Dry Afromontane Forest Research Articles

Aboveground biomass estimation and mapping using Sentinel-2 data in a dry afromontane forest

ABSTRACT Forest biomass estimates are required for many applications, including accounting for the role of forests in the global carbon cycle, supporting sustainable forest management and making informed decisions. For all these applications and others, accurate and reliable forest biomass estimates are required. This study evaluated the potential of Sentinel-2 data for predicting and mapping aboveground biomass (AGB) of a dry Afromontane Forest in Tigray, Northern Ethiopia. Multiple linear regression was employed to model the relationship between AGB and Sentinel-2-derived spectral variables. The evaluation criteria for best-fit model selection were based on the coefficient of determination (R2), root mean square error (RMSE, %), and bias (Bias, %). All the spectral variables evaluated here were significantly correlated with AGB (p < 0.01). The model that includes a fraction of photosynthetically active radiation (FAPAR), leaf area index (LAI), Band 2 and Band 3 as predictor variables provided the best predictive performance for AGB in the study area (R 2 = 0.38, RMSE = 13.62 Mg ha−1 and Bias = -3.10 Mg ha−1). The predicted AGB of the study area ranges from 0.1 to 141.8 Mg ha−1, with a mean value of 12.4 Mg ha−1. The results from this study suggested that Sentinel-2 data can be potentially applied for estimating and mapping AGB in dry Afromontane forests.

Revealing suitable habitats for Juniperus procera and Olea europaea tree species in the remnant dry Afromontane forests of Ethiopia: Insights from ensemble species distribution modeling approach.

Human activities and climate change pose a significant threat to the dry Afromontane forests in Ethiopia, which are essential for millions of people both economically and ecologically. In Ethiopia, trees are planted elsewhere even if they are not likely to be well suited to the area. This study aims to identify the suitable habitat for the most exploited Juniperus procera (J. procera) and Olea europaea (O. europaea) tree species in northern Ethiopia. As inputs, least correlated temperature, moisture, soil, and topographic variables were selected through a stepwise procedure. The study evaluated five individual and ensemble models using the area under the curve (AUC) and true skill statistic (TSS) values. The ensemble model outperformed with mean AUC of 0.95 and TSS of 0.78 for J. procera, while securing the second position for O. europaea with an AUC of 0.88 and TSS of 0.71. Climatic factors emerged as the most influential, followed by soil and topography. Suitable areas for both species were found when Isothermality (Bio3) values range from 52% to 62%, temperature seasonality (Bio4) of 16-29°C. Moreover, well drained soils with soil texture not heavier than sandy clay, and soil organic carbon ranging from 5 to 42 g kg-1 were found suitable. The optimal suitable altitude for J. procera and O. europaea was determined to be 2200-2600 and 2100-2500 m.a.s.l., respectively. The suitable areas for J. procera and O. europaea were estimated to be 3130 and 3946 km2, respectively. Furthermore, potential plantation areas were identified beyond Desa'a and Hugumbirda Grat-Kahsu protected forests, covering 2721 km2 (86.9%) for J. procera and 3576 km2 (90.6%) for O. europaea. These findings hold significance for the conservation and sustainable management of these valuable tree species in northern Ethiopia. We recommend implementing a similar approach for other locally restricted dry Afromontane tree species with wider potential distribution.

Exploring the role of canopy cover and environmental factors in shaping carbon storage in Desa’a forest, Ethiopia

