- Open Access
The effects of land cover change on carbon stock dynamics in a dry Afromontane forest in northern Ethiopia
© The Author(s) 2018
- Received: 24 April 2018
- Accepted: 29 August 2018
- Published: 6 September 2018
Forests play an important role in mitigating global climate change by capturing and sequestering atmospheric carbon. Quantitative estimation of the temporal and spatial pattern of carbon storage in forest ecosystems is critical for formulating forest management policies to combat climate change. This study explored the effects of land cover change on carbon stock dynamics in the Wujig Mahgo Waren forest, a dry Afromontane forest that covers an area of 17,000 ha in northern Ethiopia.
The total carbon stocks of the Wujig Mahgo Waren forest ecosystems estimated using a multi-disciplinary approach that combined remote sensing with a ground survey were 1951, 1999, and 1955 GgC in 1985, 2000 and 2016 years respectively. The mean carbon stocks in the dense forests, open forests, grasslands, cultivated lands and bare lands were estimated at 181.78 ± 27.06, 104.83 ± 12.35, 108.77 ± 6.77, 76.54 ± 7.84 and 83.11 ± 8.53 MgC ha−1 respectively. The aboveground vegetation parameters (tree density, DBH and height) explain 59% of the variance in soil organic carbon.
The obtained estimates of mean carbon stocks in ecosystems representing the major land cover types are of importance in the development of forest management plan aimed at enhancing mitigation potential of dry Afromontane forests in northern Ethiopia.
- Carbon dynamics
- Afromontane forest
- Land cover
Forest ecosystems are main sources of livelihood for many people and play a crucial role in the economic development of many countries [1, 2]. They are essential natural resources that furnish a wide-range of ecosystem services such as moderating atmospheric carbon balance and thus, climate change . Ecosystem services are the benefits that people get from ecosystem processes which are key to their survival and quality life. Some of these ecosystem services are food, carbon sequestration, nutrient cycling, air and water filtration, and flood amelioration . Carbon sequestration is the capture and storage of carbon that would somehow be produced and kept in the atmosphere or terrestrial systems . Terrestrial systems especially plants represent an important carbon store, estimated globally at 638 Gt, of which 44% is present in plant biomass . Carbon stock varies across forest types. While an average of 303 ton carbon ha−1 is retained in tropical forests , 66 ton carbon ha−1 and 44 ton ha−1 are retained in temperate and boreal forests respectively .
Ecosystem conditions affect carbon sequestration. Changes in land use including forest clearance for agriculture, settlement and industrial expansion have contributed about 136 (± 55) Gt carbon or one-third of total anthropogenic emissions of carbon dioxide (CO2) to the atmosphere over the past 150 years [9, 10]. Carbon emissions from deforestation and forest degradation are the second largest source of anthropogenic carbon emissions [11, 12]. Studies indicate that land cover change has significant effects on carbon stock. For instance, land cover change significantly affected carbon stock by impacting the aboveground biomass and soil organic carbon in Malagasy rainforest, Madagascar . On the other hand, changes in land cover from non-forest to forest ecosystems through exclosure, afforestation and reforestation activities are known to increase the carbon sequestration potential of an area. For example, Mekuria et al.  found that the introduction of exclosures on degraded free grazing lands increased carbon stocks in the lowlands of Tigray, Ethiopia. Similarly, Cui et al.  indicated that total carbon storage of forest ecosystems increased by approximately 29.3%, from 611.72 Tg in 1993 to 790.75 Tg in 2008, as a result of ecological restoration projects in Shaanxi, Northwest China.
Reducing carbon emissions is of great importance in this era of climate change. Various mechanisms have been proposed by the United Nations Framework Convention on Climate Change (UNFCCC). These include cutting down CO2 emissions from Annex 1 countries, and reducing emissions from deforestation and degradation by promoting conservation, sustainable management of forests and enhancing forest carbon stocks (REDD+) . The purpose of REDD+ is to create an incentive for developing countries to protect, better manage and wisely use their forest resources, thereby contributing to the global fight against climate change . One critical element for the REDD+ mechanism is the ability to know the carbon storage potential of a forest ecosystem, and the factors likely to affect both the rate of carbon accumulation and the maximum amount of carbon that can be stored.
REDD+ initiatives have focused on tropical moist forests because of their large carbon stocks per unit area  and the substantial emissions of greenhouse gases that would result from converting these forests to pastures, croplands, or commercial timber plantations. Little attention has been paid to the potential for carbon storage and reduction of emissions in the dry forests and woodlands [19–21].
Globally, dry forests cover about 42% of all intra-tropical vegetation . Most of the dry forest ecosystems found in Africa and the world’s tropical islands account for 70–80% of forested areas . Afromontane vegetation cover more than 50% of the land area of the highlands in Ethiopia of which the dry Afromontane forests form the largest part . The Wujig Mahgo Waren state forest is one of the dry Afromontane forests in Ethiopia . The dry Afromontane forests are composed of a number of indigenous tree species dominated by an association of Juniperus-Podocarpus or only Podocarpus species. The forests also contain broad-leaved species such as Dodonaea angustifolia, Carissa spinarum and Solanum schimperianum [26, 27].
The dry Afromontane forests provide a range of ecosystem services including provision of diverse habitats for fauna and fodder for livestock, watershed protection including groundwater regulation, flood control, soil erosion prevention and control, non-timber forest products and climate change mitigation [28–30]. The dry Afromontane forests have not been managed sustainably, and have undergone gradual degradation by human activities over a period of time . However, the Wujig Mahgo Waren forest is one of the remnants of the dry Afromontane forests in northern Ethiopia that continues to provide essential services for the livelihood of the people.
