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Background Aim: Land use change causes a remarkable change in soil properties. The nature of change depends on multiple factors such as soil type, type and intensity of land use, climate, and the like. This study investigated the variation in soil physicochemical properties across five common land use practices i.e., enset system, farmland, and grazing-land (closed and open), and Eucalyptus woodlots practiced on originally same soil type and comparable topographic and climatic settings.Methods: A total of 105 disturbed and undisturbed soil samples [5 treatments (land use types) *7 replications (household)* 3 soil depth layers: 0–15cm, 15–30 cm, 30–45cm] were collected for selected soil chemical and physical analyses. Standard soil analytical procedures were followed in carrying out soil analysis. To meet the assumptions of normal distribution and homogeneity of variances, soil data on available phosphors were log-transformed before statistical analysis was undertaken and reported after back transformation. Two way analysis of variable were used to investigate the effects of land use and soil depth and their interaction on soil properties and when the analysis showed a significant difference (p Results: There were significant differences in physical and chemical properties of soil across land use and soil depth categories. Enset system had significantly higher pH, available phosphorus (P), exchangeable potassium (K+), soil organic carbon (SOC), and total nitrogen (TN) and their stocks than other land use types. Enset fields had higher SOC (78.4%) and soil TN (75%), and SOC and TN stocks of (66%) and (58%), respectively than cereal farmland. This study had also revealed a less expected finding of higher soil organic carbon and total nitrogen under Eucalyptus wood than farm land. Soil carbon and total nitrogen stocks showed a decreasing trend of enset system> closed grazing-land > eucalyptus woodlot > open grazing-land > farmland 0-45cm.Conclusion: Overall, some land use systems (e. g. enset agroforestry) improve the soil biophysical and chemical properties, while others such as cereal production degrade the soil. Hence appropriate land and soil management intervention should be promptly adapted to mitigating the continuous loss of nutrient from the dominantly practiced cereal farm land through maintaining crop residues, manure, crop rotation and scaling up agro-forestry system.

Background and Aims Biomass carbon (C) stocks of trees across three common traditional agroforestry practices (i.e. home-garden, farmland, and grazing land) and along altitudinal gradients (i.e. upper, middle and lower) in southern Ethiopia are presented and evaluated. These traditional AF systems are characterized by a high proportion and diversity of trees hence can play a remarkable role in climate change adaptation and mitigation.Methods Data were collected from a total of 89 plots: 41 home-gardens, 29 croplands, and 19 grazing lands using total count and Y-frame transect sampling methods. Above- and belowground biomass of trees were calculated using allometric equations developed somewhere else but proven for application in agroforestry systems. Trees with DBH ≥ 2 cm were considered for biomass carbon stock determination.Results above-ground biomass carbon stock of the three land uses showed the order: Home-garden > grazing land > cropland, but the differences in the carbon stocks were not statistically significant. Soil carbon stocks measured from the studied land uses at middle altitude also followed a similar trend. Similarly, differences among altitudinal gradients were not statistically significant. However, the variations observed reflected differences in species composition among the system as well as altitudinal gradients. Other factors such as wealth and garden size also significantly affected biomass C stocks per ha, where rich household holds higher above-ground biomass than medium and poor households. Overall, this reflects that rich households own a large parcel and large total number of trees, compared to that of medium and poor wealth classes.Conclusions The biomass C stocks of the tree across the three studied AF systems were found to be lower than reported for tropical forests and agro-forestry systems due to the recently agro-forestry intensification in the form of reduction in tree diversity and density. For enhancing their biomass carbon stocks traditional agro-forestry should be integrated in future REDD+ projects. As the biomass C stocks were more determined by socioeconomic factors such as wealth and garden size than the types of agro-forestry practice and climate (elevation) future carbon management strategies should also considered them.

Whereas some conservationists argue that ‘people-oriented approaches’ failed to achieve conservation goals, Nechisar National Park presents a case where ‘strict conservation approaches’ have at best been only partly successful. Nechisar National Park, heralded as a success in the 1990s, today shows a collapsed population of the endemic Swayne’s hartebeest and severe degradation of the emblematic grasslands of the plains. The park is also heavily under pressure from firewood collectors and fish stocks have plummeted. Drawing on the concepts of ‘indirect’ and ‘direct’ costs/benefits of conservation areas – as proposed by Richard Bell – we wanted to get beyond the ‘strict’ versus ‘people-oriented’ conservation debate. Based on semi-structured interviews (12 women, 4 men) and oral testimonies (19 women, 17 men) we analyse how access to natural resources evolved under different political regimes and conservation strategies. The strict conservation approach resulted in strong opposition against the park...

Key messages The highland mixed farming system found in mountainous areas of north-west, north-east and southern Africa is heavily constrained by land degradation, high population density, small landholdings, poor infrastructure, limited market opportunities and limited community capacity to respond to external shocks. The system produces special mountain products, including wool, herbs, medicinal plants, highland fruits, organic products, in addition to basic food grains, meat and milk. There is strong interdependency between crops and livestock in terms of draught power, nutrient cycling, food security and ecosystem management. With climate change and increased temperature, the system and the associated water towers would become more fragile, with reduced water yield, recurrent drought and extreme events. There is a need for collective action for coordinated management of upstream and downstream systems for mutual benefit. Investment is required to enhance productivity to feed the growing population while maintaining/improving the ecosystem services. Targeted support is needed for system integration and resilience, including policies and strategies to add value and link mountain produce with niche markets, thereby facilitating positive livelihood change.