BackgroundDry Afromontane forests play a vital role in mitigating climate change by sequestering and storing carbon, as well as reducing greenhouse gas emissions. Despite previous research highlighting the importance of carbon stocks in these ecosystems, the influence of canopy cover and environmental factors on carbon storage in dry Afromontane forests has been barely assessed. This study addresses this knowledge gap by investigating the effects of environmental factors and vegetation cover on carbon stocks in Desa’a forest, a unique and threatened Afromontane dry forest ecosystem in northern Ethiopia. Data on woody vegetation, dead litter, grass biomass, and soil samples were collected from 57 plots. A one-way analysis of variance (ANOVA) was performed at a 95% confidence level (α = 0.05) to examine the influence of canopy cover and environmental factors on the carbon stocks of various pools.ResultsAmong the 35 woody species identified, Juniperus procera was the most dominant, while Carissa edulis Vahl and Eucalyptus globulus were the least dominant. The average total carbon stock was 92.89 Mg ha−1, with contributions from aboveground carbon, below-ground carbon, litter carbon, grass carbon, and soil organic carbon. Among the carbon pools, soil organic carbon had the highest carbon stock, accounting for 76.8% of the total, followed by above-ground biomass carbon at 17.7%. Significant variations in carbon stocks were found across altitude class and canopy level but not slope and aspect factors.ConclusionsIn summary, altitude and canopy level were found to significantly influence carbon stocks in Desa’a forest, providing valuable insights for conservation and climate change mitigation efforts in dry Afromontane forests. Forest intervention planning and management strategies should consider the influence of different environmental variables and tree canopy levels.

Composition and Structural Diversity of Woody Species in the Wof Ayzurish Forests, the Dry Afromontane Forest of the Northern EthiopiaI

Dry Afromontane Forest (DAF) is the largest Afromontane section and plays a fundamental role in preservation of species biodiversity. Despite its biodiversity, DAF is the most altered and threatened in the Ethiopian ecosystem. With the exception of a few isolated pockets left in some sacred places and protected areas of the country, most of forests are inaccessible. The scenario is not different for the present study forest. Therefore, the objective of the present study is to investigate woody species diversity, structure and regeneration status of Wof Ayzurish Forest, which is a dry Afromonatane in North Shewa of Ethiopia. A systematic method was employed whereby 67 quadrats set in 8 parallel lines transecting at 300-meter intervals and quadrats at 150-m distance. All trees and shrubs with diameters of breast height > 2.5 cm and height > 2 m were measured. The results revealed that Wof Ayzurish Forest harbors 76 species of woody plants that belong to 68 genera and 47 families, with Asteraceae, Fabaceae, and Solanaceae displaying the highest diversity. Shrubs had the highest composition than trees. The most abundant plants were Dodonaea viscosa subsp. angustifolia, Carissa spinarum, Juniperus procera, Olinia rochetiana and Olea europaea subsp. cuspidata. Dodonaea viscosa subsp. angustifolia was the most prominent plant, occurring in 98.5 % of all sample plots. The DBH and height classification pattern exhibited that the forest had a classic inverted J-shape, dominated by smaller trees and shrubs, indicating a secondary stage of regeneration. Total basal area (BA) for trees and shrubs DBH > 2.5 cm was 18.03 m2 ha−1. Remarkably, five species accounted for 57.45 % of the basal area, indicating that higher numbers of individuals concentrated in lower DBH classes. By using R software, agglomerative hierarchical cluster analysis and Canonical Correspondence Analysis (CCA) has done to identify plant community types and examine the relationship between plant community types and environmental variables, respectively. Three significantly different (p < 0.05) plant community types were identified. The CCA results showed that species diversity and community composition among community types were significantly influenced by altitude and human disturbance such as expansion of agriculture, cuttings, and grazing. Therefore, it is recommended that community-based methods and awareness creation should be devised in order to implement sustainable forest conservation.

Mixed-Effects Height Prediction Model for Juniperus procera Trees from a Dry Afromontane Forest in Ethiopia

Tree height is a crucial variable in forestry science. In the current study, an accurate height prediction model for Juniperus procera Hochst. ex Endl. trees were developed, using a nonlinear mixed-effects modeling approach on 1215 observations from 101 randomly established plots in the Chilimo Dry Afromontane Forest in Ethiopia. After comparing 14 nonlinear models, the most appropriate base model was selected and expanded as a mixed-effects model, using the sample plot as a grouping factor, and adding stand-level variables to increase the model’s prediction ability. Using a completely independent dataset of observations, the best sampling alternative for calibration was determined using goodness-of-fit criteria. Our findings revealed that the Michaelis–Menten model outperformed the other models, while the expansion to the mixed-effects model significantly improved the height prediction. On the other hand, incorporating the quadratic mean diameter and the stem density slightly improved the model’s prediction ability. The fixed-effects of the selected model can also be used to predict the mean height of Juniperus procera trees as a marginal solution. The calibration response revealed that a systematic selection of the three largest-diameter trees at the plot level is the most effective for random effect estimation across new plots or stands.

