Parkland Trees Research Articles

Assessment of Parkland Tree Species and Their Management Practice in Ana Sora District of Guji Zone, Southern Ethiopia

The study was conducted to identify parkland tree species and their management practice by smallholder farmers in Ana Sora District of Guji Zone, Southern Ethiopia. The study was conducted by using multistage sampling methods. In the first stage one district was purposively selected based on the potential of park land tree species. Then, from the district by using simple random sampling methods two kebeles were selected and purposively from 40 farm lands an assessment of parkland tree species were conducted. In this study, 31(thirty one) tree species were identified in parklands of the study area and majority of them were indigenous tree species. In terms of parkland tree species preferences, Schefflera abyssinica, Hagenia abyssinica, Millettia ferruginea, Cordia africana and Croton macrostachyus were the most preferred top five tree species of the study area respectively. This study also showed that, farmers practiced thinning, pruning and pollarding management activities for better growth of underneath crops, to transfer the biomass of the trees to the crop fields and for various products of the trees. Moreover, smallholder farmers of the study area were obtained different services and products such as bee forages, shade, construction material, soil fertility improvement and fuel wood from parkland tree species either retained or planted on their farm lands. However, parkland tree species of the study area were faced various constraints. Therefore, attention should be given on conservation of parkland tree species and farmers should be encouraged by the government through research and extension services and supplying by planting materials to improve the significant of ecological and productive role of parkland tree species of the study area.

Assessment and Characterization of the Traditional Parkland Agroforestry Practices in Mid and Lowlands of Bale: In the Case of Goro and Ginnir Districts

Agroforestry parklands are playing an important role, through trees and shrubs providing multiple products and important long-term ecological benefits. Purposive sampling methods were applied to select districts, PAs and farmers which mostly used parkland agroforestry practices. Based on information delivered from informal assessment result, formal survey was done with selected 84 HHHs (sample size) for the study purposes. Based on the existences of long lived parkland agroforestry practice and associated challenges four PAs from Ginir and Goro districts of Bale Zones were selected purposively with assistance of district agriculture office expertise and DAs. Survey results showed the presence of 17 woody species of trees and shrubs representing eleven (11) families at the study areas. Of seventeen (17) woody plant species retained/planted and managed on parklands, 82.4% were native. Fabaceae was the most dominant woody species family which accounted about 41.2% of the total number of species recorded. The Croton macrostachyus Hochst., Faidherbia albida, Cordia africana Lam., Acacia abyssinica Hochst., Junperus procera Hochst and Acacia species were the most frequently observed multipurpose woody species in the study area. Almost all of the respondents did practise different types of management activities or practices for the woody species they owned in parkland of the study areas. This finding revealed that pollarding (33.45%), coppicing (21.08%), branch pruning (35.56) and the rest thinning and protection woody species management practices were applied to the scattered trees on croplands of the study areas. On other side, respondents stated that the major challenges for the improvement of parkland agroforestry practices in the study area were instability of rain fail or drought (34.52%) and shortage of farmlands (21.43%). The finding of this study showed that agricultural landscapes (Parkland agroforestery practices) were the home/host of reasonable number of native woody species flora conservation or it’s almost the remnants of the natural vegetation. Therefore, further need for more comprehensive analysis of the multiple benefits and services provided by parkland trees located on farmlands or the interaction effects of the agroforestery components on soil fertility improvement, crop yields and quality in the future.