Ethiopia has made an ambitious pledge for Forest Landscape Restoration (FLR) under the Bonn challenge and the so-called AFR100 initiative – to restore 15 Mio ha of degraded forest lands by 2030. This target is in line with national and international policy objectives to effectively address climate change and develop a ‘Climate Resilient Green Economy’. Implementation at scale is pending as technical, financial and policy challenges need to be addressed. This paper presents a case study that was commissioned by German technical development cooperation. The objective was to develop a landscape restoration strategy for the area connecting Chebera Churchura national park and Kafa Biosphere Reserve in the Southwestern part of Ethiopia. The ‘Restoration Diagnostic’ tool developed by the World Research Institute was used to identify options for establishing a biodiversity corridor and to assess FLR opportunities. Based on the results of a field study and extensive GIS analysis, suitable FLR measures were identified and discussed in stakeholder consultations. Results show that more than 25% of the entire area is suitable for restoration measures; however, in the populated parts of the landscape a focus on productive aspects seems critical, i.e. to improve the provision of food, fuel wood and timber. Barriers relate to low institutional capacity, lack of infrastructure and undeveloped forest product value chains. Addressing these challenges can significantly contribute to sustainable management of natural forests in the buffer zone of the protected areas, and to promote agriculture and socio-economic development of the zones outside protected areas. The findings of such assessments can inform decision makers and donor organizations about FLR in candidate areas. If they become a key source of information in the respective policy processes they can contribute to effective governance of FLR.

Land use/land cover change drive changes in several ecosystem processes over short and long terms. In Ethiopia, the main land use/land cover change involves conversion of natural ecosystem into cultivated land. However, a recent change also involves conversion of cultivated and grazing land into Eucalyptus woodlots. This study was conducted to analyse the effects of such land use/land cover change on soil and nutrient losses. Three land use/ land cover types (cultivated land, grassland and Eucalyptus woodlot) were selected for a comparative assessment. A total of twelve runoff plots, each with 43.3 m2 area and with four replications, were installed. Rainfall depth, runoff volume and sediment samples (500 ml) were collected from each plots every morning and evening for 91 days (from 4th July to 2nd October, 2015) in the main rainy season. The sediment samples for ten consecutive days were stored in separate containers and composite sediment concentration samples were weighed after being filtered and oven dried for 24 hours at 105oc. From the samples taken at the end of the rainy season, separate composite a sample before filtration of one litre was analysed in the laboratory for nutrient losses. The effect of land use/land cover on soil and nutrients losses was statistically tested using analysis of variance. The study found that soil loss significantly differed between the land use/land cover types. Soil loss from cultivated land (16.8 ton/ha) was significantly higher than loss from grassland (7 ton/ha) and Eucalyptus stand (8.1 ton/ha). The soil and nutrient losses were positively correlated with runoff volume. There was higher nutrient (N and P) loss from cultivated land than grassland and Eucalyptus. From the results, it can be concluded that soil and nutrients losses are above tolerable limit, and perennial land covers including Eucalyptus stand reduce soil and nutrient losses significantly. This re-affirms the multi-purpose nature of Eucalyptus not only for socioeconomic benefit but also for soil erosion control when planted in appropriate locations. Key words: Cultivated land, grassland, runoff, sediment concentration, runoff plot.

Forests in the highlands of Ethiopia have declined considerably, and the supply of forest-based ecosystem services is eroding. Managing agricultural landscapes as well as enhancing plant biodiversity in agro-ecosystems is and will continue to be one possible strategy to preserve biodiversity, ensure an ecosystem service supply and sustain agricultural productivity. This study investigated the current status and prospects of plant diversity and its determinants in an agricultural landscape dominated by smallholder farmers in Southern Ethiopia. Specifically, the study investigated effects of land use, altitudinal gradient, wealth status and household attributes on plant diversity in agricultural landscapes. A complete count, Y-frame transect sampling method and household interviews were used for the study involving 39 households and 115 sample plots. A total of 166 plant species belonging to 134 genera and 56 families were recorded in all land use types. Of these, 101 were woody plant species (51 trees and 50 shrubs), while 65 were cultivated herbs and grasses. Land use, altitude and household wealth status significantly influenced tree and shrub species richness. Among land uses, home gardens hosted the highest number of tree and shrub species. Upper altitudes and rich households also had the highest tree and shrub species richness compared to others. Plant diversity indices (Shannon, Simpson and Margalef) were affected by altitude, wealth status and land use types. Household location, wealth status, the household attributes of landholding and family size had strong and positive influences on the tree species diversity and woody stem density of households, while educational background and off-farm income were negatively related with household-owned tree stem density. Species preference ranking, seedling demand and importance value index computations indicated the dominance of exotic tree species, which may suggest their economic importance over indigenous tree species. In the long term, this might lead to dominance of exotic tree species in the landscapes, which could cause a potential future threat to the remnant indigenous plant diversity that is currently finding refuge in the agricultural landscapes.

Decline in farmland soil fertility due to nutrient depletion is a concern for smallholder farmers in the highlands of Ethiopia. In this study we tested if long-term addition of compost, either alone or in combination with nitrogen (N) and phosphorous (P) fertilizer, affected available soil nutrient status, grain/tuber harvests, agronomic N use efficiency, and plot level N and P nutrient balances. The on-farm experiments were conducted on four farm fields for up to 6 years in Beseku, Ethiopia. A randomized complete block design was used, with four treatments: full dose of compost applied alone at 2.4 t ha−1 DW organic matter (C); full dose of fertilizer (F); half compost and half fertilizer (CF); and, unfertilized control. In the upper 10 cm of the surface soil, several Mehlich-3 extractable nutrients (B, Ca, K, Mg, P, S, and Zn) had significantly higher concentrations in the C treatment (P

Ethiopia has experienced a long-term deforestation with broad implications for human life and economic activities, but conventional frameworks of economic accounting are not able to assess the country's economic and environmental sustainability in the face of such deforestation problem. In this study, we attempt an economic accounting of Ethiopian forests based on a welfare-economic framework, which assesses changes in the value of forests as natural capital. Our estimates suggest that the recent government re-greening efforts are yet to increase forest assets in the value term, although they have expanded the land areas covered by trees in the country.

