Search

Ziziphus spina-christi is a multipurpose tree which grows naturally on the farm lands in Habru district. Since, the effects of this tree on soil and crop have not scientifically quantified; this study has been carried out with the aim of assessing the effect of Ziziphus spina-christi on soil physicochemical properties, grain and biomass yield of sorghum.Five isolated and nearly identical Ziziphus spina-christi tree growing on farm lands with similar site condition were selected and canopy coverage of each tree was divided into four radial transects. Soil samples from three horizontal distances: 1.2m, 2.9m and 15m with two soil depths (0–15cm and 15-30cm) were taken for analysis of soil physico- chemical properties. Three quadrates 1m x1m at each transect and distances were laid for sorghum grain yield and biomass estimation. The result shows that soil pH, EC, CEC and soil texture were not significantly (p>0.05) influenced by Ziziphus spina-christi tree, whereas soil bulk density, soil moisture content, total nitrogen, organic carbon, available phosphorus and exchangeable cation (Mg, Ca and K) were significantly (P0.05).Hence, retaining of this tree on crop land improves the soil fertility status.

The establishment of grazing exclosures is widely practiced to restore degraded agricultural lands and forests. Here, we evaluated the potential of grazing exclosures to contribute to the “4 per 1000” initiative by analyzing the changes in soil organic carbon (SOC) stocks and sequestration (SCS) rates after their establishment on degraded communal grazing lands in Tigray region of Ethiopia. We selected grazing areas that were excluded from grazing for 5 to 24 years across the three agroecological zones of the region and used adjacent open grazing lands (OGLs) as control. Soil samples were collected from two depths (0–15 cm and 15–30 cm) and SOC and aboveground C stocks were quantified in both exclosures and OGLs. The mean SOC stock and SCS rate in exclosures (0–30 cm) were 31 Mg C ha−1 and 3 Mg C ha−1 year−1, which were respectively 166% and 12% higher than that in the OGLs, indicating a positive restoration effect of exclosures on SOC storage. With increasing exclosure age, SOC stock and SCS rate increased in the exclosures but decreased in the OGLs. Higher SOC stock and SCS rate were recorded in 0–15 cm than in 15–30 cm. The relative (i.e., to the SOC stock in OGLs) rates of increase in SOC stocks (70–189‰ year−1) were higher than the 4‰ year−1 and were initially high due to low initial SOC stock but declined over time after a maximum value of SOC stock is reached. Factors such as aboveground biomass, altitude, clay content and precipitation promoted SOC storage in exclosures. Our study highlights the high potential of exclosures for restoring SOC in the 0–30 cm soil depth at a rate greater than the 4‰ value. We argue that practices such as grazing exclosure can be promoted to achieve the climate change mitigation target of the “4‰” initiative.

Grazing exclosures have been promoted as an effective and low-cost land management strategy to recover vegetation and associated functions in degraded landscapes in the tropics. While grazing exclosures can be important reservoirs of biodiversity and carbon, their potential in playing a dual role of conservation of biodiversity and mitigation of climate change effects is not yet established. To address this gap, we assessed the effect of diversity on aboveground carbon (AGC) and the relative importance of the driving biotic (functional diversity, functional composition and structural diversity) and abiotic (climate, topography and soil) mechanisms. We used a dataset from 133 inventory plots across three altitudinal zones, i.e., highland, midland and lowland, in northern Ethiopia, which allowed local- (within altitudinal zone) and broad- (across altitudinal zones) environmental scale analysis of diversity-AGC relationships. We found that species richness-AGC relationship shifted from neutral in highlands to positive in mid- and lowlands as well as across the altitudinal zones. Structural diversity was consistently the strongest mediator of the positive effects of species richness on AGC within and across altitudinal zones, whereas functional composition linked species richness to AGC at the broad environmental scale only. Abiotic factors had direct and indirect effects via biotic factors on AGC, but their relative importance varied with altitudinal zones. Our results indicate that the effect of species diversity on AGC was altitude-dependent and operated more strongly through structural diversity (representing niche complementarity effect) than functional composition (representing selection effect). Our study suggests that maintaining high structural diversity and managing functionally important species while promoting favourable climatic and soil conditions can enhance carbon storage in grazing exclosures.