Investigation of Woody Species Composition, Diversity, and Carbon Stock under Agroforestry Practices in Oromia National Region State, Central Ethiopia

Agroforestry is a common practice in the tropics that is characterized by various activities such as parkland on cultivated lands or home garden agroforestry around homesteads. In Ethiopia, agroforestry is an ancient land use type that is practiced by smallholder farmers. Scattered trees in cropland or parkland trees and home garden trees are old agroforestry practices, and the most dominant practices exist in different parts of Ethiopia. They cover large areas of highland, midland, and lowland agroecologies of Liban Jawi District in West Showa of Oromia National Regional State, Central Ethiopia. However, woody species particularly in parklands are declining in many agricultural landscapes due to the overuses for fuel wood, charcoal production, and expansion of agricultural lands due to the degradation of nearby forests. In the study sites, comprehensive studies in terms of their composition, diversity, structure, and carbon stocks are still not well explored. In this context, we assessed woody species composition and diversity, structure, and carbon stocks because parkland and home garden agroforestry practices in three agroecologies of highland, midland, and lowlands in the district were not quantified. About 45 parkland woody species were collected from 150 plots of 5000 m2, and 35 home garden woody species were collected from 70 plots of 400 m2. As a result, a total of 80 species belonging to 52 families and 62 genera were collected from parkland and home garden agroforestry practices. Woody species diversity was analyzed using species richness, Shannon diversity index, and Shannon evenness index. In this study, the Shannon diversity (2.8) and Shannon evenness indexes (0.54) of woody species were computed in parkland agroforestry, in the meantime the Shannon diversity index (3.30) and Shannon evenness index (0.52) for woody species of the home garden were computed. The distribution of diameter classes of 10–30 cm had the highest number of trees and shrubs followed by 31–60 cm diameter classes. However, the highest number of trees and shrubs were in 61–90 cm diameter class in the home garden. In this study, woody species, such as Citrus sinensis, Mangifera indica, Persea americana, Sesbania sesban, Vernonia amygdalina, and Azadirachta indica were the dominant species under the two agroforestry practices. The values of carbon stack for highland, midland, and lowland in parkland agroforestry were 19.8 MgCha−1, 17.6 MgCha−1, and 17.5 MgCha−1, respectively. Meanwhile, the total biomass of woody species in highland, midland, and lowland for homestead agroforestry was 32.6 MgCha−1, 34.7 MgCha−1, and 31.2 MgCha−1, respectively. These resulted in carbon dioxide sequestered of 72.59 CO2 equivalents (tha−1), 64.52 CO2 equivalents (tha−1), and 64.16 CO2 equivalents (tha−1) in highland, midland, and lowland woody species, respectively. This study holds significant inputs for policymakers, regional administrators, environmentalists, and natural resource experts by informing the farmers’ management and conservation of woody species on cultivated lands and home garden agroforestry plants around their homesteads which is serving as ecosystem services and climate mitigation response within Liban Jawi district. Under parkland and homestead agroforestry practices, communities should have know-how to predict the environmental consequences of the destruction of woody species on their farmlands.

The agroforestry-biodiversity-climate change nexus

Amongst human activity, industrial agriculture is a primary cause of biodiversity loss and climate change, reducing the land’s suitability for agriculture. This reduces global food security, increasing the pressure for food production which further exacerbates forest and land degradation. Agroforestry emerges as a promising solution by leveraging nature-based approaches to mimic natural ecosystems, combining trees with annual crops, to tackle both biodiversity loss and climate change. The adoption of tropical agroforests, shade-tolerant crops, scattered trees in parklands and homestead agroforestry, are all examples of how agroforestry has helped promote diverse and resilient landscapes capable of adapting to changing climatic conditions, while still providing essential ecosystem services. The positive influence of agroforestry on ecological processes is further supported by scientific evidence which shows that agroforestry enhances soil health, serves as a carbon sink and promotes resilience against climate hazards. The adoption of agroforestry may be hindered, however, by knowledge gaps, policy recognition and variations in effectiveness across different contexts. These can and should be overcome, because agroforestry is recognised by international organisations as a key strategy in sustainable land management and climate change mitigation, and as a vital tool for addressing food security on a global scale.

