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Natural forests are crucial for climate change mitigation and adaptation, but deforestation and degradation challenges highly reduce their value. This study evaluates the potential of natural forest carbon stock and the influence of management interventions on enhancing forest carbon storage capacity. Based on forest area cover, a study was conducted in nine purposely selected forest patches across various forest ecosystems. Data on diameter, height, and environmental variables from various forest management approaches were collected and analyzed with R Ver. 4.1. The findings revealed a substantial difference (p.029) in carbon stock between environmental variables and management interventions. The findings revealed a strong connection between environmental variables and the overall pool of carbon stock within forest patches (p.029). Carbon stocks were highest in the Moist‐montane forest ecosystem (778.25 ton/ha), moderate slope (1019.5 ton/ha), lower elevation (614.50 ton/ha), southwest‐facing (800.1 ton/ha) and area exclosures (993.2 ton/ha). Accordingly, natural forests, particularly unmanaged parts, are sensitive to anthropogenic stresses, decreasing their ability to efficiently store carbon. As a result, the study highlighted the importance of sustainable forest management, particularly area exclosures and participatory forest management, in increasing forest carbon storage potential. [ABSTRACT FROM AUTHOR]

Backgorund: Forest plays an important role in the global carbon cycle by sequestering carbon dioxide and thereby mitigating climate change. In this study, an attempt was made to investigate the effects of land use/land cover (LULC) change (1989–2017) on carbon stock and its economic values in tropical moist Afromontane forests of the Majang Forest Biosphere Reserve (MFBR), south-west Ethiopia. Systematic sampling was conducted to collect biomass and soil data from 140 plots in MFBR. The soil data were collected from grassland and farmland. InVEST modelling was employed to investigate the spatial and temporal distribution of carbon stocks. Global Voluntary Market Price (GVMP) and Tropical Economics of Ecosystems and Biodiversity (TEEB) analysis was performed to estimate economic values (EV) of carbon stock dynamics. Correlation and regression analyses were also employed to identify the relationship between environmental and anthropogenic impacts on carbon stocks. Results: The results indicated that the above-ground carbon and soil organic carbon stocks were higher than the other remaining carbon pools in MFBR. The mean carbon stock (32.59 M tonne) in 2017 was lower than in 1989 (34.76 Mt) of MFBR. Similarly, the EV of carbon stock in 2017 was lower than in 1989. Elevation, slope, and harvesting index are important environmental and disturbance factors resulting in major differences in carbon stock among study sites in MFBR. Conclusions: Therefore, the gradual reduction of carbon stocks in connection with LULC change calls for urgent attention to implement successful conservation and sustainable use of forest resources in biosphere reserves. [ABSTRACT FROM AUTHOR]

Background: In Ethiopia, highland bamboo has been cultivated in various niches: farmlands, riverbanks, woodlot boundaries, and homesteads, and agroforestry systems. However, the biomass and carbon storage of potential of bamboo forests across niches is not well characterized in Ethiopia. Therefore, this study was conducted to estimate the biomass and carbon storage potential of highland bamboo plantations in northwestern Ethiopia. To this end, a total of 60 circular plots measuring 100 m2 with a radius of 5.64 m were randomly established on the homestead, woodlot, and riverbank plantation niches to conduct the inventory. The biomass storage of bamboo was calculated based on previously published allometric equations. Biomass and carbon stock variations among age-classes and niches of bamboo forests were analyzed using analysis of variance (ANOVA) and subsequent pairwise means comparisons of carbon stocks among niches were performed via post hoc Tukey test at p < 0.05. Results: Results showed that the mean aboveground biomass (AGB) ranged from 150.18 – 191.42 Mg ha−1 in the entire niches. The highest amount of AGB was stored in the homestead niche (191.42 Mg ha−1) followed by the woodlot (180.11 Mg ha−1) and riverbank niche (150.17 Mg ha−1), respectively. The highest carbon stock (111.56 Mg C ha−1) was found in the homestead niche while the smallest amount was recorded in the riverbank niche (87.52 Mg ha−1). The homestead bamboo plantation has the highest biomass storage due to the application of manure and natural fertilizer, regular harvesting and management of culms, and protection from illegal harvesting and grazing. Conclusion: This study highlights the importance of bamboo plantations in climate change mitigation. Hence, bamboo plantation should be promoted; and natural resource management and forestry departments of the government, Universities, research centers, the International Bamboo and Rattan Organization (INBAR), and other partners should work with local communities to expand bamboo plantation on their homesteads and degraded lands. [ABSTRACT FROM AUTHOR]