In response to the 2011 Bonn Challenge, Ethiopia has committed to restoring 15 million ha of degraded forest and savannah. This study focuses on rehabilitation of communal lands in Tigray through the use of exclosures. Exclosures, often established by using so-called social fences in Ethiopia, are widely recognized as effective in restoring vegetation. This study identified factors contributing to the success of exclosures. After selecting nine successful exclosures from three agro-ecological zones, data were collected through a formal survey of 324 randomly selected households, and from focus group discussions and key informant interviews. Local communities recognize the role of exclosures in increasing site productivity and vegetation cover. However, this positive attitude is often challenged by shortages of livestock feed as a competing priority. Results of our analysis are presented here, bringing insights on factors affecting successful planning and implementation of exclosures and their wider adoption as a means of landscape rehabilitation.

The greatest extent of Afromontane environments in the world is found in Ethiopia. These areas support exceptional biodiversity, but forest cover and ecological integrity have declined sharply in recent decades. Conservation and management efforts are hampered in part by an inadequate understanding of the basic ecology of major tree species. We investigated population structure and inferred population dynamics from size frequency distributions of 22 forest tree species encountered in montane forests of Ethiopia. We collected new empirical data from four sites in the Bale Mountains, where some of the country's most extensive and least disturbed forests remain, and conducted a systematic review and analysis of all such studies that reported population structure for one or more of these species in Ethiopia. Thirteen widespread montane tree species showed a reverse-J size distribution, indicating a relatively stable population structure. Six other species had size-frequency distributions that indicate episodic recruitment and/or removal of certain size classes. Specific causes of these patterns are uncertain: they may involve timber harvesting, herbivory, fire, or natural disturbances, but patterns were inconsistent and locality dependent. For three other tree species, existing data are inadequate for any interpretation of population structure and dynamics. A species of particular conservation concern that emerged from this analysis was Hagenia abyssinica, which was found in all areas to consist only of larger individuals with no recent recruitment. For management and conservation purposes, the species in most urgent need of new research are those with inadequate or inconsistent data, and H. abyssinica.

The main objective of this study was to determine how the conversions of home gardens to mono-crop fields affect soil organic carbon (SOC) and total nitrogen (TN) stocks. The study compared SOC and soil TN stocks in 7 paired sites of home gardens and converted mono-crop fields (khat and sugar cane; cultivated for 1–20 years after conversion) in Wondo Genet, Southern Ethiopia. Except two recently converted mono-crop fields (1 and 4 years after conversion), most of converted mono-crop fields had significantly lower contents of SOC (18.3–47.1 %) and soil TN (14.9–45 %) compared to home gardens. Converted mono-crop fields over 10–20 years old showed significantly lower SOC stocks (18.2–30.2 %) and soil TN stocks (16.7–28.7 %) compared to home gardens. There was no significant relationship between the periods after conversion and the rate of decrease of SOC and TN stocks in the mono-crop fields. Study results show that conversion of home gardens to mono-crop fields decreases SOC and TN stocks. Further studies are needed to identify the major mechanisms causing the decrease and quantify the change of SOC and TN in different environment and climate conditions.

Carbohydrates fixed by photosynthesis are stored in plant organs in the form of starch or sugars. Starch and sugars sum to the total non-structural carbohydrate pool (TNC) and may serve as intermediate pools between assimilation and utilization. We examined the impact of tapping on TNC concentrations in stem-wood, bark and root tissues of the frankincense tree (Boswellia papyrifera (Del.) Hochst) in two natural woodlands of Ethiopia. Two tapping treatments, one without tapping (control) and the other with tapping at 12 incisions, are applied on experimental trees. Trees are tapped in the leafless dry period, diminishing their carbon storage pools. If storage pools are not refilled by assimilation during the wet season, when crowns are in full leaf, tapping may deplete the carbon pool and weaken Boswellia trees. The highest soluble sugar concentrations were in the bark and the highest starch concentrations in the stem-wood. The stem-wood contains 12 times higher starch than soluble sugar concentrations. Hence, the highest TNC concentrations occurred in the stem-wood. Moreover, wood volume was larger than root or bark volumes and, as a result, more TNC was stored in the stem-wood. As predicted, tapping reduced the TNC concentrations and pool sizes in frankincense trees during the dry season. During the wet season, these carbon pools were gradually filled in tapped trees, but never to the size of non-tapped trees. We conclude that TNC is dynamic on a seasonal time scale and offers resilience against stress, highlighting its importance for tree carbon balance. But current resin tapping practices are intensive and may weaken Boswellia populations, jeopardizing future frankincense production.