Estimation of changes in ecosystem services, especially carbon stock, due to changes in forest cover have not been of research interest despite its global importance in the face of climate change and REDD+ implementation. Hence, the study (i) quantified carbon stock in different land cover types; (ii) compared the contribution of different carbon pools in different land cover types; (iii) estimated the change in carbon stocks due to forest cover change for the last 30 years; and (iv) evaluated the functional relationship between soil organic carbon stock and aboveground vegetation properties.
Description of land cover classes used for analysis of change between 1985, 2000 and 2016
Land cover type
All lands with tree cover of canopy density over 40% 
All lands with tree cover (including mangrove cover) of canopy density between 10 and 40% 
Areas of land prepared for growing agricultural crops. This category includes areas currently under crop and land under preparation
Areas with little or no “green” vegetation present due to erosion, overgrazing and crop cultivation
Lands covered by herbaceous plants with coverage greater than 5% and land mixed rangeland with the coverage of shrub canopies less than 10% . Among the herbaceous species, Cynodon dactylon and Pennisetum petiolar had greater frequencies in the study area
Vegetation, litter and soil sampling
The vegetation, litter and soil samples of the forest were quantified using a systematic sampling design. Ten parallel line transects with 1 km distance were laid throughout the forest. Randomly selected 20 m × 20 m sample plots (main plots) were demarcated for trees and shrub assessment, and five 1 m × 1 m subplots within the main plot designated for litter and soil sampling. There were 88 sample plots set at 400 m intervals along transects.
All trees and shrubs were identified in the plots. A botanist supported by the local people was engaged to confirm scientific names and local names of the plant species. Diameter at breast height (DBH) and height (H) of all trees and shrubs with DBH ≥ 2 cm were measured using measuring tape and a 5 m pole graduated with 10 cm markings respectively from each main plot. Trees taller than 5 m were measured using clinometer positioned at 10 m distance from the base of the tree and focused on the highest point of the tree. Litter samples were collected from five 1 m × 1 m subplot within the main plot. A composite sample of 100 g was placed in a plastic bag and taken to the laboratory for litter carbon analysis.
Soil samples were collected from five subplots within main plot at a depth of 30 cm using a core sampler. All samples were placed in paper bags with appropriate labels. A composite sample of 100 g from each plot was submitted to analyze bulk density and soil organic carbon.
Land cover data
Area and proportion of land cover (LC) in Wujig Mahgo Waren forest in 1985, 2000, and 2016
Land cover distribution
Biomass carbon stock assessment
Allometric equations used for aboveground biomass calculation
AGB = 1.12 × DBH1.54
AGB = 0.55 × DBH1.89
Ln totWt = 2.11 + 2.19 × LnDSH
Y = 63.07 × DSH1.78
Y = 45.80 × DSH2.26
Other shrub sps.
Y = (0.3197 × DSH) + (0.0383 × DSH2.6)
Litter carbon estimation
Percentage of carbon is the carbon fraction of IPCC with a default value of 0.37.
Soil carbon stock assessment
Total carbon stock
Mapping of carbon stock by exponential semivariogram model was done to estimate spatial distribution of carbon values .
Soil texture analysis
Soil texture analysis was performed using the hydrometer method.
The SAS 9.0 was used to perform one-way analysis of variance (ANOVA) to test for mean differences of vegetation parameters, carbon stock means across land covers and carbon pools. Tukey HSD test was performed to separate means.
The Minitab computer statistical software was used to perform multiple linear regression analyses on soil organic carbon stock, biomass carbon stock, average tree diameter, and average tree height and tree density. The stepwise multiple regression with backward and forward selection techniques was used to select predictor variables.
Average (± standard error) woody plant dendrometric variables and average number of stems under different land cover types
Land cover type
# of stems ha−1
7.21 ± 0.51a
4.3 ± 0.44a
1618.3 ± 93.4a
5.56 ± 0.47b
3.03 ± 0.21b
959.1 ± 64.9b
2.96 ± 0.17c
1.89 ± 0.10b
196.9 ± 19.7c
Average (± standard error) soil properties (0–30 cm) of different land uses in the Wujig Mahgo Waren forest of Ethiopia
Particle size distribution
BD (g cm−3)
33.1 ± 3.3ab
34.5 ± 2.9a
32.3 ± 2.3a
3.1 ± 0.17a
1.11 ± 0.05a
27.2 ± 2.6ab
43.8 ± 2.2a
28.0 ± 1.6a
2.7 ± 0.16a
1.17 ± 0.04a
29.2 ± 8.1ab
42.5 ± 7.1a
28.3 ± 2.6a
2.8 ± 0.27a
1.28 ± 0.07a
19.7 ± 3.6b
48.4 ± 4.4a
31.8 ± 3.2a
2.2 ± 0.33a
1.31 ± 0.04a
50.2 ± 11.1a
27.8 ± 8.0a
22.0 ± 6.0a
2.0 ± 0.25a
1.37 ± 0.05a
Estimated carbon stocks (Mg ha−1) across the land cover types
C contents of
65.81 ± 18.50a
12.67 ± 2.22b
3.43 ± 0.33b
11.38 ± 2.61a
2.92 ± 0.41b
1.02 ± 0.08b
2.25 ± 0.27a
1.68 ± 0.20ab
1.17 ± 0.09b
102.33 ± 13.2a
87.55 ± 12.73a
103.13 ± 6.75a
76.54 ± 7.84a
83.13 ± 8.53a
181.78 ± 27.1a
104.83 ± 12.35b
108.77 ± 6.77b
76.54 ± 7.84b
83.11 ± 8.53b
The carbon content of litter biomass was significantly higher under dense forest than grassland (Table 6). The mean litter carbon was high in open forest as compared to grassland. Soil organic carbon was higher in grassland and the lowest mean soil organic carbon was recorded in cultivated land (Table 6). The conversion of dense forests to cultivated land resulted in a 25% reduction in soil organic carbon stock.