Population and conservation status of the endangered Dracaena ombet tree in dry Afromontane forests

Dracaena ombet, a flagship tree species in arid ecosystems, holds a significant ecological, economic, and socio-cultural value. However, its persistence is currently under threat from both anthropogenic and natural factors. Consequently, the species has been listed as an endangered tree species on the IUCN Red List, requiring urgent conservation actions for its continued existence. To develop effective conservation actions, it is necessary to have information on the population dynamics of the species. A study was conducted in the lowland and midland agroecological zones (sites) within the Desa'a dry Afromontane forest, northern Ethiopia to analyze the population status of D. ombet and identify its site-specific threats. At each site, abundance, health status, diameter, height and threats of the species were collected using 60 sample plots (20 m × 20 m) distributed over six transects (500 m × 20 m) spaced one km apart. The study showed that the D. ombet population was characterized by low abundance and unstable structure. It was further characterized by a substantial number of unhealthy damaged and dead trees. The low abundance of the species with unstable age structure in the dry Afromontane forests can be attributed to various factors such as stem cutting and debarking, leaf defoliation, overgrazing, soil erosion, and competition from expansive shrubs. Alternative livelihood options for the local inhabitants should be introduced to minimize the overexploitation of D. ombet for subsistence use in the dry Afromontane forests. The impacts of overgrazing and soil erosion on D. ombet and its Desa'a habitats should also be addressed through the introduction of community-based exclosures and in-situ soil and water conservation practices, respectively.

Ecological determinants in plant community structure across dry afromontane forest patches of Northwestern Ethiopia

Ethiopia is a mountainous country with great geographic diversity. The diversified topographic features in Ethiopia made the country have a rich biodiversity forest cover in tropical Africa. This made Ethiopia have the largest floral diversity in tropical Africa. This floral diversity is rich in endemic elements. About 6,027 vascular plant species (including subspecies) with about 10.7% endemism have been documented. Plant community types are primarily influenced by topographic factors, as well as disturbance and environmental factors. The objective of this study is to demonstrate that 1: The forest patches in the study area exhibit distinct plant community types. 2: The composition and structure of these plant communities are influenced by various environmental variables. To achieve this, a total of 76 plots were used to collect vegetation and environmental data. The collected data were then analyzed using the R software, employing agglomerative hierarchical cluster analysis and redundancy analysis (RDA) to identify plant communities and assess the relationship between these communities and environmental variables.R software was used to identify plant communities and analyze the relationship between plant community types and environmental variables using agglomerative hierarchical cluster analysis and redundancy analysis (RDA). Four plant community types were identified. The RDA results highlighted the significant impact (p < 0.005) of altitude, aspect, slope, grazing, and human interference on species distribution and the formation of plant communities. The RDA results highlighted the significant impact (p < 0.005) of altitude, aspect, slope, grazing, and human interference on species distribution and the formation of plant communities.The findings indicate that the variation in plant communities is closely associated with topographic factors such as altitude, slope, aspect, as well as disturbance factors like grazing, and human interference, with altitude being the most influential factor. Based on these findings, it is recommended that conservation plans take into consideration the effects of grazing and human interference in order to address the challenges faced in conserving forest patches in the future.Additionally, further research efforts should focus on mitigating disturbance factors and understanding the environmental variables that affect forest patches to enhance their conservation.