Customs has been described for a century as a gate keeper, with customs authorities representing a barrier through which international trade must pass. But currently Customs plays a critical role in the implementation of a range of trade, economic and social policies and contributes to the achievement of national development objective focusing on trade facilitation and regulatory control. Trade facilitation and customs regulatory control regarded as two major requirements for both government and the business community in pursuing their national and international trade in the competitive environment of today. However, enormous amount of time and money wasted due to long delays at customs in most sub-Sahara African Countries like Ethiopia. The objective of this study was to identify the challenges of customs in export trade facilitation at Dire Dawa Customs Branch Office. To achieve the research objective, the study employed a descriptive method and used both qualitative and quantitative research approach. Primary data were collected from all Customs employees found in export clearance team, and all exporters and customs clearing agents who have permanent office at the branch. Accordingly 85 questionnaires were distributed and interviews have made with purposively selected 3 team leader, 2 process owners and 1 Deputy Branch manager. The collected data were analyzed using descriptive statistics. Four major findings from the case study are identified as the key criteria required for facilitating international trade. First, risk management is identified as a core principle of accommodating facilitation. Second, customs laws and regulations, customs procedures and information technology are found to be key instruments for supporting the achievement of trade facilitation. Third, comprehensive and integrated approaches to cooperation are regarded as enablers, which contribute to facilitation. Finally, human resource development is identified as a prerequisite to support all other elements in accommodating trade facilitation. The accommodation of trade facilitation can be achieved dependent on these key criteria being effective and consistent with international standards and guidelines. Despite the effort of the Dire Dawa Customs Branch Office to accommodate trade facilitation, the study identifies some discrepancies between 'policy and implementation' or 'principles and practices', particularly in the areas of risk management, customs procedures and information technology. These implementation problems are found to result mainly from the lack of skills and knowledge of the customs officers. A key finding of the study is that continuous and sustainable development of human resources in terms of customs competency is required to ensure transparency, consistency and predictability in providing customs services. Finally, the challenges of customs vary from branch to branch and even from one customs procedure to another depending on the nature of the branch as the study entirely delimited to study the issues of Dire Dawa Customs Branch Office; it does not represent the scene in other Branch office and other customs procedures. Thus, further research needs to be conducted to address this customs challenges in export trade facilitation. Key words: Customs Automation, Risk Management, Human Resource Development and Management, Cooperation and Coordination among customs and other agencies, Customs Procedures, Customs Laws and Regulations

A conceptual model was tested for explaining environmental and physiological effects on leaf gas exchange in the deciduous dry tropical woodland tree Boswellia papyrifera (Del.) Hochst. For this species we aimed at (i) understanding diurnal patterns in leaf gas exchange, (ii) exploring cause-effect relationships among external environment, internal physiology and leaf gas exchange, and (iii) exploring site differences in leaf gas exchange in response to environmental variables. Diurnal courses in gas exchange, underlying physiological traits and environmental variables were measured for 90 trees on consecutive days at two contrasting areas, one at high and the other at low altitude. Assimilation was highest in the morning and slightly decreased during the day. In contrast, transpiration increased from early morning to midday, mainly in response to an increasing vapor pressure deficit (VPD) and gradual stomatal closure. The leaf water potential varied relatively little and did not influence gas exchange during the measurement period. Our results suggest that the same cause-effect relationships function at contrasting areas. However, leaves at the higher altitude had higher photosynthetic capacity, reflecting acclimation to higher light levels. Trees at both areas nevertheless achieved similar leaf assimilation rates since assimilation was down-regulated by stomatal closure due to the higher VPD at the higher altitude, while it became more light limited at the lower altitude. Gas exchange was thus limited by a high VPD or low light levels during the wet season, despite the ability of the species to acclimate to different conditions.