Contribution of carbon pools
Carbon stocks (Mg ha−1) in different carbon pools in Wujig Mahgo Waren forest
65.81 ± 18.50a
11.38 ± 2.61b
102.33 ± 13.19a
2.25 ± 0.27b
12.67 ± 2.22b
2.92 ± 0.41b
87.55 ± 12.73a
1.68 ± 0.20b
3.43 ± 0.33b
1.02 ± 0.08b
103.13 ± 6.75a
1.17 ± 0.09b
Effect of land cover change on carbon stocks
Total carbon stock (Gg) for Wujig Mahgo Waren forest in the year 1985, 2000 and 2016
Land cover types
Carbon stocks (Gg)
Carbon stock changes (Gg)
Relationship between soil organic carbon (SOC) stock and aboveground vegetation properties
Correlations between SOC stock and vegetation parameters
Pearson correlation coefficient values of soil organic carbon, DBH, height and tree density
Regression models of soil organic carbon stock
Regression model of soil organic carbon stock in Wujig Mahgo Waren forest
Effects of land cover change on carbon stock
The study showed how carbon stocks in vegetation, litter and soils were varied across land cover types and different periods. Dense forests had higher biomass carbon stock compared to open forests and that of the grassland. Rajput et al.  and Solomon et al.  found higher biomass carbon in forest ecosystems as compared to other land cover types in northwestern Himalaya and northern Ethiopia, respectively. The substantial variation in biomass carbon across the land cover types might be due to the variation in the number of stems, density and the size of the trees in each land cover type. This is in line with the result of Solomon et al.  which stated that tree density and diameter have an effect on biomass carbon in northern Ethiopia. Moreover, the low biomass carbon recorded in grasslands was caused by overgrazing practices and human intrusion that influenced the recovery and growth of herbaceous plant species and adversely smothers tree and shrub growth . This assertion is supported by the study conducted by Mekuria and Yami  who suggested that free grazing affects vegetation composition and growth of herbaceous plant species in the drylands of northern Ethiopia.
The biomass carbon estimates of the dense forests were within the global range, from 20 to 150 Mg ha−1 for semiarid tropics as reported by Tiessen et al. . The results were also within the range of tropical dry forests’ carbon stock  which was between 50 and 350 t ha−1. However, the average biomass carbon stock of Wujig Mahgo Waren forest was lower than the Egdu forest  which was 337 t ha−1 found in similar agroecology. The biomass carbon stock of the present study was fairly small compared to the biomass carbon stocks in the moist Bale forest in Ethiopia . On the other hand, the biomass carbon stock in the current study was fairly higher compared to Solomon et al.  who reported 58.11 Mg ha−1 in the managed forest of Tigray, northern Ethiopia. As compared to the present study, Chinasho et al.  found lower carbon stock with 45.23 t ha−1 in woody plants of Humbo forest, southern Ethiopia. The variability in biophysical characteristics such as climate, soil and vegetation type might contribute to the difference in biomass carbon stock across the different forests.
The carbon content of litter biomass was significantly higher under dense forests than grasslands. The difference in litter carbon among the land cover types might be due to the variations in vegetation cover. This was confirmed by the study of Descheemaeker et al.  who stated that litter accumulation rely upon vegetation cover and is affected by soil fertility in exclosures of the Tigray highlands, Ethiopia. The estimated litter carbon of the present study is in accordance with findings reported by Ordóñez et al. , who found between 0.6 and 4.1 Mg ha−1 of litter carbon in montane forests of central and southern Mexico. However, the estimated value of litter carbon in the present study was higher than that reported by Aman  who found 1.38 t ha−1 litter carbon in dry evergreen montane forests of the Bale mountain national park, Ethiopia. Conversely, compared to the litter carbon stocks of Chilimo forest (9.36 Mg ha−1) per Tesfaye et al.’s  observation, the current result was very low.
There was higher soil organic carbon stock in grassland and dense forest as compared to open forest, bare land and cultivated land. The differences recorded in soil organic carbon between land cover types were not significant. In agreement with the present study, Haghdoost et al.  showed that no significant difference existed in the average total soil carbon stock among land cover types in Noor county, Iran, though higher soil carbon was found in forests as compared to cultivated lands. Ordóñez et al.  also found no significant difference in average total soil carbon in the central highlands of Michoacan, Mexico. The higher mean soil organic carbon stock in grassland compared with the other land uses could be due to higher annual turnover of organic matter from dying grassroots. This notion was supported by the report of Guo and Gifford , who stated that grassroots decompose faster than tree roots and hence contribute higher organic matter to soils. The higher soil organic carbon stock recorded in the dense forest was mainly because of the biomass inputs and low rate of litter decay. Tesfaye et al.  also found a higher mean carbon stock in natural forest than in all the other land cover categories in Chilimo, a dry Afromontane forest in Ethiopia. The lower soil organic carbon recorded in the cultivated land might be due to the low input of organic matter being returned to the soil and high rates of oxidation of soil organic matter by tillage .
The high carbon content of the soils in the different land cover types was consistent with a previous study by Lemenih and Itanna  who studied soil carbon stock for the upper 60 cm depth of soil in southern Ethiopia. The result of this study were also within the ranges of values for tropical soils of 86 Mg carbon ha−1 , 113 Mg carbon ha−1  and 72.8–116.4 Mg carbon ha−1 of montane forests of Central Highlands of Michoacan, Mexico . Contrary to the results of this current study, Feyissa et al.  found higher soil organic carbon in Egdu Forest, Ethiopia. On the other hand, higher soil organic carbon stock was recorded under the present study as compared to the results reported by Girmay and Singh  for Maileba and Gum Selassa sites of northern Ethiopia.