Vegetation density and altitude determine the supply of dry Afromontane forest ecosystem services: Evidence from Ethiopia

Mapping forest ecosystem services (ES) and identifying both natural and anthropogenic factors influencing their supply and distribution is a key step for sustainable and climate-smart forest management planning. This is particularly important for dry and mountain forests which are among the most threatened and neglected ecosystems globally. These forests are facing increasing demands for different land uses and ES with rising conflicts with each other.This study identifies, quantifies, and maps the spatial distribution of one supporting, three regulating, and four provisioning forest ES. Furthermore, a set of potential natural and anthropogenic factors influencing ES distribution in Desa’a forest, a dry Afromontane Forest in Tigray, Ethiopia, was assessed. The supply of some of the assessed ES depended on vegetation density, while the supply of others depended on woody species diversity, which resulted in a clustering of ES in two different geographical areas. Both natural and anthropogenic factors were important for explaining variations in the spatial distribution of ES, of which altitude and vegetation density were the most influential factors.Our findings can contribute to the development of sustainable forest management strategies for dry and mountain forests by providing knowledge on the spatial supply of ES. The ES maps can be used as a basis for developing dedicated zoning plans which could improve forest management.

Remote sensing reveals how armed conflict regressed woody vegetation cover and ecosystem restoration efforts in Tigray (Ethiopia)

In recent years, armed conflicts are globally on the rise, causing drastic human and environmental harm. The Tigray war in Ethiopia is one of the recent violent conflicts that has abruptly reversed decades of ecosystem restoration efforts. This paper analyzes changes in woody vegetation cover during the period of armed conflict (2020–2022) using remote sensing techniques, supplemented by field testimony and secondary data. Extent of woody vegetation cover was analyzed using Normalized Difference Vegetation Index (NDVI) thresholding method from Sentinel 2 images in Google Earth Engine, and scale of de-electrification was qualitatively analyzed from Black Marble HD nighttime lights dataset, acquired from NASA's Black Marble team. The magnitude, direction as well as the mechanisms of change in woody vegetation cover varied across the region and over time. Tigray's woody vegetation cover fluctuated within 20% of the landmass. Mainly scattered to mountainous areas, the dry Afromontane forest cover declined from about 17% in 2020 to 15% in 2021, and 12% in 2022. About 17% of the overall decline was observed between 500 m and 2000 m elevation, where there is higher anthropogenic pressure. Land restoration practices meant to avert land degradation and desertification were interrupted and the area turned warfare ground. In many areas, forests were burned, the trees cut and the area became barren. The suspension of public services such as electricity for household or industrial use created heavy reliance on firewood and charcoal, further threatening to compound weather and climate. The magnitude of disturbance in a region that is already at a very high risk of desertification requires urgent national and international attention. Continued ecosystem disturbance could eventually make the domain part of a wider desert connecting the Sahel to the Afar Triangle, a scenario which may render the area uninhabitable.

Impact of land-use and climate change on the population structure and distribution range of the rare and endangered Dracaena ombet and Dobera glabra in northern Ethiopia

Dracaena ombet and Dobera glabra are some of the most important rare and endangered tree species in dryland areas. Unfortunately, their sustainability is being compromised by different anthropogenic and natural factors. However, impacts of the on-going land-use and climate change on the population structure and distribution of the species are less explored. This study was carried out in the grazing lands and hillside areas of the Desa'a dry Afromontane-forest, northern Ethiopia, to characterize the population structure of the species and predict the impact of climate change on their potential distributions. In each land-use type, abundance, diameter and height of the trees were collected using 70 sampling plots distributed over seven transects spaced one km apart. The geographic coordinates of each individual tree were also recorded. The results showed that the species populations were characterized by low abundance and unstable population structure. The latter was evinced by a lack of seedlings and mature trees. The study also revealed that the total abundance and dendrometric traits of the trees were significantly different between the two land-uses. The hillside areas had denser abundance with bigger and taller trees than the grazing lands. Climate change predictions using the MaxEnt model highlighted that future temperature increases coupled with reduced precipitation would lead to significant reductions in the suitable habitats of the species in northern Ethiopia. The species suitable habitats were predicted to decline by 48–83% for D. ombet and 35–87% for D. glabra. Hence, to sustain the species populations, different strategies should be adopted, namely the introduction of alternative livelihoods (e.g., gathering NTFP) to reduce the overexploitation of the species for subsistence livelihood, and the protection of the current habitats of the species that will remain suitable in the future using community-based exclosures. Additionally, the preservation of the species' seeds in gene banks is crucial to ensure their long-term conservation.