Soil fertility decline due to low nutrient input is a constraint for sustainable agriculture in smallholder farming systems in Ethiopia. In this study, crop productivity and soil organic matter buildup were compared in soils receiving locally made compost, applied either alone or in combination with NP fertilizer. The experiments had four treatments: full dose of compost (C), full dose of fertilizer (F), half compost and half fertilizer (CF), and unfertilized control (control). The full dose of compost was equivalent to 2.4 t ha −1 organic matter. The field study was conducted on four farm fields in the village Beseku, each representing different sub-villages. Participating farmers were selected based on their willingness and an assessment of dedication to carry out the experiment. The experiments, a randomized complete block design with three replications, were replicated across four farm fields. The treatments were repeated for six cropping seasons (years), and data on soil nutrient status and crop (maize, wheat, potato, and faba bean) harvests were collected. In the 0–10 cm soil layer, pH was ( P P −1 in C treatment, and by 4.74 and 0.45 t ha −1 in CF treatment. Treatment effects on crop harvests were significant ( P F > C > control in the initial season, CF > C > F > control in the next three consecutive seasons, and C > CF > F > control in the final year of the experiment. The overall combined yield was in the order of CF > C > F > control for maize and faba bean, CF > F > C > control for potato, and F > CF > C > control for wheat. The addition of either compost alone or in combination with NP fertilizer improved soil properties and crop productivity, compared with control and only fertilizer addition. Therefore, compost addition can serve as a complement to fertilizer use and reduce dependence on mineral fertilizer in low-input crop production system. The apparent synergy between compost and fertilizer addition needs further research in order to be explained.

South Omo Administrative Zone in Ethiopia is home to 18 indigenous ethnic groups whose livelihood is vulnerable due to recurrent drought and degradation. Despite the preliminary observation showing the rich dry-forest resource base that, if sustainably managed could enhance livelihoods and biodiversity conservation, there is lack of empirical data on its current status. We conducted a study aiming at quantifying the population status of gum- and resin-bearing species in two randomly selected districts, Hamer and Bena-Tsemay. Seventy-five quadrats (35 at Hamer and 40 at Bena-Tsemay) each measuring 400 m2 were established along line transects to assess species diversity and equitability, density, frequency, dominance, importance value and population structure. We recorded a total of 27 woody species of 12 families and 14 genera. Fifteen species (9 at Hamer and 14 at Bena-Tsemay) of the genera Acacia, Boswellia, Commiphora and Sterculia, were identified as either major sources of commercial gums and resins or their adulterants. Gum- and resin-bearing species comprised 56% and 57% of species richness, 48% and 50% of total density per ha, 95% and 98% of basal area, and 64% and 56% of importance values at Hamer and Bena-Tsemay, respectively. Diversity of the entire woody species assemblage and of the gum- and resin-bearing species was slightly higher at Bena-Tsemay (H= 2.61, 1.4) than at Hamer (H′= 2.48, 1.28), respectively. The diversity and abundance of the resource base suggest potential for development of value-added commercialization of gum and resins to enhance livelihoods and encourage sustainable management of the forest at these study areas. We recorded, however, declining natural regeneration of most gum- and resin-bearing species, and this calls for integrated and participatory species management and landscape rehabilitation.

Different arrangements of decentralized forest management have been promoted as alternatives to centralized and top down approaches to halt tropical deforestation and forest degradation. Ethiopia is one of the countries piloting one of these approaches. To inform future programs and projects it is essential to learn from existing pilots and experiences. This paper analyses five of the pilot participatory forest management (PFM) programs undertaken in Ethiopia. The study is based on the Forest User Group (FUG) members' analyses of the programs using selected outcome variables: forest income, change in forest conditions, forest ownership feelings and effectiveness of FUGs as forest managing institutions. These variables were assessed at three points in time-before the introduction of PFM, during the project implementation and after the projects ended. Data were collected using group discussions, key informant interviews and transect walks through the PFM forests. The results show that in all of the five cases the state of the forest is perceived to have improved with the introduction of PFM, and in four of the cases the improvement was maintained after projects ended. Regulated access to the forests following introduction of PFM was not perceived to have affected forest income negatively. There are, however, serious concerns about the institutional effectiveness of the FUGs after projects ended, and this may affect the success of the PFM approach in the longer term.

For forest ecosystem management to be effective, knowledge of the horizontal and vertical structural diversity of a forest is essential. The moist Afromontane highlands of Wondo Genet in south-central Ethiopia present an opportunity to restore and rehabilitate and enhance the ecosystem services to be obtained from this forest sustainably. We focused on the forest structural characteristics to better understand the current forest conditions to assist in the sustainable management of this resource. A total of 75 (20 m × 20 m) quadrats were sampled and diameter at breast height (DBH) ≥ 2 cm and stem height ≥ 2 m were measured. Species identity and abundance, elevation, slope, and aspect were recorded for each plot. Structural characteristics were computed for each plot. Relationship of topographic factors with vegetation characteristics was conducted using R-Software. A total of 72 woody species was recorded. Whereas, the overall diameter distribution shows an inverted J-shaped curve, the basal area followed a bell-shaped pattern. Five types of population structures are revealed. The mean tree density and basal area was 397.3 stems·ha−1 and 31.4 m2·ha−1, respectively. Only 2.8% of the tree species have densities of >25 stems·ha−1 and the percentage distribution of trees show 56.2% in the DBH class 2–10 cm, indicating that the forest is dominated by medium-sized trees. Celtis africana (8.81 m2·ha−1) and Pouteria adolfi-friedericii (5.13 m2·ha−1) make the highest contribution to the basal area and species importance value index. The families/species with the highest importance value index are Ulmaceae, Fabacea and Sapotaceae. Species abundance (r2 =0.32, p