Parkland trees on smallholder farms ameliorate soil physical-chemical properties in the semi-arid area of Tigray, Ethiopia

Parkland trees on smallholder farms ameliorate soil physical-chemical properties in the semi-arid area of Tigray, Ethiopia

Calibrating the STICS soil-crop model to explore the impact of agroforestry parklands on millet growth

ContextAgroforestry systems provide critical benefits for food security and climate change mitigation. Yet, they are complex and heteregoneous sytems hard to optimize. The use of process-based crop models provides an opportunity to understand better the interactions between soil, crop, tree and climate and explore the impact of agroforestry on crop growth, for contrasting crop management. ObjectiveThe objectives of this study were to i) calibrate the soil-crop STICS model for pearl millet (Pennisetum glaucum) in order to simulate millet potential growth and impact of water and nitrogen limitations on millet growth in open fields and ii) explore the impacts of the parkland tree Faidherbia albida on millet performance for contrasting N fertilizer inputs. MethodsWe gathered a comprehensive database of 28 agronomically contrasting situations, ranging from near-potential growth to drought- and N-stress, either on-station or in a farmer’s home- or bush-fields. Parameters governing relevant plant and soil processes for grain yield were calibrated in a stepwise procedure. The calibrated model was used to explore the impact on millet growth of the widely reported benefits of Faidherbia albida, namely a minimum reduction in radiation thanks to the peculiar reverse phenology of this tree, improvement of soil water content at the beginning of the growing season and of organic nitrogen in the topsoil. ResultsModel simulations with the calibration dataset were reasonably accurate for aboveground biomass and grain yield. Normalized Root Mean Square Errors (nRMSE) for these variables were 29% and 26%, respectively; model efficiency (EF) was 0.58 for both. The nRMSE ranged from 33% to 53% for Soil Water Content (SWC), plant N uptake, grain number, and leaf-area index (LAI). Model accuracy was lower with the evaluation dataset. In the virtual experiment, millet yield decreased with incoming solar radiation, but only at levels of shading (e.g. below 80% of the radiation obtained with full sun) that do not occur under Faidherbia. The decline was greater when millet was fertilized. Increasing the initial soil water content did not affect simulated millet growth. Simulated millet aboveground biomass and grain yield increased with higher organic nitrogen contents of the topsoil, by 80% when millet was not fertilizer, but only by 25% when millet was fertilized. ImplicationsThis study provides the first set of comprehensively calibrated parameters for applying STICS to pearl millet in open cropland. A virtual experiment with historical climate suggests that the benefits of Faidherbia decrease if farmers intensify crop production by adding more mineral N fertilizer. Hence, precise fertilizer management is recommended in Faidherbia parklands. These results illustrate the benefits of process-based crop modelling for better understanding the functioning of agroforestry systems.

A Novel Approach to Match Individual Trees between Aerial Photographs and Airborne LiDAR Data

Integrating multimodal remote sensing data can optimize the mapping accuracy of individual trees. Yet, one issue that is not trivial but generally overlooked in previous studies is the spatial mismatch of individual trees between remote sensing datasets, especially in different imaging modalities. These offset errors between the same tree on different data that have been geometrically corrected can lead to substantial inaccuracies in applications. In this study, we propose a novel approach to match individual trees between aerial photographs and airborne LiDAR data. To achieve this, we first leveraged the maximum overlap of the tree crowns in a local area to determine the correct and the optimal offset vector, and then used the offset vector to rectify the mismatch on individual tree positions. Finally, we compared our proposed approach with a commonly used automatic image registration method. We used pairing rate (the percentage of correctly paired trees) and matching accuracy (the degree of overlap between the correctly paired trees) to measure the effectiveness of results. We evaluated the performance of our approach across six typical landscapes, including broadleaved forest, coniferous forest, mixed forest, roadside trees, garden trees, and parkland trees. Compared to the conventional method, the average pairing rate of individual trees for all six landscapes increased from 91.13% to 100.00% (p = 0.045, t-test), and the average matching accuracy increased from 0.692 ± 0.175 (standard deviation) to 0.861 ± 0.152 (p = 0.017, t-test). Our study demonstrates that the proposed tree-oriented matching approach significantly improves the registration accuracy of individual trees between aerial photographs and airborne LiDAR data.

