H = 2,058 index at Kodek and Shannon H = 2.53 index at Parkine. The results of this study indicated that diverse environmental conditions do exist in these parklands and have influenced the measured parameters. This information can aid in the selection of plus-trees for breeding, conservation and management of the species while the information on species diversity will assist in monitoring the dynamic of the parklands. [ABSTRACT FROM AUTHOR]

As the rate of forest degradation continues to rise, agroforestry systems may serve as a way of conserving species and carbon sinks. The aim of the study was to assess the contribution of Daniellia oliveri agroforestry parklands to the mitigation of climate change via the estimation of carbon stock in the Sudanian-Sahelian zone of Cameroon. To achieve it, an ecological study was carried out. A total area of 144 ha has been established in Daniellia oliveri agroforestry parklands. To meet this objective, the diameter at breast height of trees in Daniellia oliveri parklands was measured with regard to their age. Thus, allometric equations and the ascending hierarchical classification were used for the assessment of carbon stock and determination of the typology of Daniellia oliveri agroforestry parklands in the study area. The results show that Daniellia oliveri agroforestry parklands harbor 61 species belonging to 48 genera and 45 families. The carbon stored in Daniellia oliveri agroforestry parklands differs according to their age. It varies from 85.44±11.11 tC/ha for 1–10 year in young parklands to 236.55±4.96 tC/ha for those ≥30 years old. Carbon sequestration potential fluctuates from 312.71±40.77 CO2eq/ha for young parklands (1–10 years) to 865.77±18.20 CO2eq/ha in old one (≥30 years). The typology of Daniellia oliveri agroforestry parklands indicates the existence of three categories of parklands among which; type 1, the most representative of the area (52.78%) and capable of generating significant income. This study greatly contributes to the understanding of the usefulness of Daniellia oliveri agroforestry parklands for carbon sequestration. Actions to strengthen the protection of the trees of this ecosystem must be considered to minimize its long-term degradation and so that it can be a more sustainable source of carbon sequestration.

Tree growth is an important means of capturing and storing atmospheric carbon and is thus a key to mitigating the effects of climate change. Over recent decades, mango (Mangifera indica L.) parklands have expanded in Burkina Faso, due to the species’ fast growth and its compatibility with local agricultural crops. However, the contribution of mango parklands to reducing atmospheric CO2 remains unknown, due to the lack of local tools for aboveground biomass (AGB) estimation. The aim of this study was to develop accurate allometric equations for estimating the AGB and carbon (C) stocks of mango parklands. A field survey was carried out to select mango parklands according to their age. These parklands were then classified into six groups age (0≦y

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]

National food security has been a major policy goal in Sudan since the country gained its independence in 1956. One of the fundamental reasons is to ensure the social welfare for people living in rural areas. In this study we aimed to analyse how farmers secure their food and generate income in the semi-arid Sennar state in Sudan, using two selected sites, El Dali and El Mazmum, as examples. We interviewed 281 randomly sampled household heads, of which 145 at El Dali and 136 at El Mazmum, between July and November 2011. We identified four distinct land use systems, of which three consist of monocropping and one of cultivation in agroforestry parklands. Several statistical techniques and economic analysis were applied on the study data. Our results show that, in the two areas, the highest average yields over a 10-year period for the three crops studied, sorghum, pearl millet and sesame, were achieved in agroforestry system, except for the case of sesame at El Mazmum. Economic returns for the farmers, as indicated by net present value or benefit/cost ratio, followed the same pattern. The study concludes that farmers should rely more on agroforestry to improve their food security and cash income generation. Land use and land right policies, which currently discourage farmers from growing trees on their lands, should be revised, so as to give more incentive to them to adopt ecologically and economically more sustainable land use practices. [ABSTRACT FROM AUTHOR]

Shea ( Vitellaria paradoxa) is an important fruit tree in West African parklands, and its successful pollination is a requirement for fruit production. Size-based pollinator exclusion experiments combined with visual observations showed that presence of honey bees ( Apis mellifera jemenitica) was important for pollination and thereby the production of fruits and seeds. Smaller insects, mainly species of stingless bees ( Hypotrigona spp. and Liotrigona cf. bottegoi) and solitary bees ( Compsomelissa borneri) could partly compensate pollination in absence of honey bees, but fertilisation and fruit yield was reduced. A positive correlation between fertilisation percentage and number of honey bee colonies within radii of 900 and 1000 m was observed. The percentage of fertilisation and number of mature fruits per fascicle were higher in trees with colonies of stingless bees in the trunk when honey bees were excluded by bagging. We conclude that local beekeeping with honey bees and stingless bees is likely to have a positive influence on fruit production of shea trees in the farmed West African parklands, which speaks in favour of a pollinator friendly environment. [ABSTRACT FROM AUTHOR]