Species-Specific Allometric Equations, Biomass Expansion Factor, and Wood Density of Native Tree Species in the Dry Afromontane Forest of Ethiopia

A forest is a storehouse of carbon released from different sources when the activities of sustainable forest management, planting, and rehabilitation exist. However, few allometric equations are present to determine its contribution to carbon reduction. The target of the study was to develop species-specific allometric equations and establish a database for biomass expansion factor and wood density for five tree species grown in the dry Afromontane forest of Ethiopia. A direct or destructive sampling method was used on 62 trees from different diameter classes. The diameter at breast height and the total height of selected trees ranged from 7 to 48 cm and 6.7 to 23.4 m, respectively. Trees were felled and divided into various biomass sections. Stem and big branch discs were sampled to determine the wood density and volume of the trees. Sample wood and foliage were oven-dried for three days and two days at 105°C and 70°C, respectively, to get their dry weight. Total above-ground biomass was regressed using diameter at breast height, total height, wood density, and average crown diameter as independent variables. R software version 4.0.1 was used to fit the biomass equations. The best biomass models were determined to have lower AIC and RSE and highest adj. R2. The biomass expansion factor and wood density of five tree species ranged from 1.19 to 1.40 and 0.53 to 0.74 g/cm−3, respectively. Species-specific allometric equations were better than both mixed species and pan tropical models for the assessment of above-ground biomass in the Chilimo dry Afromontane forest of Ethiopia.

Environment differentially affects the functional and phylogenetic structures of plant communities in a dry evergreen Afromontane tropical forest

AbstractTesting how local environmental conditions influence plant community assembly is important to understand the underlying mechanisms that promote and/or maintain biodiversity. Functional traits are used to find the broad spectrum of resource use strategies that plants use to respond to environmental variation. The patterns and drivers of plant community assembly through the lens of traits and phylogeny; however, remain to be studied in a uniquely biodiversity rich but poorly known fragmented dry Afromontane forest of Ethiopia. Here, we combined trait and community phylogenetic data from thirty sampling plots of 20 × 20 m size to determine the functional and phylogenetic structures and their drivers in a fragmented, human‐dominated dry evergreen Afromontane forest. We found phylogenetic and functional clustering of plants in which the effect of environment was found to be trait specific. A weak phylogenetic signal for traits was detected suggesting that species resource use strategies may not be inferred using species phylogenetic distance. Additionally, we found functional traits to be weak in predicting species abundance distribution. Overall, while this study shows a non‐random community assembly pattern, it also highlights the importance of deterministic processes being trait specific.Abstract in Amharic is available with online material.

Floristic composition and plant community distribution along environmental gradients in Guard dry Afromontane forest of Northwestern Ethiopia

BackgroundDry evergreen montane forests of Ethiopia provide economic and ecological services for the community but it is under several threats of natural and anthropogenic disturbances. The study aimed to investigate the floristic composition, species diversity, and plant community distribution of Guard forest along environmental gradients.MethodsA systematic sampling technique was used to collect vegetation and environmental data. Fifty eight plots each with 400 m2 (20 m X 20 m) were established for trees and shrubs and 2 m x2m (4 m2) for herbs along eleven transect lines. Shannon Weiner diversity index and evenness were used to assess the species diversity and richness. The similarities among plant communities were computed using Sorenson’s similarity index. The plant community types and vegetation-environment relationships were analyzed using hierarchical cluster analysis and Canonical correspondence analysis (CCA) in R software, respectively.ResultsA total of 137 plant species belonging to 111 genera and 55 families were identified. The most dominant families in the study area were Fabaceae and Asteraceae. Among the total plant species documented in the forest, 42(30.65%) were trees, 36 (26.28%) were shrubs, 48(35.04%) were herbs, and 11 (8.03%) were climbers. Of the total species, 14(10.22%) species are endemic to Ethiopia and Eritrea. Three plant community types were identified by cluster analysis. The Shannon-Weiner Diversity Index was 3.39 and evenness was 0.87 for the forest. The pattern of plant species distribution was significantly influenced by altitude, pH, BD, slope, and charcoal (P < 0.05).ConclusionGuard forest has good species diversity and richness, and supports different endemic plant species that show the potential of the area to support useful but some of the characteristics species are not found in the forest and others are rare in their existence due to the presence of disturbances and need immediate conservation to ensure sustainable use and management of the forest.