Floristic diversity and the composition of vascular plants are described for the moist Afromontane forest (MAF) of Wondo Genet, south-central Ethiopia. A total of 75 (20 x 20 m) quadrats were sampled and data on species identity, abundance, elevation, slope and aspect were recorded. Different diversity indices and ordination techniques were used to analyze the data. A total of 240 plant species including seven endemic plant species were found representing 94 families and 210 genera, of which trees constitute 23.8%, shrubs 25%, herbs 35%, lianas 11.3% and ferns 5%. Cluster and indicator species analyses revealed five plant communities described as: Teclea nobilis-Calpurnia aurea, Erythrococca trichogyne-Millettia ferruginea, Croton macrostachyus-Vernonia hochstetteri, Protea gaguedi-Rhus retinorrhoea and Dodonaea angustifolia-Hypericum quartinianum. Elevation (R2=0.48, P

Rural households across developing countries rely on diversified sources of income, and forest resources play important role in this regard. This study was designed with the objectives of assessing the contribution of forests to annual income of rural households and identifying its determinants using the case of Jelo Afromontane forest in eastern Ethiopia. It also examined the gender dimensions of forest income, and how this income varies with the wealth status of households. Key informant interview, focus group discussion and household-based questionnaire survey were used to collect data. On average, income from crop production accounted for 40.7% of the total annual household income. Forest income was second in importance, contributing 32.6%. Income from livestock, off- and non-farm activities, and woodlots accounted for 13.6%, 11.4%, and 1.7% of the total household income respectively. Firewood was the most used forest product and constituted the largest proportion (79%) of the total forest income. The contribution of forest income to the total household income varied significantly (P < 0.05) with wealth category. Forest income was more important for poor households (47.3%) than for medium (30.5%) or rich (20.2%) households. It was also more important for female headed households (58.2%) than for male headed households (29%). The gender dimension of forest income was also apparent within the household. Female members generated about four times more forest income (77% of the household forest income) than male members (23%). The sex of the household head (P < 0.01) and distance to the forest (P < 0.05) were the two determinant variables that significantly affected forest income out of the eight explanatory variables considered in the regression model. Policy to promote new forest management arrangement such as participatory forest management (PFM) in Jelo forest needs to take into account the major forest users and the types of products they depend on, and be accompanied with other poverty reduction measures so that improved forest conservation outcome will not have negative consequences on local livelihoods, particularly on poor and women, who depend most on the forest.

Forest resources provide numerous ecosystems services that contribute to building resilient socio-ecological system in the Sahel. They are important natural capital used as safety net during times of drought, which is a common phenomenon in the Sahel region including Ethiopian highlands. The objective of this paper is to indicate the significance of the forests and vegetation of the Sahel region and Ethiopian highland for climate change adaptation and mitigation. There is high amount of carbon stored in the soil and above ground biomass of the forests and vegetation in both the Sahel and the Ethiopian highlands. Both vegetation resources are important for climate change adaptation and mitigation purposes. Despite all these and many other important roles of these forests, they are facing degradation and deforestation problems, in which efforts has to be made for the sustainable management of the forest ecosystems.

While the importance of forests for livelihoods has long been well-recognized, empirical knowledge of the factors influencing the extent and diversity of household engagement in the extraction of forest products across different socio-economic groups remains limited. In this paper, we use primary data collected through a household survey of 180 households in a resettled dry forest areas of Northwestern Ethiopia. The paper mainly aims at identifying the main drivers of household behavior regarding collection of main forest products in the context of dry forest environment. A multivariate probit analysis was used to explain variation in household participation in collection of different forest products. The results show that households' participation in collection of different forest products is significantly determined by a combination of household demographic characteristics, ownership of oxen and of cows, proximity to forest, access to health and school infrastructure, resettlement history and self-reported change in standard of living. The estimation results also suggest households most likely to engage in collection of forest honey, gum, and wood for fuel and other purposes are those located farther from the forest. Policy implications and outlook for further study are discussed in the paper.

Severe drought and large-scale ecosystem degradation are the two major threats exacerbating livelihood vulnerability of the pastoral and agropastoral communities in Borana Zone, southern Ethiopia. Strategic integration and sustainable management of the vast gum and resin bearing dry forests offer significant socioeconomic and ecological opportunities to enhance adaptation of these communities to adverse climatic variability, while enhancing ecosystem resilience. This study was carried out to investigate the diversity, abundance, distribution, and population structure of gum and resin bearing species in Borana drylands. Surveys were carried out in two districts: Arero and Yabello. Seventy-five (20 × 20 m) quadrats were established at 500 m intervals along transects in seven localities. Forty-six woody species distributed in 16 families and 25 genera were encountered. Gum and resin producing species comprised about 42 and 61% of the total number of species, 49 and 68% of the density ha-1, and 73 and 84% of ...

Deforestation in African dry forests is widespread and its drivers are complex and vary in space and time. In this paper, we assessed impacts of immigration on dry forests and options for improved management in a resettlement district in north-western Ethiopia. Key informants interviews, focus group discussions and household questionnaire survey were used to collect data. The results indicated that forests of the district are degrading in spatial coverage and quality. The most important drivers were land use change, excessive wood harvest, grazing pressure and forest fire following immigration. The continuous influx of people with different origins, cultures, religions and lengths of residence in the district underscores absence of social bonds for collective action to regulate access. This, coupled with weak formal regulatory system, market forces and policy incentives for farming, resulted in a near open access situation. Our findings confirm the negative relationships between migration and environment not necessarily because of the mere population number added through immigration but because of lack of regulatory frameworks (formal or informal) and poor social capital. Enforcing existing policy of farm size and putting institutional framework on the ground to regulate rate of immigration, extraction of forest products and to encourage tree planting to meet wood demand are suggested measures. We conclude that Government programmes that opt for resettlement as a measure for poverty alleviation must also have mitigating measures to reducing negative impacts on the natural resource base. Thus, the trade-off between environment and development must be carefully managed. Copyright © 2012 John Wiley & Sons, Ltd.