Forests play an important role in combating the challenges posed by changing climate through sequestering carbon in their living biomasses and the soil. Tropical forests, which harbour a large number of species, are anticipated to play a great role in this regard due to the favourable growing environments. However, there is limited knowledge of the variability in carbon stock among land use types and its relationship with biodiversity. Therefore, this study assessed the variability in storing the different carbon pools among natural forest, woodland and khat plantation land use types. It also explored the relationship between biodiversity and carbon storage in the different carbon pools. Plant inventory and sample collection were undertaken following standard methods. In addition, soil samples were taken at three depth profile classes of 0–30 cm (top layer), 30–60 cm (middle layer) and 60–100 cm (bottom layer). Results of the study revealed that there was no statistically significant relationship between biodiversity and total biomass carbon, soil organic carbon or total carbon stock at a 95% level of confidence. The results indicated that the natural forest had the highest plant biomass (456.93 Mg ha−1) followed by woodland (19.78 Mg ha−1) and khat plantation (2.46 Mg ha−1). Consequently, the total carbon stock estimate of the natural forest (366.47 Mg ha−1) was significantly larger than that of the woodland (141.85 Mg ha−1) and khat plantation (125.86 Mg ha−1). The variation in total carbon stock among land use types arises from the variation in the total biomass carbon stock. The study results also revealed that soil organic carbon stock decreased with soil depth in all the land-use types. The findings of this study have implication of improving topsoil management in monoculture crops such as khat plantation and conserving natural forests for enhancing carbon sequestration potentials. [ABSTRACT FROM AUTHOR]

This study was conducted at Gara Gola, in the Oromia regional state of Ethiopia, to examine the carbon sequestration potentials under three altitudinal gradients [i.e., Lower altitude (LA: 1500-1800 m.a.s.l.); Middle altitude (MA: 1801-2000 m.a.s.l.) and upper altitude (UA: 2001-2300 m.a.s.l.)]. A total of 60 quadrats of 20m x 20m, 5m x 5m, and 1m x 1m with six horizontal transect lines were employed to gather data on the tree, shrub, herbaceous, and soil, respectively. To estimate organic carbon percentage, soil parameters were collected from three soil profiles (i.e., 0 to 10 cm, 10 to 20 cm, and 20 to 30 cm). The mean total carbon stock of the study area was 641.18 Mg ha-1. MA had relatively higher TC than the other gradients. But the LA had the lowest TC stock, due to a high amount of human and animal interference. The results showed that the UA had significantly higher above-ground (AGC) and below-ground carbon (BGC) stocks with 147.3±39.4 Mg ha-1 and 18.37±7.8 Mg ha-1, respectively, compared to other gradients. However, LA had the lowest AGC (66.8±8.7 Mg ha-1) and BGC (12.06±2.6 Mg ha-1). Lower altitude exhibited a significantly higher SOC value than the other two altitudinal gradients followed by MA. The UA had the lowest SOC value. SOC across the three soil profiles follows a reduction trend from topsoil depth to lower soil depth with significant variation. In conclusion, LA should embrace better ecological, policy, and socioeconomic considerations than the other gradients. [ABSTRACT FROM AUTHOR]