Distribution of expansive shrubs under climate change scenarios and their socio-economic impacts in a dry Afromontane Forest

Native plants that expanded into new geographical areas after human-induced disturbances and climate change are referred to as expansive species. This study aimed to model the current and future distribution of Cadia purpurea and Tarchonanthus camphoratus, two expansive shrubs in the Desa'a dry Afromontane Forest in northern Ethiopia, and analyze their socio-economic impacts. Using ArcGIS and MaxEnt, the distributions were modeled under two shared socio-economic pathways (SSP2.6 and SSP8.5) of climate change scenarios for three time periods: 1970–2000 (current), 2050s, and 2070s (future). About 124 records of species occurrence, elevation, aspect, slope, and 19 bioclimatic variables were used to determine the current and future distribution. The socio-economic impacts of the two expansive shrubs were assessed through household surveys, focus group discussions, and interviews with key informants. We used a t-test for continuous variables and a chi-square for categorical variables to test the significance of differences in means between invaded and uninvaded areas by the expansive shrubs using R software. The result showed that the mean area under the curves (AUC) for the replicate runs were 0.901 and 0.903 for Cadia purpurea and Tarchonanthus camphoratus, respectively, indicating that the model's predicted result was very accurate and reliable. Precipitation was determined to be the most significant bioclimatic variable, accounting for 82.6% and 79.5% of the variability in the distribution of Tarchonanthus camphoratus and Cadia purpurea, respectively, in the study area. The socio-economic result indicated that human activities such as illegal cutting, settlement expansion, road construction, agricultural expansion, and free grazing were found to facilitate the spread of these species. The expansive species provide a number of services, such as firewood, charcoal production, construction material, shading, erosion control, bee forage, medicine, and fencing. However, they also have adverse impacts, such as biodiversity loss, reduced crop yields, reduced water sources, suppressed grass growth, and reduced tourism income. Local communities recommended physical, chemical, and biological mechanisms to manage and control the expansion of these species in the Desa'a forest, as their negative impacts outweigh their positive impacts.

Population Structure and Regeneration Status of Woody Plant Species in Tulu Korma Dry Afromontane Forest, West Shewa Zone, Oromia, Ethiopia.

A study was conducted on Tulu Korma afromontane forest to assess woody plant species' population structure and natural regeneration status. Data were collected from 52 main quadrats of 400 m2 for mature woody species and 260 subplots of 25 m2 for seedlings and saplings. All live woody plant species were recorded with their densities, heights, and DBH. Frequency, basal area, importance value, and Shannon-Wiener diversity indices were computed. A total of 101 species that belonged to 45 families were documented. Diversity and evenness indices were 3.44 and 0.7, respectively. Combined density of woody species of all developmental stages was 4971 stems ha-1 of which 39, 32, and 28% were with DBH < 3.5 cm (seedlings), between 2 and 10 cm (saplings), and >10 cm (mature wordy species), respectively. The total basal area of individuals with DBH ≥ 3.5 cm was 116.18 m2 ha-1. Olea europaea and Podocarpus falcatus were the most dominant species. About 41.58% of the species had IVI < 1. Population structure based on combined densities revealed that density of seedling > sapling > mature individuals, suggesting healthy population structure and good regeneration. On individual basis, however, species showed different patterns of population structure of which 12, 51, and 37% species showed good, fair, and poor regenerations, respectively. Species with least IVI and poor regeneration should be given conservation priority.

Prioritizing forest conservation strategies using a multi-attribute decision model to address concerns with the survival of the endangered dragon tree (Dracaena ombet Kotschy and Peyr.)