Declining natural forests and growing demands for wood products are encouraging the rapid expansion of eucalypt farm forestry in Ethiopia, and Arsi Negelle district represents areas with recent plantation expansion in the Rift Valley area of Ethiopia. This study assessed trends in eucalypt planting over the last five decades, identified the determinants, and examined perceptions of local stakeholders towards this expansion in the district. Quantitative data were gathered through a household survey and farm level inventory. About 90% of the respondents had planted eucalypts, and 52% of them were engaged in planting since the late 1990s. About 11% converted cropland to eucalypt woodlots, which is also a growing trend in the area. Proximity to Arsi-Forest Enterprise (P

Farmers' perceptions of soil fertility change were compared with observations on soil quality changes and crop performance in soils from a chronosequence representing a range of soil ages since conversion from forest to cropland (0 to 57 years). A majority of the farmers, 92 per cent, had observed a decline in soil fertility on their land. Farmers use crop yield, indicator plants, soil softness and soil colour to judge soil fertility. They identified 11 plants that they used to indicate high soil fertility and four plants that they used to indicate low soil fertility. There was a strong correlation (r = 0·96) between soil organic matter content (loss on ignition) and farmers' ranking of soil fertility based on colour and softness of soil samples from the chronosequence. The biotest experiment with maize showed an exponential decline in biomass production along the chronosequence, confirming the results of farmers' soil fertility ranking. In the biotest, total soil N predicted produced biomass well (r2 = 0·95), whereas the relationship with soil available P (Olsen) was less obvious. Among the eight analysed plant nutrients in the maize leaves, N content was found to correlate best with biomass production (r2 = 0·94). We conclude (i) that there is good agreement between farmers' knowledge and scientific indicators of soil fertility and (ii) that the major reason for declining soil fertility in Beseku is the decrease in N mineralization over time. Interventions should focus on supporting farmers to implement a diversified nutrient management strategy that can maintain or increase long-term productivity of the soil. Copyright © 2011 John Wiley & Sons, Ltd.

Exclusion of grazing animals and tree plantations are 2 methods that have been used for restoration of degraded lands in tropical semiarid areas. These 2 options can foster secondary forest succession by improving soil conditions, attracting seed-dispersal agents, and modifying microclimate for understory growth. We compared native woody plant diversity and soil chemical and physical attributes under exclosure and on Eucalyptus globulus (EGP) and Cupressus lusitanica (CLP) plantations. Vegetation data were collected by an inventory of stands with circular plots of 5.64 m radius, and soil samples were collected from the 4 corners and center of 20 3 20 m plots. As a result, 15 native woody plant species belonging to 13 families were recorded. Importance value index (IVI), Shannon-Wiener, Simpson’s diversity, and species richness were higher in the exclosure, followed by EGP and CLP. Contents of soil organic carbon and total nitrogen showed significance difference and were highest in the exclosure, followed by CLP, EGP, and grazing land. Although the difference was not significant, an increasing trend was observed for cation exchange capacity and K + . Bulk density was highest on the grazing land, followed by EGP, CLP, and exclosure. Our results suggest that degraded land reclamation can be achieved with plantation of rapidly growing tree species as well as exclosure. However, native woody species diversity and improved soil attributes are better achieved with exclosure. Exclosures can be established interspersed strategically with single- or mixed-species plantations to facilitate restoration of native vegetation. However, it is important to conduct further research on the comparative advantage of enrichment planting of exclosures with preferred tree species or exclosures interspersed within blocks of plantation.

The deliberate maintenance of woody species in traditional agroforestry systems could partly compensate the high rate of deforestation in terms of conserving plant diversity. However, this role of traditional agroforestry is little documented. In this study we assessed the diversity of traditional agroforestry based production systems and their woody plant species across four agro-ecological zones (AEZs) near the central Rift Valley in Ethiopia. A total of 120 farms representing households of three wealth categories—poor, medium and rich—were assessed. A large variety of traditional agroforestry systems combinations existed. In total we identified 86 tree/shrub species belonging to 44 families, 71 of which were indigenous and the rest exotics. 95% of households retained trees while transforming natural forests into agricultural landscapes and 70% complemented with planting. There were variations in woody species richness between the AEZs and wealth classes. Similarly, some socio-economic attribut...

Drylands of Ethiopia, including those in the Rift Valley, host good potential for commercial production of natural gums such as gum arabic. However, little researches have assessed the qualities of these gums for their commercial and industrial promotions. The objectives of this study were to assess the (i) quality of gum arabic collected from naturally grown Acacia senegal trees in the Central Rift Valley of Ethiopia and (ii) evaluate these quality characteristics against reported quality attributes of the same kind of gum from known destinations such as the Sudan and with international specifications. Gum samples were collected from randomly identified 10 trees of A. senegal in the study area and composited into one big sample by putting all in one plastic bag. The characteristics analyzed included: color, odor, moisture content, ash content, viscosity, pH, specific rotation, N and tannin contents, and concentration of several metals using standard laboratory procedures. The results yielded moisture content of 15%, ash content of 3.56%, intrinsic viscosity of 1.19 ml g−1, pH on 25% solution of 4.04, specific rotation of −32.5, nitrogen content of 0.35%, protein content of 2.31% and with no tannin content. Mineral contents of the gum arabic (g/100 g) are Ca 0.7, Mg 0.2, Na 0.01, K 0.95, Fe 0.001, P 0.6 and non-detectable traces of Pb, Co, Cu, Zn, Ni, Cd, Cr and Mn. These values agree well with values of same quality characteristics of gum arabic reported from Sudan and other exporting countries, and also conform well to international standards in all aspects. Indeed, it is possible to utilize the gum arabic resource of the Central Rift Valley of Ethiopia for commercial and/or industrial purposes.