There has been an incessant conversion of natural forests to agricultural land uses such as farmlands, grasslands and parkland agro-forestry in Africa during the last century. This study investigated changes in soil organic carbon (SOC) and total nitrogen (TN) stocks following the conversion of a natural forest to coffee-based agro-forestry, grazing grassland and well-managed maize farm in a sub-humid tropical climate of Ethiopia. Soil samples (up to 1m depth) were taken from each of these four land use types. Taking the natural forest as a baseline and with duration of 35 years since land use conversion, the total SOC and TN stocks were not significantly different (P > 0.05) among the different land use types when the entire 1m soil depth was considered. However, in the upper 0-10cm soil depth, the SOC and TN stocks were significantly higher (P < 0.05) in the natural forest than the agricultural land use types. There were different patterns of SOC and TN distributions along the soil depths for the different land use types. The SOC stocks decreased with depth in natural forest, but did not show any increasing or decreasing trends in maize farm, grazing grassland, and coffee-based agroforestry. The results of this study revealed that the negative effects of converting natural forests to agricultural land use types on SOC and TN can be prevented through appropriate land management practices in cultivated and grazing lands and use of proper agroforestry practices in a sub-humid tropical climate.

Much of the Earth is degraded, is being degraded, or is at risk of degradation. Dry Afromontane forests in Ethiopia are one of the ecosystems affected by this phenomenon. This study focuses on assessment of community perceptions of experiences with, and benefits from, enclosure practices meant to prevent or mitigate land degradation. Communities around Biyo-Kelala and Tiya enclosure areas, in central and northern Ethiopia respectively, were used for the study. The assessment was carried out on the basis of a semi-structured questionnaire survey and focus group discussions. Results showed that an overwhelming majority of the people have a positive attitude about enclosures and feel that they have gained benefits. However, people prefer not to ensure private ownership, but favor maintaining the existing communal (village level) management system instead. This demonstrates that groups emerge to manage common property when they live close to the resource. Yet the issue of benefits and their equitable...

Whole-crown carbon gain depends on environmental variables and functional traits, and in turn sets limits to growth sinks of trees. We estimated the annual whole-crown carbon gain of trees of the species Boswellia papyrifera, which are tapped for frankincense, by integrating leaf photosynthetic rates over the total leaf area and leaf life span. We examined the effect of tapping on total leaf area and leaf photosynthesis and, in turn, on carbon gain and resin yield for trees of a dry highland population and a wetter lowland population. Highland and lowland trees had similar total leaf area, but highland trees had higher photosynthetic rates per unit leaf area than lowland trees since they received more light and had higher photosynthetic capacities. Highland trees therefore achieved a higher annual carbon gain than lowland trees, despite a shorter rainy season and shorter leaf lifespan. Intensive tapping reduced crown leaf area and the carbon gain in the lowland trees, but not in highland trees. These results highlight how the interplay between local conditions and functional traits determine regional variation in tree productivity. However, such differences in productivity and carbon gain did not influence frankincense yield across sites. We conclude that tapping B. papyrifera trees reduces annual carbon gain but the extent differs among different populations.