Exploring the landscape scale influences of tree cover on crop yield in an agroforestry parkland using satellite data and spatial statistics

Trees in agroforestry parklands influence crops both through competitive and facilitative mechanism, but the effects are challenging to disentangle due to the complexity of the system with high variability in tree cover structure and species diversity and crop combinations. Focusing on a landscape in central Burkina Faso dominated by Vitellaria paradoxa and Parkia biglobosa, this paper examines how tree cover influences crop yield at landscape scale using satellite data and spatial statistics. Our analysis is based on data from 2017 to 2018 with differences in rainfall to assess the stability in identified relationships. Our findings showed that tree canopy cover and tree density inside the fields tended to decrease crop yield because of competition, but also that these variables when considering the surrounding landscape exerted an opposite effect because of their buffering effects. The explanatory variables representing soil properties did have limited effects on crop yield in this study. These patterns were consistent during the two years of monitoring. Overall, our results suggest that farmers in this area might manage the tree cover in a way that optimizes sustainable yields as canopy cover and tree density in most parklands is below the limits identified here where competition outweight the facilitative effects.

Climate-growth relationships of Daniellia oliveri (Rolfe) Hutch. & Dalziel in the Sudanian zone of Mali, West Africa

Tree rings depend on seasonal variation in radial tree growth. Where they can be identified, their interannual variation may reflect climate variability. Compared to its use in temperate and boreal regions, tree-ring analysis has been less applied in tropical Africa, with weaker seasonality. Daniellia oliveri often forms the tallest trees in agroforestry parklands of the Sudanian savanna zone of Mali but its growth response to climate (rainfall, temperature) variability has not been documented. We analyzed six stem disks of D. oliveri and used standard dendrochronological methods to process the samples. Contrary to earlier literature likely based on more humid parts of the species distribution range, D. oliveri formed distinct growth ring boundaries in our study area. The mean annual radial growth was 2.73 ± 0.56 mm. All measured tree-ring series were successfully cross-dated with a GLK (Gleichläufigkeit) value of 76.3 ± 5.6. The final tree-ring chronology covers the period 1909-2021. After removing age-related growth trends, the tree-ring width index showed a significant relationship with records of annual rainfall (r2 = 0.46, n = 100 years, p < 0.001). The relationship between wet-season (June to September) precipitation and the residual chronology was slightly higher (r2 = 0.50, n = 100 years, p < 0.001). However, no significant correlation was found for temperature. These results imply that D. oliveri can be successfully used for dendrochronological studies with relevance for the management and restoration of the ecosystems in the Sudanian zone of West Africa, where long-term rainfall records are scarce.

Floristic composition of agroforestry parklands in the semi-arid zone of Ghana: A special focus on Faidherbia albida (Delile) A. Chev

In order to understand the dynamics of regeneration, growth, population and possible upscale for the benefit of agroforestry parkland trees in the semi-arid areas of Ghana, a study was conducted to determine the population density, diversity, relative dominance, importance value indices (IVI) and use categories of parkland tree species in the Sudan and Guinea Savannah vegetation zones of Ghana, with special reference to F. albida. Tree inventories were conducted on 80 sampled farms covering a total area of 74.2 hectares across 8 communities distributed in 4 districts in the Sudan and Guinea savannah zones. Mean farm size was 0.93 hectares. Fifty-four tree species belonging to 24 families were encountered during the study. A Simpson's diversity index of 2.72 was determined as the overall diversity index of tree species on farmlands. Tree population densities in the sampled communities ranged between 4 (Katiu) and 11 (Kugri) trees per hectare. The predominant uses of parkland trees include food, medicine, shade, fuelwood and wood for construction. Others include fencing, soil improvement, direct income from sale of tree products, erosion control, fodder, tools, deity, packaging and craft. Ranking parkland tree species according to their Importance Value Indices (IVIs) in the various study ecological zones, it was evident that Faidherbia albida is highly ranked in both ecological zones due to its multipurpose functions such as fodder (pods and leaves) provision, shade provision in the dry season, and its contribution to improved growth and yield of crops grown under its canopy. Faidherbia albida populations should be increased on farmlands through programs like the Farmer Managed Natural Regeneration (FMNR) and possible domestication.