Ethiopia hosts one of the richest flora and fauna resources in tropical Africa. However, this rich bioresource is decreasing due to extensive deforestation. The objectives of this study were to (i) investigate woody species diversity on smallholder cultivated land (crop fields and homegardens) and its implication for biodiversity changes over time; (ii) assess the dynamics of woody species diversity, density and structure with age of crop fields since conversion from natural forest using a chronosequence of farm fields; and (iii) assess the effects of some household and homegarden characteristics on woody species diversity around homegardens in the south-central highlands of Ethiopia. Woody species diversity in the adjacent natural forest was used as a reference. Systematic sampling was used to collect vegetation data from crop fields and natural forest, while simple random sampling within wealth categories was used to select sample households and their homegardens. In total, 70 woody species were recorded. The highest number of woody species (64) was recorded in homegardens, followed by crop fields (32) and the lowest number (31) in remnant natural forest. Despite the low species number, natural forest showed higher Shannon and Simpson diversity indices and Shannon evenness than crop fields and homegardens. This was due to the uniform distribution of species in natural forest compared with homegardens or crop fields. The diversity and density of woody species declined with increasing age of crop fields, while diversity of woody species increased with increasing age and size of homegardens. Wealth status of the households also affected species diversity in homegardens. Rich households kept a greater number of woody species, probably due to their larger-sized homegardens. Generally, the study showed that conversion of natural forest into cultivated land (mosaics of homegardens and crop fields) typical of the smallholder system in the highlands of Ethiopia does not result in a dramatic loss of species but that the spatial distribution, density and species composition may be altered.

Land use and cover changes lead to loss of vegetation cover and subsequent change in soil organic carbon (SOC) and soil quality. This study was carried out in a lake retreat area in the Main Ethiopian Rift Valley, to investigate SOC stock build-up in function of duration of land emergence and SOC dynamics in function of land use and cover changes. Based on an analysis of Landsat imagery (1973, 1986 and 2000), coupled with soil and land use studies, determinants for SOC stock were found. Firstly, SOC stock significantly differed between cultivated land and grazing land (3301 and 2626 g m− 2) on the one hand, and woodland (4594 g m− 2) on the other. Further, only weak relations were found between SOC stock and vegetation index or IR and green band reflectances, which is related to low canopy density (even in woodland) and low leaf density of Acacia during the dry season. The strongest explanation of SOC stock is related to the duration of emergence and hence of pedogenesis. Its proxy, elevation, explains much of the variability of SOC (R2 = 0.48). There is a non-negligible long-term trend of SOC build-up from 4500 g m- 2 under the climax Acacia–Balanites woodland (on land that emerged approximately 4233–4540 BP). Using a multiple regression model involving elevation and presence of forest or woodland, the SOC stock in the study area could be assessed at 3966 (± 1799) g m− 2 SOC in 2000, against 4319 (± 1835) g m− 2 in 1986 and 4199 (± 1866) g m− 2 in 1973, thereby confirming the rapid SOC depletion after removal of vegetation.

Carbon and nutrient release patterns from decomposing leaves in the forest involve initial leaching, a net immobilization by microbes and a net release phase where the nutrient mass decreases. The aim of this study was to assess the effect of disturbance and season (dry and wet) in the carbon (C) and nutrient release patterns from decomposing leaves. The decomposition of a mixed leaf litter in slightly disturbed (SD) and highly disturbed (HD) sites of Boter-Becho forest was investigated during one year. Litterbags of a mixed leaf litter (20 g each) were buried at a depth of 15 cm in the soils. Residual of mixed leaf litter was monthly retrieved, oven-dried (80°C for 24 h) and weighed. Initial leaf litter and decomposing leaf litter were analyzed for C, total nitrogen (N), available phosphorus (P) and potassium (K). Differences in C and nutrients remaining between seasons and site were evaluated by one way ANOVA at P

Frankincense, an aromatic exudate obtained from several Boswellia species, is an important commodity with the potential to invigorate economic development of the drylands of Ethiopia. Local people have been producing and trading frankincense for centuries to diversify their income sources. However, local people's involvement in the production of frankincense varies considerably among the producing dryland regions of the country. The objectives of this study were to investigate: (i) the potential of frankincense production, (ii) socio-cultural, economic and policy factors affecting the involvement of local people in the production of frankincense, and (iii) the current status of Boswellia woodlands in Metema district, which is one of the major frankincense producing areas in Ethiopia. The results showed that Boswellia papyrifera comprised 51% of the species composition of the vegetation of the district with 253.5 kg/ha/year production potential. The total annual frankincense production potential of the district was estimated to be 79,168 tons. However, almost all inhabitants do not benefit economically from the species due to: (i) cultural influence (67%), (ii) unattractiveness of income from frankincense compared to other economic activities in the area (38%), property tenure (27%), government policy on incense production (20%), poor knowledge on frankincense production (19%) and unawareness of the potential of frankincense as a source of income (5%). The absence of direct economic benefits for the local people from the woodlands is triggering their widespread degradation mostly from human induced fire, improper forest use and agricultural land expansion.