Land cover change can change soil carbon stock. The results indicated that alteration of dense forests to cultivated land brought about 25% reductions in soil organic carbon stock. Girmay et al.  who reviewed carbon stock in top soils (0–10 cm) of Ethiopia, found that conversion of native forest into croplands and plantations reduced carbon stock by up to 63% and 83%, respectively.
Generally, dense forest had higher total carbon stock followed by open forest, grassland, cultivated land and bare land in this study. The average total carbon stock of the dense forest was 181.8 Mg ha−1, which was higher than that reported by Mekuria  for exclosures on communal grazing lands in Ethiopia. Similarly, the results were slightly higher than that reported by Andriamananjara et al.  for the Malagasy rainforest in eastern Madagascar. The carbon stock in the present study was lower than the carbon stock for Northwestern Himalaya , for Egdu forest , for montane forests of central and southern Mexico  and for low land area of Simien mountains national park . The variations in total carbon stock among the different studies might be due to variation in forest composition, soil and other biophysical factors.
In this study, the four carbon pools contributed differently to the five land cover classes. Higher levels of carbon were stored in the soil pool rather than the vegetation biomass and litter carbon of all land cover types. Most of the carbon stocks in grassland, cultivated land and bare land were mainly found in the soil. For example, in grassland, a large percentage (> 90%) of the total carbon was stored in the soil. This was in accordance with the investigation of Chen et al. , where the total carbon stock of the savanna was 204 ± 53 Mg ha−1, with 84% below ground and 16% above ground carbon stock. According to Scurlock and Hall , soil carbon can store over 75% of the global carbon found in terrestrial ecosystems. Mekuria  also found higher carbon stock in soil than other carbon pools for exclosures on communal grazing lands in Ethiopia. However, contrary to the findings of this present study, Girardin et al.  and Lü et al.  found higher carbon stored in biomass followed by soil and litter in tropical forests.
In the present study, the change in carbon stock caused by change in land cover type was assessed using the area of each land cover type and their corresponding carbon stock values. The study revealed an increase in carbon stock between 1985 and 2000 and a decrease between 2000 and 2016. The change in forest management approach and strategies contributed to the changes of the carbon stock overtime. In 1991, there was a change in natural resource management approach from state forest management to participatory forest management that included intensive soil and water conservation, exclosure establishment and community participation which gave the forest a recovery time for which some improvements in carbon stock have been observed between 1985 and 2000 . Forest expansion and growth increase carbon stock. This was confirmed by a study of Fang et al.  who stated carbon storage increased significantly after the late 1970s from 4.38 to 4.75 Pg of carbon by 1998, mainly due to forest expansion and regrowth in China. Silver et al.  also indicated that reforestation of abandoned tropical agricultural and pasturelands has the potential to serve as a carbon offset mechanism both above and belowground for at least 40–80 years, and possibly much longer.
However, between 2000 and 2016 a reduction in total carbon stock was recorded due to loss of forest cover caused by encroachment of communities on lands to get wood for fuel, construction materials, more arable land and animal feed. Forestland is a collection of native tree species that has been in existence for quite a long time with many understory vegetation. However, grassland is mainly composed of shrub species with low biomass and total carbon stock as compared to the forest. Consequently, the change from forest to grassland and cultivated land significantly affects total carbon stocks. Our study illustrated that total carbon stock was affected by the land cover change in Wujig Mahgo Waren forest.
In agreement with the present study, previous studies have shown that land cover change is a key factor in carbon stock changes. For example, Shrestha et al.  observed a net gain in carbon stock in the larger parts of the mountain watershed in Nepal from 1976 to 1989, while a net loss was recorded in the period between 1989 and 2003. Kashaigili and Majaliwa  also realized a reduction in carbon stock from the year 1980 to 2010 in two forests of Tanzania due to forest cover change. Similarly, Gond et al.  also reported a 30% loss in carbon stock from 1984 to 2012 in wood-fuel supply basin of Kinshasa. Furthermore, Gaston et al.  showcased a loss in above ground carbon stock by 6.6 Pg due to forest degradation in tropical Africa between 1980 and 1990. In the same period , recorded 30 Tg loss of above ground carbon due to deforestation and degradation in Ethiopia. A study by Zhang et al.  in China showed that carbon stock reduced by 60 Tg between 1995 and 2010 due to land cover change.
Linkage between soil organic carbon stock and above ground vegetation properties
Various studies have shown that vegetation variability determines topsoil carbon variability in the Savanna and woodland ecosystems [76–78]. In the present study, soil organic carbon and above ground vegetation properties had a positive link, showing that vegetation parameters do appear to be predictors of soil organic carbon stock. Moreover, above ground vegetation parameters such as tree density, DBH and height explained 59% of the variance in soil organic carbon. In a similar study by Li et al.  above ground vegetation parameters such as tree height, above ground biomass and tree density elucidated 80% of the variance in soil organic carbon in cold-temperate mountainous forests of Japan. Dar and Sundarapandian  also indicated that above ground vegetation properties are common predictors to estimate soil organic carbon stock in complex mountainous forests across different spatial scales. Furthermore, Woollen et al.  found the strongest correlation between soil carbon and large tree above ground carbon stocks with 24% of soil carbon variability explained by above ground carbon stock. A study by Kurgat et al.  showed that vegetation cover explained 89% of the variability in soil organic carbon in the rangelands of northern Kenya. Similarly, a study by Liu et al.  in the Qinghai–Tibetan Plateau China showed a significant correlation between above ground biomass and soil organic carbon. Contrary to this present study, Zhang et al.  found that plant biomass, woody plant density and tree height did not emerge as significant predictor variables for soil organic carbon in the subalpine coniferous forest in Southwest China. Mathew et al.  also found a poor correlation between soil organic carbon stock and above ground carbon in Mount Kilimanjaro, Tanzania. The inconsistency between these studies shows that environmental factors affecting the distributions of vegetation and soil carbon stocks are site-specific.