Parkland Trees under Severe Drought: An Assessment of Species Diversity and Abundance across Three Agroecological Zones of Northern Nigeria

The appraisal of tree stand structure on parklands is crucial for sustainable agroforestry management decisions, particularly in the drylands of Nigeria. An assessment of tree species distribution in farm plots across the three driest Agroecological zones (AEZ) within Northern Nigeria was performed to determine diversity and abundance in a changing climate. The AEZ include Sudan savannah (SS), Northern Guinea savannah (NGS) and Southern Guinea savannah (SGS). In each AEZ, 3 transects were laid per village and a total of 4 sample plots were located along each transect. Tree bole diameter of all the sampled woody perennials with dbh ≥ 10 cm was measured and identified to species level. The measurement and computation include basal area, species relative density and dominance as well as the important value index (IVI). Results showed that across the AEZs, Parkia biglobosa trees had the highest IVI but reduces from the driest zone, SS (50.25%) through the transitional zone, NGS (38.45%) to the wettest AEZ, the SGS (35.43%). The lowest IVI recorded were in Gliricidia sepium (0.62%), Psidium guajava (2.89%) and Eucalyptus camaldulensis (1.83) in the SGS, NGS and SGS respectively. Parkia biglobosa and Mangifera indica dominated the landscapes and are classified as the landscapes’ habitat generalists. Despite the low organic matter content, Sudan savannah had more diverse species on its farm landscapes than the two other AEZ but with less tree popuplation density. The potential contribution of agroforestry parkland trees to agrobiodiversity in reducing drought and improving soil fertility is essential for sustainable agricultural productivity and landscape restoration.

Management and Environmental Contribution of Woody Species Diversity Parkland Agroforestry System in Ethiopia

Parkland agroforestry practices have placed greater emphasis on improving the climate, improving fertility, protecting water, and improving biodiversity. The objective of this paper is therefore to review the management and its ecological contribution to the diversity of wood species in agroforestry in Ethiopia in parklands. The practice is known by growing isolated trees on arable land by incorporating annual plants; that preserves biodiversity. Parkland agroforestry, a system practiced by many local populations, encompasses most of the agricultural landscape in Ethiopia and is very important in several aspects such as: for food security, microclimate improvement, economic benefits, environmental protection, household energy, household appliances, cultural values, traditional medicine and animal feed. There are many indigenous multipurpose tree species scattered across farmland in Ethiopia, and some of the most popular include: Millettia ferruginea, Cordia africana, Ficus vasta, Ficus sur, Croton macrostachyus, and Faidherbia albida. Parkland tree management is a process for controlling arboriculture competition in agricultural fields, so the selection and management of the species involved affects the success of the system. Management of the trees is essential to ensure the continued return of mulch or leaf forage and light shade through the use of heading, pruning and pruning measures, which should be done in early summer.