Grazing management strategies tend to have different effects on rangeland plant production. Changes in grazing management can, therefore, affect the carbon stock potential of rangelands. Despite rangeland ecosystems being important global sinks for carbon, we know relatively little about the effect of traditional grazing management practices on their potential to store carbon. In this study, we evaluated the carbon stock and change rate of rangelands using three traditional grazing management practices in the semiarid pastoral ecosystem of eastern Ethiopia. By comparing data on vegetation and soil carbon stocks, we found that there was a strong significant difference (p < 0.001) between these different management practices. In particular, the establishment of enclosures was associated with an annual increase in carbon stocks of soil (3%) and woody (11.9%) and herbaceous (57.6%) biomass, when compared to communal open lands. Both enclosure and browsing management practices were found to have the highest levels of soil organic carbon stocks, differing only in terms of the amount of woody and herbaceous biomass. Thus, modest changes in traditional grazing management practices can play an important role in carbon storage and sequestration. Further research is required on a wider range of traditional pastoral management practices across space and time, as understanding these processes is key to combating global climate change. [ABSTRACT FROM AUTHOR]

The conversion of fertile croplands to Eucalyptus woodlots in Ethiopian highlands, due to its business attractiveness to smallholders, raises concerns related to food production, water resources, carbon and other ecosystem services. This study was therefore designed to examine land allocation and plantation management decisions. Our emphasis was on the analysis of tradeoffs between the economic gains obtained from harvesting Eucalyptus timber and food production, carbon and water use. For that purpose, we considered a 1987 ha agroforest landscape in the Amhara region, Northern Ethiopia. With a planning horizon covering nine one-year periods, we developed and used nine Model I single objective linear programming (LP) models, and analyzed tradeoffs between objectives (e.g., land expectation value (LEV), Carbon, volume of ending inventory (VolEI), crop production and water use) using an LP-based Pareto frontier approach. The study revealed that the objective of maximizing the total economic gain from the sale of Eucalyptus wood poles favored a complete conversion of the available cropland into Eucalyptus woodlots. To meet the minimum annual crop production/consumption/requirements of households in the study area, the land under Eucalyptus should be limited to 1772 ha, with a sequestration potential of 1.5 to 1.57 × 107 kg yr−1 of carbon in the aboveground biomass. However, this land cover limit should be decreased to 921 ha so as to limit the total annual water use (for biomass production) below the amount available from rainfall (11,000 m3 ha−1 yr−1). Moreover, the study highlighted that maximizing the harvested wood volume or LEV would come at the cost of a decreased aboveground carbon stock and volume of ending inventory and higher total water use. It also provided alternative optimal Pareto-front points, among which decision makers will be able to select their preferred targets. The current study also showed the potential for the application of Pareto frontier approaches to support the development of effective ecological/economic management strategies and the design of land use policies in an Ethiopian context. [ABSTRACT FROM AUTHOR]

Background: Allometric equations are used to estimate biomass and carbon stock of forests. In Ethiopia, despite the presence of large floral diversity, only a few site-specific allometric equations have been developed so far. This study was conducted in the Omo-Gibe woodland of south-western Ethiopia to develop an allometric equation to estimate the Above-ground Biomass (AGB) of the four Acacia species (Senegalia polyacantha, Vachellia seyal, Vachellia etbaica and Vachellia tortilis). Fifty-four (54) Acacia trees were sampled and measured within 35 temporarily established square plots. In each plot, dendrometric variables were measured to derive the models based on combinations of Diameter at Breast Height (DBH), height, and wood density as predictor variables. Model performance was evaluated using goodness-of-fit statistics. The biomass was compared using four allometric biomass models that have been widely used in the tropics. Results: The model containing DBH alone was more accurate to estimate AGB compared to the use of multiple predictor variables. This study, therefore, substantiated the importance of site-specific allometric equations in estimating the AGB of Acacia woodlands. This is because a site-specific allometric equation recognizes the environmental factors, vegetation types and management practices. Conclusions: The results of this study contribute to a better understanding of allometric equations and an accurate estimate of AGB of Acacia woodlands in Ethiopia and similar ecosystems elsewhere. [ABSTRACT FROM AUTHOR]