The globally endangered Dracaena ombet is one of the ten dragon multipurpose tree species in arid ecosystems. Anthropogenic and natural factors are now impacting the sustainability of the species. This study was conducted to prioritize criteria and alternative strategies for conservation of the species using the Analytical Hierarchy Process (AHP) model by involving all relevant stakeholders in the Desa'a dry Afromontane forest, northern Ethiopia. Information about the potential alternative strategies and the criteria for their evaluation were first collected from experts, personal experiences and literature reviews. Afterwards, they were validated using stakeholders' focus group discussions. Five candidate strategies with three evaluation criteria were considered for prioritization using the AHP techniques. The overall priority ranking value of the stakeholders showed that the ecological criterion was deemed as the most essential factor for the choice of the alternative strategies, followed by the economic and social criteria. The minimum cut-off strategy, combining exclosures with collection of only 5% of plant parts from the species, soil and water conservation and habitat protection management options, was selected as the best alternative strategy for sustainable D. ombet conservation. The livelihood losses due to the selected strategy should be compensated by the collection of non-timber forest products, poultry farming, home gardens, rearing small ruminants, beekeeping and agroforestry. This approach may be extended to study other dragon tree species and explore strategies for the conservation of other arid ecosystems.

Linking process to pattern in community assembly in dry evergreen Afromontane forest of Hararghe highland, Southeast Ethiopia

Abstract&#x0D; &#x0D; Many scholars have attempted to identify the role of deterministic and stochastic processes in community assembly, but there is no consensus on which processes dominate and at what spatial scales they occur. To shed light on this issue, we tested two non-exclusive processes, scale-dependent hypotheses: (i) that limiting similarity dominates on small spatial scales; and (ii) that environmental filtering does so on a large scale. To achieve this, we studied the functional patterns of dry evergreen Afromontane forest communities along elevation gradients in southeastern Ethiopia using floristic and functional trait data from fifty-four 0.04 ha plots. We found evidence of functional overdispersion on small spatial scales, and functional clustering on large spatial scales. The observed clustering pattern, consistent with an environmental filtering process, was most evident when environmental differences between a pair of plots were maximized. To strengthen the link between the observed community functioning pattern and the underlying process of environmental filtering, we demonstrated differences in the topographical factors of the most abundant species found at lower and higher elevations and examined whether their abundance varied over time or changed with time along the elevation. We found (i) that the largest functional differences in the community (observed between lower and upper dry evergreen Afromontane forest assemblages) were primarily the result of strong topographical influence; and (ii) that the abundance of such species varied along the elevation gradient. Variation in stand structure and tree species diversity within the DAF plots shows that topography is among the important drivers of local species distribution and hence the maintenance of tree diversity in dry Afromontane forest.&#x0D; Our results support the conclusion that environmental filtering at large spatial scales is the primary mechanism for community merging, since functional grouping pattern was associated with species similarities in topographic variation, ultimately leading to changes in species abundances along the gradient. There was also evidence of competitive exclusion at more homogeneous and smaller spatial scales, where plant species compete effectively for resources.

Carbon stock of Agoro Agu Central Forest reserve, in Lamwo district, Northern Uganda

Terrestrial ecosystems such as forest landscapes provide critical ecosystem services such as carbon sequestration, fundamental to people, society and the global climate change discourse. Just like moist forest, dry Afromontane forests too present a high carbon sequestration potential. However, Uganda has since not undertaken carbon stock inventories for these conservation areas, especially with dry Afromontane forests like Agoro-agu central forest reserve (CFR). So, their potential to capture and store carbon is yet to be understood in Uganda. This study was carried out to estimate carbon stock of Agoro-agu CFR, for its potential in climate change mitigation. A stratified sampling design was used, where 65 sample plots were established. Nested, fixed area circular sample plots with sub-plots of varying radii for tree height, diameter measurements and soil sampling, were used. The mean total carbon stock of Agoro-agu CFR was estimated at 606.7 Mg C ha−1, for which 409, 72, 124 and 0.24 Mg C ha−1 was stored as above ground carbon, below ground carbon, soil organic carbon and carbon in litter herbs and grass respectively. The study illustrates the carbon sequestration potential of the forest reserve for any results-based payment projects for climate change mitigation. This is mainly due to the interventions through collaborative forest management arrangements and the pro-poor reducing emissions from Deforestation and forest Degradation (REDD+) pilot project in the landscape. This however, calls for more multi-stakeholders’ collaboration from direct resource users to national level to enhance forest conservation and reduce forest degradation for sustainable resource benefits and other ecosystem services.