Contribution of parkland agroforestry in supplying fuel wood and its main challenges in Tigray, Northern, Ethiopia

Agroforestry is an aged practice in the Ethiopian farming systems of which parkland trees comprise the large part of agricultural landscapes. It is also the most dominant agroforestry practice in the semi-arid and sub-humid zones of Ethiopia. However, there is lack of research based evidence that shows the contribution of parkland agroforestry on fulfilling households’ fuel wood demand and towards improving the smallholder farmers’ livelihood. Hence, the main objective of this study was to assess the role of parkland agroforestry practice on fulfilling households’ fuel wood demand, improving livelihood and to identify the main constraint. Primary data was collected from actual field measurement and questionnaire based face to face interview with randomly drawn 138 parkland agroforestry user and non-user. Guided field observations, interview with key informants and focused group discussion were also conducted. About 108.56 ton (79.2%) annual fuel wood consumption was harvested from the parkland trees; whereas the non-parkland agroforestry households were mainly dependent on the surrounding natural forests to meet their fuel wood demand. The Propensity Score Matching model result indicated that there was significant difference (p<0.05) among the parkland agroforestry introduced and non-introduced households on the time they spent to collect fuel wood and income. Parkland agroforestry plays a crucial role in the households’ livelihood improvement (for example, income) and also to stabilize the pressure on local forests. However, the major challenges faced to improve the parkland agroforestry practice are farmland distance, free grazing, farmland size, general prohibition of fire wood selling, lack of farmers’ awareness, lack of extension support and dry climatic condition. Therefore, to enhance the multiple benefits of the parkland agroforestry, the main constraints that hinder the sustainability of the parkland agroforestry should be addressed. Key words: Agroforestry, fuel wood, livelihood, household, local forest, parkland.

A global systematic review on conservation nd domestication of Parkia biglobosa (Jacq.) R. Br. ex G. Don, an indigenous fruit tree species in Sub-Sahara African traditional parklands: current knowledge and future directions

Parkia biglobosa (Jacq.) R. Br. ex G. Don is one of the most common traditional parkland tree species that generates vital non-timber forest products and benefits for local people in Sub-Saharan Africa. Despite its socio-economic importance and value for local and regional economies, the species has remained at infant stage of domestication, yet declining in the nature. While several studies addressed various ecological, social and economic aspects, systematic reviews and literature syntheses on current knowledge and research gaps are lacking, despite their relevance for future research directions. Based on research publications from ScienceDirect, Google Scholar and African Journals Online, we provide a systematic literature review of the current knowledge on the ecological, socio-economic, conservation, and domestication aspects of P. biglobosa. We also identified important research gaps and future prospects for the species conservation and domestication. From 2060 publications initially recorded, 221 received full-text assessment after screening, of which 184 scientific papers were finally reviewed. Approximately 75% of these studies were undertaken in three West-African countries: Nigeria, Burkina Faso and Benin. Critical analyses were presented in line with perspectives on ecological, socio-economic, conservation and domestication aspects. The review highlighted the critical research gaps in distributional ecology, tree physiology, plant demography, molecular biology, genomics and evolutionary biology, but also called for more research effort from Central and East Africa, where a limited number of publications was recorded on P. biglobosa, in spite of being within the native distribution range. Such investigations would help in decision-making and elaboration of breeding strategies, as steps towards sustainable use and domestication of the species in Africa.

Contribution of Parkland Agroforestry Practices to the Rural Community Livelihood and Its Management in Southern Ethiopia

Parkland agroforestry which is a system practiced for many local populations is very important for food security, microclimate amelioration, income generation and environmental protection, and is found at different corners of the world, primarily in the semi-arid and sub-humid zones of Africa. It is reported that agroforestry practice is an aged practice in the Ethiopian farming systems of which parkland trees comprise the large part of agricultural landscapes and it is also the most dominant agroforestry practice in the semi-arid and sub-humid zones of Ethiopia. This study was conducted on farmers’ parkland Agroforestry practice in Burka Ebela of Bule Hora District Southern Ethiopia which was purposely selected. The objective of this study was to assess contribution of parkland Agroforestry practices to the rural livelihood community. A total of 90 respondents were selected in a systematic sample way from total households of 888 in the study area based on formula used. The data were analyzed using descriptive statistics. The result obtained from the survey showed that, 11 tree species as parkland tree were identified. From those identified tree species the most preferred trees by farmers are: <i>Accia Abyssinica, Accia Albida, Cordia Africana, Croton Macrostachyus Eucalyptus, FicusVasta, Millettia Ferruginea, Podocarpus Falcatus, Rhamnus Priniode and Ricicus Commonis</i> and community used those trees for different purpose such as; for food security, microclimate amelioration, economic benefits, environmental protection, household energy, household utensils, cultural values, traditional medicines and fodder. Challenge to parkland Agroforestry practice in the study area were the exotic tree expansion, plant diseases transmission from old trees to young trees, small land size and lack of replanting. Moreover, these trees are facing challenges like: expansion of cash crops through removal of the parkland trees from the farm area. Even though common management of parkland agroforestry system on the study area was thinning and prunings, more people do not management parkland tree well.