Findings from this study show that vegetation parameters can be valuable when predicting soil organic carbon stock in the dry Afromontane forests. This is vital for estimating soil carbon stock, particularly in inaccessible landscapes, as above ground vegetation properties are moderately simple to assess and can be quickly surveyed through remote sensing methods.
The present study discussed the variation in carbon stock when forest cover changes. There was high variability in total carbon stocks among land cover types with high carbon stocks observed in dense forest and low carbon stocks in cultivated land and bare land. Open forest and grassland sites showed intermediate carbon stock values. However, soil organic carbon did not show significant differences among land cover types. Significantly highest carbon stock was observed in soil carbon pools as compared to the carbon in biomass and litter carbon pools in all land use and land cover types. Land cover change has an impact on carbon stock, with carbon stock slightly increasing between 1985 and 2000, and decreasing from 2000 to 2016. Furthermore, there was a significant correlation between aboveground vegetation properties and soil organic carbon. The aboveground vegetation properties could be useful in the estimation of the soil organic carbon stock in the dry Afromontane forests. Our study indicates that, dry Afromontane forests have the potential to store large amounts of carbon in its biomass and soil. Therefore, management opportunities for increasing biomass can be beneficial for climate mitigation. Furthermore, in this study we tried to analyze the effect of land cover change on carbon stock, however further studies should be conducted on the effect of other biophysical factors on carbon stock.
NS conceived and designed the study; NS collected and analyzed the data and wrote the paper; EB, OP, TA and IKA critically reviewed the paper and provided comments on the contents and structure of the paper. All authors read and approved the final manuscript.
We thank the University of Ghana and Transdisciplinary Training for Resource Efficiency and Climate Change Adaptation in Africa II (TRECCAfrica II) project. We also acknowledge Angesom Shushay and farmers of Wujig Mahgo Waren for their assistance during the fieldwork activities. We are grateful to the two anonymous referees for constructive comments on an earlier version of this manuscript.
The authors declare that they have no competing interests.
Availability of data and materials
Data are presented as additional file.
Consent for publication
All co-authors have consented to publication.
Ethics approval and consent to participate
This study was financed by Mekelle University (CRPO/CoDANR/PhD/001/09) and the Steps Toward Sustainable Forest Management with the Local Communities in Tigray, northern Ethiopia (ETH 13/0018) funded by NORAD/NORHED.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
- Agrawal A, Cashore B, Hardin R, Shepherd G, Benson C, Miller D. Economic contributions of forests. Istanbul: Turkey United Nations; 2013.Google Scholar
- Chao S. Forest peoples: numbers across the world. Moreton-in-Marsh: Forest Peoples Programme Moreton-in-Marsh; 2012.Google Scholar
- Kumar R, Nandy S, Agarwal R, Kushwaha SPS. Forest cover dynamics analysis and prediction modeling using logistic regression model. Ecol Indic. 2014;45:444–55.View ArticleGoogle Scholar
- Costanza R, d’Arge R, De Groot R, Faber S, Grasso M, Hannon B, et al. The value of the world’s ecosystem services and natural capital. Nature. 1997;387:253–60.View ArticleGoogle Scholar
- Herzog H, Golomb D. Carbon capture and storage from fossil fuel use. Encycl Energy. 2004;1:277–87.Google Scholar
- FAO. Global forest resources assessment 2015: How are the world’s forests changing?. Rome: Food and Agriculture Organization of the United Nation; 2015. p. 2015.Google Scholar
- Lü X-T, Yin J-X, Jepsen MR, Tang J-W. Ecosystem carbon storage and partitioning in a tropical seasonal forest in Southwestern China. For Ecol Manag. 2010;260(10):1798–803.View ArticleGoogle Scholar
- Thurner M, Beer C, Santoro M, Carvalhais N, Wutzler T, Schepaschenko D, et al. Carbon stock and density of northern boreal and temperate forests. Glob Ecol Biogeogr. 2014;23(3):297–310.View ArticleGoogle Scholar
- Watson RT, Noble IR, Bolin B, Ravindranath N, Verardo DJ, Dokken DJ. Land use, land-use change and forestry. A special report of the intergovernmental panel on climate change (IPCC). Cambridge: Cambridge University; 2000.Google Scholar
- Gómez DR, Watterson JD, Americano BB, Ha C, Marland G, Matsika E, et al. IPCC guidelines for national greenhouse gas inventories. Hayama: Institute for Global Environmental Strategies; 2006.Google Scholar
- Le Quere C, Raupach MR, Canadell JG, Marland G. Trends in the sources and sinks of carbon dioxide. Nat Geosci. 2009;2(12):831–6.View ArticleGoogle Scholar
- van der Werf GR, Morton DC, DeFries RS, Olivier JGJ, Kasibhatla PS, Jackson RB, et al. CO2 emissions from forest loss. Nat Geosci. 2009;2(11):737–8.View ArticleGoogle Scholar
- Andriamananjara A, Hewson J, Razakamanarivo H, Andrisoa RH, Ranaivoson N, Ramboatiana N, et al. Land cover impacts on aboveground and soil carbon stocks in Malagasy rainforest. Agric Ecosyst Environ. 2016;233(Supplement C):1–15.View ArticleGoogle Scholar