Effect of prior land use on the recolonization of native woody species in plantation forests was investigated by assessing naturally regenerating flora (NRF) and soil seed banks (SSB) in plantation forests established on abandoned farmland and cleared natural forest sites in southern highlands of Ethiopia. Eucalyptus saligna and Cupressus lusitanica, two of the most widely planted tree species in the highlands of Ethiopia, were considered in the plantation treatments. About 66 plant species were recorded in the NRF and 55 plant species germinated from the soil samples collected for SSB analysis. Seedlings from the SSB were dominantly herbs, which accounted for 75% of the identified species germinated from the SSB, and native woody species accounted only for 10%. On the contrary, in the NRF native woody species were slightly more dominant (49%) than the herbs (45%). There was high species similarity between the NRF beneath the plantations and the standing vegetation in the adjacent natural forest. On the contrary there was very low similarity between the seedlings emerged from the SSB and the standing vegetation in the adjacent natural forest. Effect of prior land use was apparently stronger on the species composition of the SSB than the species richness of NRF under the plantations. The results also showed that overstory plantation species had stronger influence on the species richness of NRF rather than the pre-plantation land use history. As the SSB of the plantation sites lacked viable seed reserves for most of the naturally regenerating woody plants recorded underneath the plantations of both sites, it was assumed that seed dispersal from the adjacent natural forest has played major role in the recolonization process. From these results it could be shown that establishment of plantation forests either on abandoned farmland or directly on degraded natural forest sites can create comparable enabling environment for the recovery of the native forest flora, even if SSB are devoid of viable seeds of woody species, provided that there is a natural forest in the vicinity to donate seeds.

Depletion of soil organic matter (SOM) is a major component of soil degradation that threatens the sustainability of smallholder farming systems in Ethiopia. In this study, soil organic carbon (SOC) and total nitrogen (N) dynamics following deforestation and subsequent cultivation were evaluated using natural abundance of 13C and 15N along a farm field chronosequence cleared from tropical dry Afromontane forest in south central Ethiopia. Soil samples were collected from five closely located farm fields cultivated for 7, 10, 26, 34 and 53 years after clearance and from an adjacent natural forest soil. All the soils in the study were Mollic Andosols/Humic Haplustands. The δ13C values of the SOC of the farm fields in the 0–10 and 10–20 cm layers were significantly elevated compared to the natural forest soil. In the 0–10 cm layer, the lowest δ13C value of −23.17‰±0.36 was recorded from the natural forest soil and the highest value of −15.7‰±1.50 from the 53-year-old farm field. Fractionation of the SOC of the bulk soil based on the δ13C values showed that in the 0–10 cm layer the SOC of the forest origin declined by 74.6%, which is equivalent to 54.1 Mg C ha−1 or 740 kg ha−1 year−1, where as SOC input from the agricultural crops was low (240 kg ha−1 year−1). However, part of the SOC of the forest origin lost from the surface 0–10 cm soil layer was translocated to the 10–20 cm layer. The SOC derived natural forest approached steady state around 30 years after cultivation while the SOC derived from agricultural crops reached steady state already after 10 years. The results show that the remaining forest derived SOC is recalcitrant while the SOC derived from agricultural crops has a relatively short mean residence time. The soils of the farm fields also showed increasing δ15N values indicating a loss of N from the system. The increasing δ15N values were consistent with the loss of total N along the chronosequence. A continued loss of N combined with insufficient input of fertilizer will result in a decreased productivity of the studied farming systems.

In Ethiopia land degradation in the forms of soil erosion and declining soil fertility are serious challenges to agricultural productivity and economic growth. Despite the general recognition of the threat from land degradation on agricultural productivity, few studies have been made to quantify the extent, rate and process of soil fertility depletion under various land use systems and management practices in the country. In this study we assessed soil chemical and physical property responses to deforestation and subsequent cultivation along a chronosequence of closely located farmlands of different ages (7, 10, 26, 34 and 53 years) since conversion from a tropical dry Afromontane natural forest in Ethiopia. These properties were compared with soil properties under an adjacent natural forest. The changes were used as indicators to evaluate the sustainability of the farm management. All the soils in the study were Mollic Andosols/Humic Haplustands. Soil bulk density (g cm −3 ) in the 0–10 and 10–20 cm soil layers increased significantly while percent pore space decreased significantly in a continuum with increasing cultivation period. Soil C and total N contents (g kg −1 ) in the 0–10 cm soil layer declined significantly and exponentially with increasing years under cultivation. However, in the 10–20 cm soil layer both soil C and total N on the farmlands were significantly higher until after 34 years of continuous cultivation compared to the same soil layer under the natural forest. Consequently, the soil C stock (g m −2 ) of the upper 0.20 m mineral soil was not significantly lower on the farmlands until after 26 years of continuous cultivation compared to the natural forest soil. Available P and K (mg kg −1 ) in the 0–10 cm layer were higher in the soils of the farmlands throughout the 53 years of continuous cultivation compared to the soil under the natural forest. Exchangeable Ca, CEC and base saturation in the 0–10 cm soil layer declined more or less throughout the cultivation period while in the 10–20 cm soil layer they followed the patterns of soil C of that depth. Generally, the magnitudes and rates of degradation of the soil properties following conversion and subsequent cultivation were lower than expected for a low input tropical farming system as the one investigated. Nevertheless, almost all soil quality attributes showed overall declining trends in the long perspective. This continuous decline, albeit slowly, in soil quality with increasing cultivation period indicated that the present land management is not sustainable. Therefore, improved management is imperative to sustain the soil quality and maintain long-term productivity of the farmlands.