Local iron production played a major role in the pre-colonial West African economy and certain metallurgical centres operated on an industrial magnitude. One of them is the Bassar area in central Togo where the onset of iron metallurgy is considered to date back to the 3 rd -4th century BC, even though only from the 14th century AD onwards the area experienced distinct production intensification. High-level iron production lasted as late as the early 20th century. Bassar iron metallurgy was often considered to have caused massive deforestation and vegetation degradation, mainly due to wood exploitation for charcoal production, specifically to fuel iron smelting furnaces. The study presented here is the first to test this assumption using anthracological methods, supplemented by ethnohistorical interviews and archaeometallurgical investigations. The focus of our investigations is on two sites, Tchogma and Tatré. The charcoal assemblages at both sites and during all production periods are dominated by trees and shrubs with dense wood. According to our ethnohistorical interviews, hard wood species were considered particularly suitable for iron smelting, including several species with a strong capacity to re-sprout after coppicing. The taxon composition of the charcoal assemblages from metallurgical waste heaps generally corresponds to the oral traditions. In addition to the taxa mentioned by the interviewees, useful fruit trees such as the shea butter tree ( Vitellaria paradoxa ) were regularly used as fuel for ironworking. This demonstrates the exploitation of agroforestry parklands, which is providing evidence that arable land was already occupying a vast land surface of the Bassar area. The results of our study seem inconsistent with the previous idea of massive vegetation degradation due to the impact of wood exploitation for iron metallurgy in Bassar. Three main factors contradict previous general deforestation assumptions: 1. The anthracological results indicate the use of taxa with the ability to re-sprout, which probably allowed for fast woodland regeneration; 2. We consider the area to possess a higher biomass reproduction capacity in comparison to areas further north investigated in our previous studies; 3. The development of local craft specialisation scattered the impact of wood use on the Bassar landscape, thereby, preventing complete local deforestation. Our re-evaluation of Bassar slag amounts indicates fuel consumption was higher than previously thought. The over-exploitation of certain preferred taxa, particularly species with a restricted capacity to re-sprout, and local vegetation changes around the smelting sites is likely, although such modifications are not unequivocally reflected in the charcoal data. [ABSTRACT FROM AUTHOR]

Agroforestry parklands, in which annual crops are grown under scattered mature trees, constitute the most prevalent farming system in semiarid West Africa, covering vast areas of land. The most dominant tree species in these systems is Vitellaria paradoxa , an indigenous tree to West Africa. Despite the importance of this tree in the region, no study to our knowledge has examined its sources and patterns of water uptake. In this study, we used oxygen stable isotopes at natural abundance levels to investigate water sources used by V. paradoxa both in the dry and wet season in an agroforestry parkland in Burkina Faso. We found that during the wet season soil moisture was highest near the soil surface (<10 cm depth), yet during this time V. paradoxa preferentially accessed water from slightly deeper soil depths, obtaining ca. 90% of its water from 10 to 50 cm depth. In contrast, soil moisture in the upper soil layers was significantly lower during the dry season and as a result V. paradoxa shifted to deeper water sources, obtaining ca. 30% of its water from groundwater and ca. 50% from 30 to 600 cm depth. We also found a negative relationship between tree size and the contribution of groundwater during the dry season, whereas during the wet season V. paradoxa predominantly used water near the soil surface regardless of tree size. Knowledge about the sources and patterns of tree water uptake provides crucial information to better understand how trees influence the local water balance. [ABSTRACT FROM AUTHOR]

After the severe droughts in the 1970s and 1980s, and subsequent debates about desertification, analyses of satellite images reveal that the West African Sahel has become greener again. In this paper we report a study on changes in tree cover and tree species composition in three village landscapes in northern Burkina Faso, based on a combination of methods: tree density change detection using aerial photos and satellite images, a tree species inventory including size class distribution analysis, and interviews with local farmers about woody vegetation changes. Our results show a decrease in tree cover in the 1970s followed by an increase since the mid-1980s, a pattern correlating with the temporal trends in rainfall as well as remotely sensed greening in the region. However, both the inventory and interview data shows that the species composition has changed substantially towards a higher dominance of drought-resistant and exotic species. This shift, occurring during a period of increasing annual precipitation, points to the complexity of current landscape changes and questions rain as the sole primary driver of the increase in tree cover. We propose that the observed changes in woody vegetation (densities, species composition and spatial distribution) are mediated by changes in land use, including intensification and promotion of drought tolerant and fast growing species. Our findings, which indicate a rather surprising trajectory of land cover change, highlight the importance of studies that integrate evidence of changes in tree density and species composition to complement our understanding of land use and vegetation change trajectories in the Sahel obtained from satellite images. We conclude that a better understanding of the social-ecological relations and emerging land use trajectories that produce new types of agroforestry parklands in the region is of crucial importance for designing suitable policies for climate change adaptation, biodiversity conservation and the sustainable delivery of ecosystem services that benefit local livelihoods in one of the world’s poorest regions. [ABSTRACT FROM AUTHOR]