- Mekuria W, Veldkamp E, Haile M, editors. Carbon stock changes with relation to land use conversion in the lowlands of Tigray, Ethiopia. In: Proceedings of Conference on International Research on Food Security, Natural Resource Management and Rural Development; Proceedings of the 36th Meeting of the Italian Society of Agronomy. 2009.Google Scholar
- Cui G, Chen Y, Cao Y. Temporal-spatial pattern of carbon stocks in forest ecosystems in Shaanxi, Northwest China. PLoS ONE. 2015;10(9):e0137452.View ArticleGoogle Scholar
- Kashaigili JJ, Majaliwa AM. Integrated assessment of land use and cover changes in the Malagarasi river catchment in Tanzania. Phys Chem Earth. 2010;35(13):730–41.View ArticleGoogle Scholar
- Sandker M, Nyame SK, Förster J, Collier N, Shepherd G, Yeboah D, et al. REDD payments as incentive for reducing forest loss. Conserv Lett. 2010;3(2):114–21.View ArticleGoogle Scholar
- MEA. Ecosystems and human well-being: biodiversity Synthesis. Washington, DC: Island Press; 2005.Google Scholar
- Chidumayo E, Marunda C. Dry forests and woodlands in sub-Saharan Africa: context and challenges. In: Chidumayo EN, Gumbo DJ, editors. The dry forests and woodlands of Africa: managing for products and services. 2010. p. 1–10.Google Scholar
- Day M, Gumbo D, Moombe KB, Wijaya A, Sunderland T. Zambia Country Profile: monitoring, reporting and verification for REDD+. Bogor: CIFOR; 2014.Google Scholar
- SÁNchez-Azofeifa GA, Kalacska M, Quesada M, Calvo-Alvarado JC, Nassar JM, RodrÍGuez JP. Need for integrated research for a sustainable future in tropical dry forests. Conserv Biol. 2005;19(2):285–6.View ArticleGoogle Scholar
- Bullock SH, editor. Seasonally dry tropical forests. Cambridge: Cambridge Univ. Press; 1995.Google Scholar
- Murphy PG, Lugo AE. Ecology of tropical dry forest. Annu Rev Ecol Syst. 1986;17(1):67–88.View ArticleGoogle Scholar
- Teketay D. Seed ecology and regeneration in dry Afromontane forests of Ethiopia. Umeå: Swedish University of Agricultural Sciences; 1996.Google Scholar
- GIZ. Land use land cover mapping of PFM project areas and adjacent SLMP watersheds in three regions of Ethiopia. Mekelle: Mekelle University; 2015.Google Scholar
- Wubet T, Kottke I, Teketay D, Oberwinkler F. Mycorrhizal status of indigenous trees in dry Afromontane forests of Ethiopia. For Ecol Manag. 2003;179(1–3):387–99.View ArticleGoogle Scholar
- Tesema AB, Ann B, Bo T. Useful trees and shrubs for Ethiopia: identification, propagation and management for agricultural and pastoral communities. 1993.Google Scholar
- Asfaw A, Lemenih M, Kassa H, Ewnetu Z. Importance, determinants and gender dimensions of forest income in eastern highlands of Ethiopia: the case of communities around Jelo Afromontane forest. For Policy Econ. 2013;28:1–7.View ArticleGoogle Scholar
- Solomon N, Birhane E, Tadesse T, Treydte AC, Meles K. Carbon stocks and sequestration potential of dry forests under community management in Tigray, Ethiopia. Ecol Process. 2017;6(1):20.View ArticleGoogle Scholar
- Price M, Gratzer G, Alemayehu Duguma L, Kohler T, Maselli D. Mountain forests in a changing world: realizing values, addressing challenges. Rome: Food and Agriculture Organization of the United Nations (FAO) and Swiss Agency for Development and Cooperation (SDC); 2011.Google Scholar
- Tesfaye G, Teketay D, Fetene M, Beck E. Regeneration of seven indigenous tree species in a dry Afromontane forest, southern Ethiopia. Flora. 2010;205(2):135–43.View ArticleGoogle Scholar
- Amanuel Z, Girmay G, Atkilt G. Characterisation of agricultural soils in Cascape intervention woredas in southern Tigray, Ethiopia. Mekelle: Mekelle University; 2015.Google Scholar
- Solomon N, Hishe H, Annang T, Pabi O, Asante I, Birhane E. Forest cover change, key drivers and community perception in Wujig Mahgo Waren forest of northern Ethiopia. Land. 2018;7(1):32.View ArticleGoogle Scholar
- Singh J, Dhillon SS. Agricultural geography. New Delhi: Tata McGraw-Hill; 2004.Google Scholar
- Deng X, Huang J, Rozelle S, Uchida E. Cultivated land conversion and potential agricultural productivity in China. Land Use Policy. 2006;23(4):372–84.View ArticleGoogle Scholar
- Pearson T, Walker S, Brown S. Sourcebook for land use, land-use change and forestry projects. Arlington: Winrock International and the Bio-carbon fund of the World Bank; 2005.Google Scholar
- Chave J, Réjou-Méchain M, Búrquez A, Chidumayo E, Colgan MS, Delitti WBC, et al. Improved allometric models to estimate the aboveground biomass of tropical trees. Glob Change Biol. 2014;20(10):3177–90.View ArticleGoogle Scholar
- Cairns AM, Brown S, Helmer HE, Baumgardner AG. Root biomass allocation in the world’s upland forests. Oecologia. 1977;111(1):1–11.View ArticleGoogle Scholar
- Ubuy MH, Gebrehiwot K, Raj AJ. Biomass estimation of exclosure in the Debrekidan watershed, Tigray region, northern Ethiopia. Int J Agric For. 2014;4(2):88–93.Google Scholar
- Cleemput S, Muys B, Kleinn C, Janssens MJ. Biomass estimation techniques for enclosures in a semi-arid area: a case study in Northern Ethiopia. University of Göttingen, Germany [www document]. 2004. http://www.tropentag.de/2004/abstracts/full/3.pdf. Accessed 19 Dec 2017.