The effect of age on calorific value, specific gravity, modulus of rupture (MOR) and modulus of elasticity (MOE) of three plantation grown Eucalyptus species in the south-central highlands of Ethiopia was investigated. The species investigated were Eucalyptus globulus Labill., E. saligna Sm. and E grandis W. Hill ex Maid. The investigation was made on sample trees taken from age sequences of stands of the three species. Calorific values were determined on sample discs taken at 4, 8, 12 and 16 m up the stems of the sample trees. Calorific values were also determined for heartwood and sapwood of each disc separately. Specific gravity, MOR and MOE were investigated on a 1-m long sample log taken from the butt end of each sample tree. The results showed that there was no significant difference in calorific values between the three species when considering a similar age category. Similarly, there was no significant difference in calorific values between disc positions and wood types (heartwood versus sapwood) within species. However, calorific values tend to increase along the tree stem towards the tree top for each of the three species. Correlation between calorific values of each disc position and tree age was generally weak and dominantly negative for E. saligna and E. globulus, but positive for E. grandis. On the other hand, there was a weak but positive correlation between tree age and specific gravity and MOR for the three species. MOE was almost non-correlated with age. Generally, the results showed that waiting for older ages for the three Eucalyptus species may not further increase their calorific values. Hence, stands of the three Eucalyptus species can be harvested and used for fuelwood at an early age as traditionally managed on short-rotation basis.

To assess the effects of canopy characteristics and associated understory environmental factors of tree plantations on native woody species colonization, we measured canopy closure percent (CCP), leaf area index (LAI), understory air and soil temperatures as well as soil moisture in two broadleaved and two coniferous plantations in southern Ethiopia. The plantation species were Cordia africana (indigenous and broadleaved), Eucalyptus saligna (exotic and broadleaved), Cupressus lusitanica (exotic and coniferous) and Pinus patula (exotic and coniferous). The broadleaved species had significantly lower CCP (P

Soil attributes under two fast growing exotic plantations (Cupressus lusitanica and Eucalyptus saligna) established on abandoned farmlands were compared with soils of mechanized farming (MF), traditional farming (TF) and adjacent natural forest in Ethiopia. The plantations were established on an abandoned part of the MF site. All soils in the study were Humic Haplustands. Fifteen years after plantation establishment, the surface soil (0–10 cm) under C. lusitanica had lower bulk density, higher soil C, total N, cation exchange capacity (CEC), base saturation (BS), available K, exchangeable K, Ca, and Mg than the soils of MF and TF. On the contrary, the same soil layer under E. saligna had lower soil C, total N, BS, CEC, available P, available K, and exchangeable Ca than the soils of TF and MF. Except for some soil properties under C. lusitanica that showed consistently high concentrations, most soil properties in the sub-soil layers (10–20 and 20–40 cm) did not show clear differences between the sites as in the surface 0–10 cm soil layer. Comparison of the two farming situations showed higher soil compaction and poorer soil status under MF than TF. Computed deterioration index (DI) revealed a high positive index for the soil under C. lusitanica (DI=+337) suggesting a cumulative positive effect of the species on soil properties. Soil properties deteriorated under E. saligna (DI=−198) even compared to the soils subject to MF and TF (DI=−185 and −77, respectively). We concluded that forest plantations can be used to facilitate soil restoration on degraded farmlands, but that the degree, rate and direction of changes in soil attributes are species dependent. We suggest that long-term effects on soil properties should be considered as one of the criteria when selecting species for afforestation or reforestation of degraded farmlands.

Oleo-gum resins, hardened resinous plant exudates obtained from some Acacia, Boswellia and Commiphora species in the lowlands of Ethiopia, have been traded for centuries both on the international and domestic markets. However, their economic contribution to the rural households is little documented. A reconnaissance survey was carried out in Liban, one of the administrative zones in the Ethiopian Somali National Regional State, to investigate major oleo-gum-resins collected for commerce and their economic contributions to rural households. The results showed that five types of oleo-gum-resins are collected for commerce in Liban. These are gum arabic obtained from Acacia Senegal, gum talha obtained from A. seyal, frankincense obtained from Boswellia neglecta and B. ogadensis, myrrh obtained from Commiphora myrrha (syn. C. molmol), C. truncata and C. borensis and hagar obtained from C. africana. The average annual cash income generated per household was estimated to be US$ 80.00. This income contributes to 32.6% of annual household subsistence, and ranks second after livestock in the overall household livelihood. The contribution from crop farming was estimated to be 12%, which is about one-third of the contribution from oleo-gum resins. These results show that oleo-gum resins obtained from the vegetation resources play a significant role in the economy of rural households in Liban. The vegetation resources and their oleo-gum resins also provide various goods and services for the rural households in Liban. Fodder for livestock, traditional medicines for human and livestock disease treatments, incense for fumigation, cultural and religious rituals, and emergency foods during droughts are among the most common. Opportunities and constraints for oleo-gum-resin-based development in Liban and other similar areas in Ethiopia are discussed. The results could be used as baseline information for evaluating the potential of the arid and semi-arid land vegetation resources of the country, to plan for extensive studies of their management, conservation and proper utilization.

In Ethiopia, deforestation rates remain high and the gap between demand and domestic supply of forest products is expanding, even though government-initiated re-greening efforts began over a century ago. Today, over 3 million hectares (ha) of degraded forest land are under area exclosure; smallholder plantations cover 0.8 million ha; and state-owned industrial plantations stagnate at under 0.25 million ha. This review captures experiences related to re-greening practices in Ethiopia, specifically with regards to area exclosure and afforestation and reforestation, and distills lessons regarding processes, achievements and challenges. The findings show that farmers and non-governmental organizations (NGOs) are the main players, and that the private sector has so far played only a small role. The role of the government was mixed: supportive in some cases and hindering in others. The challenges of state- and NGO-led re-greening practices are: inadequate involvement of communities; poorly defined rehabilitation objectives; lack of management plans; unclear responsibilities and benefit-sharing arrangements; and poor silvicultural practices. The lessons include: a more active role for non-state actors in re-greening initiatives; more attention to market signals; devolution of management responsibility; clear definition of responsibilities and benefit-sharing arrangements; and better tenure security, which are all major factors to success.