Agroforestry practices in Sudan take on various forms across the country, depending on the arrangement, distribution and integration of trees with agricultural crops and/or livestock. The study aimed to describe and analyse the arrangement of acacia trees with crops on parklands in El Dali and El Mazmum areas in Sennar State, Sudan. Specifically, an attempt was made to identify the determinants of integration of natural acacia trees with crops in mechanised rain-fed agricultural schemes forming agroforestry parklands. Another specific aim was to determine farmers' perceptions about the constraints of adopting such agroforestry practices were also determined. Data was collected using a social survey method, in which 50 % of the total numbers of villages was randomly selected after classification into small, medium and large villages. Moreover, 5 % of the heads of households in the selected villages were interviewed face to face. The number of respondents was 281. Logistic regression model results indicated that the number of household members, the administrative unit, the incentive received from agricultural union and the land size were the main determinants for integrating acacia trees with agricultural crops in mechanised rain-fed agricultural schemes forming the agroforestry parklands. Constraints related to the prevalence of agroforestry practices included the absence of extension services and planting materials, unfavourable tree tenure, the destruction of trees/crops by animals, and the practice of renting land for sole crop cultivation. Several suggestions are given increased adoption of sustainable agroforestry for more production farming. As a priority land tenure and tree tenure issues must be clarified. [ABSTRACT FROM AUTHOR]

Aims: Agroforestry parklands are an important agricultural practice in southern Mali where trees such as the Shea ( Vitellaria paradoxa C.F. Gaertn) improve soil fertility and crop growth. However, it is not known whether Shea trees can ameliorate Zn-deficient soils or improve Zn uptake from soils of high-Zn, mafic origin. Methods: A total of 22 Shea trees preserved in traditional parklands with sorghum ( Sorghum bicolor L. Moench) were selected from two soil parent material (PM) types (mafic and non-mafic). Sorghum grain and soil samples were taken along a transect from the bole to 12 m beyond the canopy and analyzed for soil and grain parameters including diethylenetriaminepentaacetic acid (DTPA)-extractable soil-Zn and grain-Zn concentration. Results: Zn-deficient soils were observed with most occurring at non-mafic PM. Mean DTPA-extractable Zn concentrations ranged from 0.55-2.98 μg g in mafic soils and 0.34-1.02 μg g in non-mafic soils. PM influenced soil available-Zn, but not grain-Zn concentration. Both soil available-Zn and grain-Zn concentrations decreased away from trees with grain-Zn concentration not consistently decreasing across all soils. Conclusions: These results suggest that Shea trees grown in soils derived from mafic PM can improve soil-Zn availability, but that other growth factors are more important in determining grain-Zn content. [ABSTRACT FROM AUTHOR]

Water scarcity constrains the livelihoods of millions of people in tropical drylands. Tree planting in these environments is generally discouraged due to the large water consumption by trees, but this view may neglect their potential positive impacts on water availability. The effect of trees on soil hydraulic properties linked to groundwater recharge is poorly understood. In this study, we performed 18 rainfall simulations and tracer experiments in an agroforestry parkland in Burkina Faso to investigate the effect of trees and associated termite mounds on soil infiltrability and preferential flow. The sampling points were distributed in transects each consisting of three positions: (i) under a single tree, (ii) in the middle of an open area, and (iii) under a tree associated with a termite mound. The degree of preferential flow was quantified through parameters based on the dye infiltration patterns, which were analyzed using image analysis of photographs. Our results show that the degree of preferential flow was highest under trees associated with termite mounds, intermediate under single trees, and minimal in the open areas. Tree density also had an influence on the degree of preferential flow, with small open areas having more preferential flow than large ones. Soil infiltrability was higher under single trees than in the open areas or under trees associated with a termite mound. The findings from this study demonstrate that trees have a positive impact on soil hydraulic properties influencing groundwater recharge, and thus such effects must be considered when evaluating the impact of trees on water resources in drylands. [ABSTRACT FROM AUTHOR]