- WBISPP. Manual for woody biomass inventory. Addis Ababa: Woody Biomass Inventory and Strategic Planning Project, Ministry of Agriculture; 2000.Google Scholar
- Walkley A, Black IA. An examination of the degtjareff method for determining soil organic matter, and a proposed modification of the chromic acid titration method. Soil Sci. 1934;37(1):29–38.View ArticleGoogle Scholar
- Gibbs HK, Brown S, Niles JO, Foley JA. Monitoring and estimating tropical forest carbon stocks: making REDD a reality. Environ Res Lett. 2007;2(4):045023.View ArticleGoogle Scholar
- Gaston G, Brown S, Lorenzini M, Singh KD. State and change in carbon pools in the forests of tropical Africa. Glob Change Biol. 1998;4(1):97–114.View ArticleGoogle Scholar
- Kashaigili J, Mdemu M, Nduganda A, Mbilinyi B. Integrated assessment of forest cover change and above-ground carbon stock in Pugu and Kazimzumbwi forest reserves, Tanzania. Adv Remote Sens. 2013;2(1):9.Google Scholar
- Du H, Zhou G, Fan W, Ge H, Xu X, Shi Y, et al. Spatial heterogeneity and carbon contribution of aboveground biomass of moso bamboo by using geostatistical theory. Plant Ecol. 2010;207(1):131–9.View ArticleGoogle Scholar
- Rajput BS, Bhardwaj DR, Pala NA. Factors influencing biomass and carbon storage potential of different land use systems along an elevational gradient in temperate northwestern Himalaya. Agrofor Syst. 2017;91(3):479–86.View ArticleGoogle Scholar
- Mekuria W, Yami M. Changes in woody species composition following establishing exclosures on grazing lands in the lowlands of northern Ethiopia. Afr J Environ Sci Technol. 2013;7(1):30–40.Google Scholar
- Tiessen H, Feller C, Sampaio EVSB, Garin P. Carbon sequestration and turnover in semiarid Savannas and dry forest. Clim Change. 1998;40(1):105–17.View ArticleGoogle Scholar
- Cavanaugh KC, Gosnell JS, Davis SL, Ahumada J, Boundja P, Clark DB, et al. Carbon storage in tropical forests correlates with taxonomic diversity and functional dominance on a global scale. Glob Ecol Biogeogr. 2014;23(5):563–73.View ArticleGoogle Scholar
- Feyissa A, Soromessa T, Argaw M. Forest carbon stocks and variations along altitudinal gradients in Egdu forest: implications of managing forests for climate change mitigation. Sci Technol Arts Res J. 2013;2(4):40–6.View ArticleGoogle Scholar
- Watson C, Mourato S, Milner-Gulland EJ. Uncertain emission reductions from forest conservation: REDD in the Bale Mountains, Ethiopia. Ecol Soc. 2013;18(3):6.View ArticleGoogle Scholar
- Chinasho A, Soromessa T, Bayable E. Carbon stock in woody plants of Humbo forest and its variation along altitudinal gradients: the case of Humbo district, Wolaita zone, southern Ethiopia. Int J Environ Prot Policy. 2015;3(4):97–103.View ArticleGoogle Scholar
- Descheemaeker K, Muys B, Nyssen J, Poesen J, Raes D, Haile M, et al. Litter production and organic matter accumulation in exclosures of the Tigray highlands, Ethiopia. For Ecol Manag. 2006;233(1):21–35.View ArticleGoogle Scholar
- Ordóñez JAB, de Jong BHJ, García-Oliva F, Aviña FL, Pérez JV, Guerrero G, et al. Carbon content in vegetation, litter, and soil under 10 different land-use and land-cover classes in the central highlands of Michoacan, Mexico. For Ecol Manag. 2008;255(7):2074–84.View ArticleGoogle Scholar
- Aman H. Estimation of carbon stock in dry evergreen montane forest and its role in climate change mitigation: the case of Bale mountains national park, Ethiopia, Addis Ababa University. 2015.Google Scholar
- Tesfaye M, Bravo F, Ruiz-Peinado R, Pando V, Bravo-Oviedo A. Impact of changes in land use, species and elevation on soil organic carbon and total nitrogen in Ethiopian Central Highlands. Geoderma. 2016;261(Supplement C):70–9.View ArticleGoogle Scholar
- Haghdoost N, Akbarinia M, Hosseini SM. Land-use change and carbon stocks: a case study, Noor County, Iran. J For Res. 2013;24(3):461–9.View ArticleGoogle Scholar
- Guo LB, Gifford RM. Soil carbon stocks and land use change: a meta analysis. Glob Change Biol. 2002;8(4):345–60.View ArticleGoogle Scholar
- Dalal RC, Chan KY. Soil organic matter in rainfed cropping systems of the Australian cereal belt. Soil Res. 2001;39(3):435–64.View ArticleGoogle Scholar
- Lemenih M, Itanna F. Soil carbon stocks and turnovers in various vegetation types and arable lands along an elevation gradient in southern Ethiopia. Geoderma. 2004;123(1–2):177–88.View ArticleGoogle Scholar
- Brown S, Lugo AE. The storage and production of organic matter in tropical forests and their role in the global carbon cycle. Biotropica. 1982;14(3):161–87.View ArticleGoogle Scholar
- Post W, Emanuel W, Zinke P, Stangenberger A. Soil carbon pools and world life zones. Nature. 1982;298(5870):156–9.View ArticleGoogle Scholar