Impact of &amp;lt;i&amp;gt;Parkland&amp;lt;/i&amp;gt; Trees (&amp;lt;i&amp;gt;Faidherbia albida&amp;lt;/i&amp;gt; Delile and Cordia Africana &amp;lt;i&amp;gt;Lam&amp;lt;/i&amp;gt;) on Selected Soil Properties and Sorghum Yield in Eastern Oromia, Ethiopia

The study was conducted to investigate the impact of Parkland trees in farmland on selected soil physicochemical properties and sorghum grain yields in Fedis District, Oromia, Ethiopia. For the experiment of soil physicochemical properties, three factors: distance from tree trunk with three levels (at 2.5m of crown, edge of crown radius and open field), soil depth with two levels (0-20cm and 20–40cm depth) and tree species with two levels with factorial arrangement in RCBD replicated six times were employed. For sorghum grain yield only two factors; distance from tree trunk with three levels (at at 2.5m of crown, edge of crown radius and open field) and tree species (F. albida and C. africana) with two levels in RCBD replicated six times were used. The result revealed soil texture was not influenced significantly (P>0.05) by tree species. Soil bulk density was significantly (p 0.05) influenced by both tree species. The grain yield of sorghum (sorghum bicolor) were significantly (P<0.05) higher under canopy of both trees species as compared to the open field. In general, the nutrients contents increased by 84.3% and 71.5% for OC, 84.2% and 70.8% for OM, 66% and 59% for SOC Stocks, 82% and 84% for TN, 96% and 79% for AP, 15.6% and 34.2% for CEC, 30% and 10% for EC, 82% and 27.2% for Na, 41% and 30.4% for K, 33.8% and 28.2% for Ca and 58% and 87% for Mg and 13.22% and 13.15% for MC and by 43% and 41% for Sorghum yield were detected under the canopies of F. albida and C. africana tree species respectively. It can be concluded that these tree species have the potential to improve soil fertility and moisture beneath its canopy. Thus, retaining these tree species and in particular F. albida on crop field in the study area is of paramount importance for soil fertility enhancement so as to improve food security of small farming households.

Parkland Agroforestry of Ethiopia; Key to Production, Productivity, Biodiversity Conservation and Climate Change Mitigation: A Review

Compiled information on parkland agroforestry tree species in relation to diversity, tree management options and the challenges of the system is important for production and productivity, and biodiversity conservation through availing the required information which in turn has an implication to the sustainability of the system and climate change mitigation. So, the aim of this review paper is to compile information on parkland agroforestry practices of Ethiopia, particularly: on tree species diversity, their roles, management options available and challenges of the practice. Parkland agroforestry which is a system practiced by many local populations comprises the large part of agricultural landscapes in Ethiopia and is very important in different aspects such as; for food security, microclimate amelioration, economic benefits, environmental protection, household energy, household utensils, cultural values, traditional medicines, and fodder. There are many indigenous multipurpose tree species scattered on farmlands in Ethiopia, and the common one includes: Millettia ferruginea, Cordia africana, Ficus vasta, Ficus sur, Croton macrostachyus and Faidherbia albida. However, nowadays these trees are facing challenges like: expansion of exotic trees in the expense of the native ones, expansion of cash crops through removal of the parkland trees from the farm area, climate change, land shortage and tenure system which require high emphasis for the production and productivity as well as sustainability of the system especially, in this era of climate change; hence this system is one of climate change mitigation options.