The purpose of this thesis is to explore factors, actors and processes which condition innovative commercialization of bamboo in Ethiopia. The thesis particularly focuses on how traditional technologies and entrepreneurial innovations can be a source of knowledge and foundation for bamboo commercialization in Ethiopia. In tandem with technology development, it also attempts to shed light on how variations in value chains and market availability result in differential levels of commercialization. The research is designed based on the system of innovation and value chain approaches as main theoretical lenses. Data is collected from three districts and cities. The main data collection method was surveys of key value chain actors, complemented by expert interviews, case studies, group discussions and analysis of secondary data sources. Both qualitative and quantitative techniques including inferential statistics are used for analysis. The results demonstrate that traditional knowledge and technical skills are key sources of innovation for bamboo commercialization. These technical skills are gradually transferred from rural to urban and from traditional to semi-modern via recreational houses and furniture production. The research found that the major factors which significantly explain the differences in technical skills are bamboo income, use knowledge, market distance and management regimes. The study further reveals that there are diversity of enterprises which have a major role both in generation of innovation and production of value added products. Innovation performance is influenced by level of technology, financial access and business experience while economic performance is influenced by the age of the enterprise owner, their innovativeness, level of technology and location (urban functions). Institutional actors play an intermediary role at the production and processing levels in promoting bamboo sector development through training provision, policy development and linking actors along the value chain. Similarly, consumers are also key actors in the value chain and are the major drivers of bamboo commercialization. Rates of commercialization are found different among regions where areas with a better access to consumer markets reportedly engage more in commercial extraction and earn a correspondingly higher income from bamboo than regions far from centers of consumption. In summary, the empirical analysis depicts that innovative commercialization is the result of a combination of technological capability, entrepreneurial competency and market accessibility. Thus, future policy for bamboo resource commercialization and development should be geared towards establishing and nurturing a bamboo sector innovation system which in turn supports the development of technology-led resource commercialization and facilitates entry into the global value chain. Diese Dissertation hat zum Ziel, Faktoren, Akteure und Prozesse zu erforschen, welche die innovative Kommerzialisierung von Bambus in Äthiopien bedingen. Insbesondere wird in dieser Arbeit darauf eingegangen, inwiefern traditionelle Technologien und unternehmerische Innovationen eine Wissensquelle und ein Fundament für die Bambuskommerzialisierung in Äthiopien sein können. Zusammen mit der Technologieentwicklung wird auch dargestellt, wie Variationen in der Wertekette und der Marktverfügbarkeit zu unterschiedlichen Graden der Kommerzialisierung führen. Die Forschung basiert auf dem System von Innovations- und Wertekettenverfahren als grundlegende theoretische Aspekte. Die Datenerhebung erfolgte in drei Distrikten und Städten. Die Haupterfassungsmethode war die Befragung von Schlüsselakteuren in den Werteketten, ergänzt durch Experteninterviews, Fallstudien, Gruppendiskussionen sowie Analysen von sekundären Datenquellen. Sowohl qualitative als auch quantitative Verfahren einschließlich der Interferenzstatistik dienen der Analyse. Die Ergebnisse zeigen, dass traditionelles Wissen und technische Fertigkeiten Schlüsselquellen für Innovationen in der Bambuskommerzialisierung sind. Diese technischen Fertigkeiten werden nach und nach vom Ländlichen zum Städtischen sowie vom Traditionellen zur Semimoderne überführt, was sich hauptsächlich durch den Erholungssektor sowie durch die Möbelherstellung zeigt. Die Forschung fand heraus, dass die Hauptfaktoren der Unterschiede in den technischen Fertigkeiten das durch Bambus erzielte Einkommen, das Wissen über dessen Verwendung, die Distanz zum Markt sowie Managementregime sind. Ferner zeigten die Untersuchungen, dass es eine Vielfalt von Betrieben gibt, welche eine Hauptrolle sowohl bei Innovationen als auch bei der Herstellung höherwertiger Produkte spielen. Die Innovationsleistung wird beeinflusst durch den Stand der Technik, durch finanziellen Zugang sowie Businesserfahrungen, während die ökonomische Leistung beeinflusst wird durch das Alter der Betriebsbesitzer, deren Innovation, den Stand der Technik, sowie durch die Lage (urbane Funktionen). Institutionelle Akteure spielen eine Zwischenrolle auf Produktions- und Verarbeitungsebene bei der Förderung der Entwicklung des Bambussektors durch Bereitstellung von Ausbildung, der Entwicklung von Methoden und verbindenden Akteuren entlang der Wertekette. Ähnlich sind auch die Konsumenten Schlüsselfaktoren in der Wertekette sowie Hauptantrieb für die Bambuskommerzialisierung. Die Kommerzialisierungsraten in den einzelnen Regionen sind unterschiedlich, wobei Gebiete mit besserem Marktzugang eine größere Kommerzialisierung bewirken und ein besseres Bambus-basiertes Einkommen erzeugen als Regionen, die sich fernab von den Zentren der Konsumption befinden. Zusammenfassend kann ausgeführt werden, dass die empirische Analyse zu dem Schluss kommt, dass innovative Kommerzialisierung das Ergebnis einer Kombination technischer Fähigkeit, unternehmerischer Kompetenz sowie der Marktzugänglichkeit ist. Folglich ist die zukunftsorientierte bambusbasierte Kommerzialisierung und Entwicklung so zu lenken, dass das Innovationssystem auf dem Bambussektor etabliert und gestärkt wird, wodurch auch die Entwicklung technologiegeführter Ressourcenkommerzialisierung gefördert sowie der Zugang zur globalen Wertekette begünstigt wird.