- Girmay G, Singh BR. Changes in soil organic carbon stocks and soil quality: land-use system effects in northern Ethiopia. Acta Agric Scand Sect B Soil Plant Sci. 2012;62(6):519–30.Google Scholar
- Girmay G, Singh BR, Mitiku H, Borresen T, Lal R. Carbon stocks in Ethiopian soils in relation to land use and soil management. Land Degrad Dev. 2008;19(4):351–67.View ArticleGoogle Scholar
- Mekuria W. Changes in regulating ecosystem services following establishing exclosures on communal grazing lands in Ethiopia: a synthesis. J Ecosyst. 2013;2013:12.View ArticleGoogle Scholar
- Simegn TY, Soromessa T, Bayable E. Forest carbon stocks in lowland area of Simien Mountains National Park: implication for climate change mitigation. Sci Technol Arts Res J. 2014;3(3):29–36.View ArticleGoogle Scholar
- Chen X, Hutley LB, Eamus D. Carbon balance of a tropical savanna of northern Australia. Oecologia. 2003;137(3):405–16.View ArticleGoogle Scholar
- Scurlock JMO, Hall DO. The global carbon sink: a grassland perspective. Glob Change Biol. 1998;4(2):229–33.View ArticleGoogle Scholar
- Girardin CAJ, Malhi Y, AragÃO LEOC, Mamani M, Huaraca Huasco W, Durand L, et al. Net primary productivity allocation and cycling of carbon along a tropical forest elevational transect in the Peruvian Andes. Glob Change Biol. 2010;16(12):3176–92.View ArticleGoogle Scholar
- Fang J, Chen A, Peng C, Zhao S, Ci L. Changes in forest biomass carbon storage in China between 1949 and 1998. Science. 2001;292(5525):2320–2.View ArticleGoogle Scholar
- Silver WL, Ostertag R, Lugo AE. The potential for carbon sequestration through reforestation of abandoned tropical agricultural and pasture lands. Restor Ecol. 2000;8(4):394–407.View ArticleGoogle Scholar
- Shrestha BM, Dick ØB, Singh B. Effects of land-use change on carbon dynamics assessed by multi-temporal satellite imagery in a mountain watershed of Nepal. Acta Agric Scand Sect B Soil Plant Sci. 2010;60(1):10–23.Google Scholar
- Gond V, Dubiez E, Boulogne M, Gigaud M, Peroches A, Pennec A, et al. Forest cover and carbon stock change dynamics in the Democratic Republic of Congo: case of the wood-fuel supply basin of Kinshasa. Bois et Forêts des Tropiques. 2016;327:19–28.View ArticleGoogle Scholar
- Zhang M, Huang X, Chuai X, Yang H, Lai L, Tan J. Impact of land use type conversion on carbon storage in terrestrial ecosystems of China: a spatial-temporal perspective. Sci Rep. 2015;5:10233.View ArticleGoogle Scholar
- Bird MI, Veenendaal EM, Moyo C, Lloyd J, Frost P. Effect of fire and soil texture on soil carbon in a sub-humid savanna (Matopos, Zimbabwe). Geoderma. 2000;94(1):71–90.View ArticleGoogle Scholar
- Rossi J, Govaerts A, De Vos B, Verbist B, Vervoort A, Poesen J, et al. Spatial structures of soil organic carbon in tropical forests—a case study of southeastern Tanzania. Catena. 2009;77(1):19–27.View ArticleGoogle Scholar
- Wang L, Okin GS, Caylor KK, Macko SA. Spatial heterogeneity and sources of soil carbon in southern African savannas. Geoderma. 2009;149(3):402–8.View ArticleGoogle Scholar
- Li P, Wang Q, Endo T, Zhao X, Kakubari Y. Soil organic carbon stock is closely related to aboveground vegetation properties in cold-temperate mountainous forests. Geoderma. 2010;154(3–4):407–15.View ArticleGoogle Scholar
- Dar J, Sundarapandian S. Soil organic carbon stock assessment in two temperate forest types of western Himalaya of Jammu and Kashmir, India. For Res. 2013;3(114):2.Google Scholar
- Woollen E, Ryan CM, Williams M. Carbon stocks in an African woodland landscape: spatial distributions and scales of variation. Ecosystems. 2012;15(5):804–18.View ArticleGoogle Scholar
- Kurgat BK, Golicha D, Giese M, Kuria SG, Asch F. Relationship between vegetation cover types and soil organic carbon in the rangelands of Northern Kenya. Livestock Res Rural Dev. 2014;26. http://www.lrrd.org/lrrd26/9/kurg26162.html. Retrieved 21 Oct 2017.
- Liu W, Chen S, Qin X, Baumann F, Scholten T, Zhou Z, et al. Storage, patterns, and control of soil organic carbon and nitrogen in the northeastern margin of the Qinghai–Tibetan Plateau. Environ Res Lett. 2012;7(3):035401.View ArticleGoogle Scholar
- Zhang Y, Duan B, Xian J, Korpelainen H, Li C. Links between plant diversity, carbon stocks and environmental factors along a successional gradient in a subalpine coniferous forest in Southwest China. For Ecol Manag. 2011;262(3):361–9.View ArticleGoogle Scholar
- Mathew MM, Majule AE, Sinclair F, Marchant R. Relationships between on-farm tree stocks and soil organic carbon along an altitudinal gradient, Mount Kilimanjaro, Tanzania. For Trees Livelihoods. 2016;25(4):255–66.View ArticleGoogle Scholar