Controlled pollinations reveal self-incompatibility and inbreeding depression in the nutritionally important parkland tree, &lt;i&gt;Parkia biglobosa&lt;/i&gt;, in Burkina Faso

The socioeconomically important fruit tree Parkia biglobosa is becoming less abundant in the West African savannah, possibly due to poor regeneration. This decline can be self-enforcing if lower densities of fertile trees result in increasing self-pollination followed by increased abortion rates or poor regeneration due to inbreeding depression. Hence, we have studied the reproductive success and seedling viability of P. biglobosa after controlled self- and cross-pollination based on a full diallel crossing design with eight trees. Controlled cross-pollination tripled the pod set compared to open-pollinated capitula, suggesting that fruiting of P. biglobosa trees in the study area is already seriously pollen limited. Self-pollination and specific pairs of trees resulted in very few pods, suggesting a high level of self-incompatibility. Cross-pollination resulted in larger pods with more and heavier seeds than self-pollinated pods. The total amount of sugar in the fruit pulp was correlated with both the number of healthy and total seeds per pod. Growth rate of self-pollinated seedlings was lower than the cross-pollinated ones, suggesting significant inbreeding depression. Because the wild fruit trees play an important role in human nutrition, these results give rise to serious concerns. We recommend that future studies investigate how the level of cross-pollination can be increased and how the regeneration of P. biglobosa, whether natural or planted, can be improved.

Woody Species Diversity of Parkland Agroforestry in Ethiopia

Parkland agroforestry system has a crucial role in social, economic and environmental value. For instance, woody tree in Parkland improve soil fertility and enhancing crop productivity. Parkland tree have a potential of AM colonization and increase soil moisture to facilitate microbial activity. Park land agroforestry is a system where farm crops are mixed with trees to supply fodder, fuel, leaf litter, medicinal herbs, fruit, timber, etc. Predictably, the farmers have only grown a single crop on one field. Also, there is a belief that crops cannot grow well in the shade of nearby trees, so trees will often be cleared from cropland. In the days when there was plenty of forest near to the village, there was no shortage of fuel, fodder, etc. But now, overcutting of fodder, firewood, timber, etc., and grazing livestock, has destroyed the forests. So farm yields have become lower and lower. More landslides have been an extra problem. By planting parkland land agroforestry, farm needs for fodder, timber, fuel, etc. can be met as well as protecting the environment.

Honey bees ensure the pollination of &lt;i&gt;Parkia biglobosa&lt;/i&gt; in absence of bats

One of the socio-economically important West African parkland trees, Parkia biglobosa yields pods consumed by people and animals. Being animal-pollinated, it is unknown how climate change will affect the species if the guild of pollinators changes. Here, we compare the pollinator guilds and the pod production at two climatically different study sites: the first site, Tiba was drier with lower tree density and fewer fruit bats, whereas the second site, Pinyiri was more humid, with higher tree density and more fruit bats. We carried out a pollinator exclusion trial with bags separating the flower-visitors and made observations of the flower-visitors. Furthermore, we calculated pollination distances based on paternity analysis of the seeds produced within the trial. The numbers of immature fruits were similar for the sites, but the drier site, Tiba experienced more abortion and decreased pod set. At both sites, exclusion of bats led to marginally reduced pod set, while exclusion of bats and honey bees led to significantly reduced pod set. We found a small effect of stingless bees and solitary bees but only at the more humid site, Pinyiri. Tiba experienced a higher level of self-pollination, fewer pollen donors per tree, and longer median distances of pollen flow, compared with Pinyiri. Implications of the results for management of the species and its pollinators in the face of climate change are discussed.