Analysis of Charcoal Producers Perceptions of Its Production, Forest Degradation, and Governance in Wolaita, Southern Ethiopia’s Dry Afromontane Forests

The purpose of this study was to assess charcoal producers’ perceptions of forest degradation and investigate governance in the dry Afromontane forests of Wolaita Zone, Ethiopia. It also examines the socioeconomic contribution of charcoal production to livelihood improvement and the effect of charcoal production on forest degradation and biodiversity loss. Three Kebeles (smallest administrative subunits): Galda, Sere Esho, and Mancha Gugara were purposely selected based on their potential for charcoal production. Semistructured questionnaires were used for household surveys, while checklists were provided for the key informants and focus group discussions. From the total 4,739 charcoal producer households in the selected Kebeles, 98 households were randomly selected and interviewed considering time and budget limitations. Besides, 6 key informant interviews with elders, forestry experts, and farmers and 3 focus group discussions were conducted. A simple descriptive statistical tool was used to analyze descriptive statistical data and chi-square at P &lt; 0.05 was used to describe the association of forest degradation with socioeconomic characteristics. The findings reveal that charcoal production is dominated by males (68.4%) compared to females, who were within the age range of 20‒43 years. About 59.18% did not attend any formal education and 18.37% attended elementary education. Charcoal production (32.7%) is second, following agricultural expansion (39.8%) in its negative contribution to forest degradation. The majority (76%) of charcoal producers participated in charcoal production at all times throughout the year. The chi-square result shows a significant relationship between monthly incomes, educational status, family size, and gender with charcoal production and forest degradation at ( P &lt; 0.05 ). The indigenous trees, Acacia tortilis (34%), Combretum mole (22%), and Terminalia schimperiana (16%), were the most preferred tree species used for charcoal production. Overall, charcoal production has resulted in forest degradation. Charcoal producers have used traditional earth mound kiln technology. Providing alternative energy sources, training, starting rehabilitation programs, and implementing policies and legal frameworks are needed for the sustainable utilization of the resources and to improve the livelihood of the communities.

Aboveground Biomass Models for Indigenous Tree Species in the Dry Afromontane Forest, Central Ethiopia

The application of biomass models for quantifying forests’ above-ground biomass is essential for sustainable forest management. However, lack of knowledge in modelig biomass of individual tree growth hinders the sustainable management of Dry Afromontane forests. In this study, models to estimate above-ground biomass were developed for Rhus ruspolii, Ekebergia capensis, and Nuxia congesta. To develop the models, a total of 45 trees from different diameter classes were selected, felled, and divided into different biomass compartments. For the model’s development, diameter at breast height (DBH), total height (TH), diameter at stump height (DSH), and wood density (WD) were used as independent variables. Models’ performances were evaluated using RSE, adjusted coefficient of determination, and AIC. Also, model validations were done by using rRMSE, mean absolute deviation, bias, and coefficient of variation. Models 5 (Adj-R2 = 0.92), 6 (Adj-R2 = 0.97), and 8 (Adj-R22 = 0.82) were the best fitted models for Nuxia congesta, Ekebergia capensis, and Rhus ruspolii, respectively. The average wood densities of Ekebergia capensis, Nuxia congesta, and Rhus ruspolii were 0.59, 0.50, and 0.69, respectively. The variation between observed biomass and estimated biomass using new models was statistically not significant (p&gt;0.05). Thus, the biomass models developed here can be important tools to accurately estimate above-ground biomass in the Menagesha Suba forest and can be integrated into decision support tools.