This study examines farmers' knowledge and management of soil fertility and vegetation in Vitellaria paradoxa and Cordyla pinnata dominated agroforestry parklands in a Sudano-Sahelian region of Mali. Qualitative data from a series of semi-structured interviews were used to construct an empirically based typology of farmer practices. These interrelated practices center on famers' agroecological knowledge, decision-making, and cropping strategies and are conceptualized as variable and adjustable socioecological responses to environmental and socioeconomic contingencies. The typology categorizes farmers in terms of their capacity for managing parkland soil and tree resources in an ecologically sustainable manner while negotiating livelihood challenges. It identifies the ideal farmer as one who practices the following: (1) use of environmental knowledge that considers multidimensional relationships among ecological and social components of parkland systems, (2) agricultural techniques that adaptively combine aspects of intensive and traditional extensive agriculture, and (3) natural resource decision-making that explicitly includes women's environmental knowledge and livelihood strategies. [ABSTRACT FROM AUTHOR]

Despite their socio-economic and ecological role, many studies have shown that the parklands are degrading very rapidly. Therefore, there is a need to undertake restoration actions for both production and environmental services. To do so, there is a need to identify factors that are affecting the dynamics of parkland systems. The present study aimed at characterizing and quantifying tree diversity of parkland systems taking into consideration the household's wealth status, land uses, market access and the type of farming system (cereal based on the 'Plateau Central' and cotton based in 'Boucle du Mouhoun'). Six villages (Kienfangué, Ipelcé, and Kuizili with easy access to the market and, Karang-Tanghin, Nionsna and Targho with poor access to the market) in the 'Plateau Central' and six villages (Bondoukuy, Ouahabou and Yaho with easy access to the market and, Dora, Fakéna and Mamou with poor access to the market) in 'Boucle du Mouhoun' were studied. In each village, the Participatory Analysis of Poverty and Livelihood Dynamics method was used by rural farmers to rank farmer households of their communities and that gave three groups of wealth status that are poor, fairly well-off and well-off. Five households representing each of the three wealth groups in each village, giving a total of 15 households per village, were randomly selected by wealth group. Tree/shrub inventories were conducted in all land use types (house fields, village fields and bush fields) of the 180 selected households for the 12 studied sites. The number of species in the different land use types ranged from 96 to 102, but the majority of species were represented by less than 10 individuals. This indicates the selection effect made by the farmers to the parklands. Land use and farming system showed a clear effect on tree diversity in parklands. The effect of accessibility to market was evident in some cases whereas wealth status did not show any effect. Despite the statistical significant effect of farming system and land use type, the ANOVA models accounted for relatively little variation, indicating that other factors may contribute to tree diversity in parkland systems. The most threatened species were Adansonia digitata, Afzelia africana, Bombax costatum, Celtis integrifolia, Ficus asperifolia, Ficus iteophylla, Lannea velutina, and Parkia biglobosa. These species were represented in the largest diameter class (≥80 cm) or showed very few individuals in the different diameter classes. Due to the increasing degradation of the parklands, a domestication and conservation strategy of key threatened species needs to be developed and implemented with the participation of local communities. [ABSTRACT FROM AUTHOR]

Vitellaria paradoxa , the shea tree, an economically important fruit-tree species native to savanna regions is threatened in Burkina Faso due to overexploitation and changing land-use. Furthermore, it remains unclear how climate change will influence its frequency and distribution. We investigated the impact of climate change on the projected spatial distribution of favorable habitats for V. paradoxa. Species distribution modeling techniques implemented in MaxEnt combined with GIS were used to forecast the current and future distribution of V. paradoxa. We selected two climatic scenarios (RCP4.5 and RCP8.5) and two global climate models (MPI-ESM-MR and HadGEM2-ES) to encompass the full range of variation in the models. Presence records of the species were collected and linked to bioclimatic and edaphic variables. The most characteristic and least correlated variables were selected for modeling after a collinearity test. Under current climatic conditions, ~51% of the national area was found to be favorable for cultivation and conservation of the species. Under future climate projections, our models predict that favorable habitats of this species will decline by 12% (RCP4.5) and 13% (RCP8.5) by 2070. The predictive modeling approach presented here may be applied to other economically important tree species. • Vitellaria paradoxa is a multipurpose, and agroforestry tree species in West Africa. • Species occurrence records were combined with climatic and soil data in MaxEnt. • We used the IPCC's RCP4.5 & RCP8.5 emission scenario for 2050 & 2070 for our modeling. • Suitable habitats for Vitellaria paradoxa likely to decrease by up to 13.25%. • Results could be used as basis in formulating appropriate adaptation policies. [ABSTRACT FROM AUTHOR]