Among the many other factors that would be taken as one of the most important options for climate change mitigation is forest wood carbon stock. Hence, the aim of this study was to examine the carbon stock potential of woody species and how it varies by community types and topographic aspects, along altitudinal and slope gradients in Sirso moist evergreen Afromontane vegetation ecosystem of southern Ethiopia. To collect data, a systematic sampling procedure was employed. Five transects were laid out across altitudinal gradients which aligned parallel at 2 km intervals, and 50 sample plots (20 m × 20 m) were laid along transects at 100 m altitudinal interval. Carbon stock was estimated based on the equations and conversion factors formulated for tropical forest carbon stock measurement. The results showed that the total carbon stock of woody species in Sirso moist evergreen Afromontane forest was 384.44 ton/ha. The carbon stock of woody species varied among community types, along altitudinal and slope gradients, while topographic aspect had no significant effect. The carbon stock was higher for the community type of Dracaena fragrans–Rytigynia neglecta, for mid-altitude (1934–2319 m.a.s.l.), and upper slope class (58–75%). Schefflera abyssinica, Syzygium guineense, and Ficus sur contributed 49% of the total carbon stock. Our study suggests that selecting a certain forest as the mitigation option for climate change needs to consider the determinants including vegetation composition and topographic features such as altitude and slope gradients. [ABSTRACT FROM AUTHOR]

Background: Sustainable land management interventions were introduced in Geda watershed in 2012 to reduce soil erosion, improve water infiltration, and increase plant-carbon inputs into the soil. This study explored the impact of the interventions on biomass production, carbon stock, and carbon sequestration. Stratified sampling was employed in the main and the dry seasons in the treated and untreated sub-watersheds that are found adjacent to each other. Above- and below-ground plant biomass, soil bulk density and organic carbon in 0–15- and 15–30-cm depths, and soil moisture content in 0–20- and 20–40-cm depths were collected from the crop, grazing, and tree lucerne plots. All analyses were performed based on standard procedures. Results: Plant biomass production, carbon stock, and carbon sequestration varied highly significantly (P ≤ 0.001) among sub-watersheds, landscape positions, and land uses. Higher mean values were observed for treated sub-watershed, lower landscape position, and tree lucerne plot. The higher mean values in the lower landscape position of the treated sub-watershed were due to tree lucerne plantation. Similarly, topsoil (0–15 cm) carbon stock was statistically higher (P ≤ 0.001) in the treated sub-watershed and at tree lucerne plot (P ≤ 0.05). In addition, carbon stock by sub-surface soil (15–30 cm) was significantly higher (P ≤ 0.001) in the treated sub-watershed under crop and grazing lands but the higher value was in cropland and in the upper position. This could be due to the decomposition of organic materials from biomasses of crops and biological supporting measures (tree lucerne and Phalaris) facilitated by tillage. Six years of sustainable land management interventions led to the sequestration of 12.25, 7.77, and 13.5 Mg C ha−1 under cropland, tree lucerne, and grazing plots, respectively. Conclusion: Sustainable land management interventions revealed auspicious ecological impacts in Geda watershed in terms of improving plant biomass production, carbon stock, and correspondingly capturing higher carbon dioxide equivalent taking untreated sub-watershed as a baseline. Prohibition of free grazing was the key element of the intervention to reduce biomass export and increase carbon sequestration in the treated sub-watershed. Thus, sustaining tree lucerne plants as a conservation measure and the prohibition of free grazing practices are principally essential. [ABSTRACT FROM AUTHOR]

Parkland agroforestry can store carbon and conserves biodiversity. Studying the relationship between carbon stock and biodiversity is crucial in understanding the tradeoff between major benefits of the parkland agroforestry system, and way to achieve the optimum balance between them. Therefore, this study aims to estimate the biomass and SOC in community type, and explore the relationship between carbon stocks and diversity. Tree with DBH (Diameter at breast height) > 2 cm was measured and species were identified in 75 (50x100m) randomly located plots. Species richness (S), Species evenness (J), Shannon-weiner diversity index (H') and Simpson diversity index (D) of the study area were 3.02, 0.81, 0.82 and 0.46 respectively. Similarly, the mean aboveground (AGC), belowground (BGC) and soil organic (SOC) carbon were 7.9, 3.03 and 20.07 Mg C ha-1 respectively. There was a liner and weakly significant correlation between AGC and tree J in plant community 2 (r = −0.558, P < 0.05) and 3 (r = −0.451, P < 0.05), and there was a negative correlation between J (r = −0.552, P < 0.05), D (r = −0.646, P < 0.05) and H' (r = −0.643, P < 0.05) with TC (Total carbon) in plant community 2. However, there was no significant relationship between J, D and H' with TC in plant communities 1 and 3. In these parkland agroforestry systems, the relationship tree species diversity with AGC and TC appeared to be highly variable; it indicates that parkland agroforestry systems have significantly improved the vegetation and SOC. However, forest carbon enhancement cannot assure the biodiversity conservation and promotion in a parkland agroforestry system. [ABSTRACT FROM AUTHOR]

Environmental gradients (altitude) are the factors that determine the carbon capturing the potential of a given forest. This study was conducted to determine the influence of elevation in the Yegof mountain forest's carbon sequestration potential. A total of 57 quadrats of 20 m by 20 m, 5 m by 5 m and 1 m by 1 m with nine horizontal transect lines were used for collecting the data on tree, shrub, and herbaceous and/or soil, respectively, in the three altitudinal gradients. The vegetation and soil data were analyzed statically in one-way analysis of variance using R software. Aboveground carbon (AGC) and belowground carbon (BGC) stocks were significantly higher (P < 0.001) in upper altitude (UA) gradient with 187.3 ± 27 ton ha−1 and 37.5 ± 5.4 ton ha−1, respectively, than other gradients. However, lower altitude (LA) has a significantly higher (P < 0.05) soil organic carbon (SOC) value than the other two altitudinal gradients with 266.07 ± 51.61 ton ha−1, followed by middle altitude (MA) with 194.55 ± 26.07 ton ha−1. Nevertheless, the overall carbon sock (TCS) was higher in MA (415.3 ton ha−1) with a slight difference from the UA (414.2ton ha−1). The study has found that environmental factors have a profound effect on carbon stocks, but the effect is not similar among the four carbon pools. Carbon stock value of Yegof mountain forest was highly affected by environmental factors such as altitude. Therefore, better ecological, policy and socioeconomic concerns should be adopted in the area especially in LA than the other gradients as it possesses the poorest performance of all in the majority of carbon pools. [ABSTRACT FROM AUTHOR]

This paper examined the potential of dry north western woodlands of Ethiopia (Adi Goshu, Lemlem Terara, and Gemed) for carbon stocks. Allometry equations were used to determine the aboveground, belowground, and dead woods biomasses; litter and herbaceous biomasses were determined using direct harvesting method. The result showed the estimated mean carbon stocks of the aboveground, belowground, and the dead wood biomass for the Untapped Boswellia Papyrifera Woodland (UW) in Lemlem Terara site were significantly higher (P < 0.05) than that of the Adi Goshu site. In the Gemed site, the mean Herb Biomass Carbon (HBC) stock was 1.2 Mg ha−1, which is significantly highest (P < 0.05) than the other two study sites (Lemlem Terara, 0.42 Mg ha−1 and Adi Goshu, 0.45 Mg ha−1) for the Tapped Boswellia Papyrifera Woodland (TW). In UW, the mean soil carbon stock of the Lemlem Terara site (58.19 Mg ha−1) was significantly (P < 0.05) higher than that of Adi Goshu (33.61 Mg ha−1). In the case of the total carbon stocks in UW stratum, for the Adi Goshu site, the carbon stock was estimated to be about 55.26 Mg ha−1 while 96.74 Mg ha−1 for Lemlem Terara. Therefore, Carbon stock in different carbon pools (aboveground and belowground biomass, dead wood, litter, herbaceous biomass, and soil) has a potential to decrease the rate of enrichment of atmospheric concentration of carbon dioxide. [ABSTRACT FROM AUTHOR]

Exclosures are used to regenerate native vegetation as a way to reduce soil erosion, increase rain water infiltration and provide fodder and woody biomass in degraded grazing lands. Therefore, this study assessed the impact of grazing exclosure on carbon sequestration and soil nutrients under 5 and 10 years of grazing exclosures and freely grazed areas in Tigray, northern Ethiopia. Carbon stocks and soil nutrients increased with increasing grazing exclusion. However, open grazing lands and 5 years of grazing exclosure did not differ in above‐ and belowground carbon stocks. Moreover, 10 years of grazing exclosure had a higher (p < 0.01) grass, herb and litter carbon stocks compared to 5 years exclosure and open grazing lands. The total carbon stock was higher for 10 years exclosure (75.65 t C ha‐1) than the 5 years exclosure (55.06 t C ha‐1) and in open grazing areas (51.98 t C ha‐1). Grazing lands closed for 10 years had a higher SOC, organic matter, total N, available P, and exchangeable K + and Na + compared to 5 year's exclosure and open grazing lands. Therefore, establishment of grazing exclosures had a positive effect in restoring degraded grazing lands, thus improving carbon sequestration potentials and soil nutrients. [ABSTRACT FROM AUTHOR]

Key message : Biomass equations are presented for five tree species growing in a natural forest in Ethiopia. Fitted models showed more accurate estimations than published generalized models for this dry tropical forest. Context : Biomass equations are needed to correctly quantify harvestable stock and biomass for sustainability efforts in forest management, but this kind of information is scarce in Ethiopia. Aims : This study sought to develop biomass models for five of the most common native tree species in the Chilimo dry afro-montane mixed forest in the central highlands of Ethiopia: Allophyllus abyssinicus, Olea europaea ssp . cuspidata, Olinia rochetiana, Rhus glutinosa, and Scolopia theifolia. Comparison with generalized models was intended to show the greater accuracy of the specific models. Methods : A total of 90 trees from different diameter classes were selected, felled, and divided into different biomass compartments. Biomass equation models were fitted using joint-generalized least squares regression to ensure the additivity property between the biomass compartments and total biomass. Results : These were the first models developed for these species in African tropical forests. Models were including diameter at breast height and total height as independent variables, obtaining more accurate biomass estimations using these models than from generalized models. Conclusion : Fitted models are reliable for estimating aboveground biomass in the Chilimo forest and for more general application in similar forest types. Model applicability for biomass or carbon estimation is high within forest inventory data contexts. [ABSTRACT FROM AUTHOR]

Miyo-Hadi watershed in the northeast dry highland of Ethiopia is known for the excessive degradation of natural resources and recurrent drought. To avert the problem soil and water conservation practices (SWCPs) were exhaustively implemented by governmental and non-governmental organizations based on the integrated watershed management approach. Although many studies have been conducted in the wet highlands of Ethiopia to assess the role of SWCPs on soil physical and chemical properties, carbon stock and grain yield, studies in the dry highlands of northeast Ethiopia are limited. Thus, this research is aimed to (i) investigate the impacts of SWCPs on soil physical and chemical properties, (ii) quantify the carbon stock trapped by the SWCPs, (iii) assess barley grain yield and (iv) evaluate farmers' perception on climate change adaptive strategies. Field experiment, observation, socio-economic survey were conducted for data collection. SPSS was used for data analysis. The result shows that soil and water conservation practices positively influenced the physico-chemical properties of the soil and barley grain yield. The quality of soil physico-chemical properties and barley grain yield in the treated farms/fields were better than the untreated farms. Similarly, the quality of soil physico-chemical properties and barley grain yield were found to be high in farms with lower slope gradients than the higher slope gradients. Almost all of the interviewed households (93%) perceived the existence of climate change in the area; and recurrent drought, pest and disease were among the events. About 65% of the households perceived that the implemented strategies (SWCPs, infrastructure, credit & saving, and capacity building) were helpful to adapt climate related shocks. Therefore, it can be concluded that integrated watershed management as a holistic approach, and SWCPs as specific technologies have meaningful roles in terms of minimizing land degradation, improving soil quality, increasing barley yield, and reducing climate change. • Three decades watershed intervention improved soil quality. • SOC was higher in field treated with biophysical SWCPs than physical practices alone. • About 93% of farmers perceived the existence of climate change. • Integrated watershed management can be a climate change adaptive strategy. [ABSTRACT FROM AUTHOR]