Teshome Soromessa

Structure and regeneration status of Komto Afromontane moist forest, East Wollega Zone, west Ethiopia

We conducted a study in Komto Forest in East Wollega Zone, Oromia National Regional State, West Ethiopia for determining vegetation structure and regeneration status in this forest. We systematically sampled 53 quadrats (20 m × 20 m) along line transects radiating from the peak of Komto Mountain in eight directions. Vegetation parameters such as DBH, height, seedling and sapling density of woody species, and location and altitude of each quadrat were recorded. In total, 103 woody plant species of 87 genera and 45 families were identified. Analysis of selected tree species revealed different population structures. Generally, the forest was dominated by small trees and shrubs characteristic of secondary regeneration. Observations on the regeneration of the forest indicated that there are woody species that require urgent conservation measures. Based on the results of this study, we recommend detailed ecological studies of various environmental factors such as soil type and properties, and ethnobotanical studies to explore indigenous knowledge on uses of plants.

Carbon Stock Analysis along Slope and Slope Aspect Gradient in Gedo Forest: Implications for Climate Change Mitigation

Tropical forests have the largest potential to mitigate climate change amongst the world’s forests through conservation of existing carbon pools and expansion of carbon sinks . Ethiopia is one of tropical country which has significant forest resource but the studies on carbon stock variation along environmental variables have not been well studied. This study was done with the aim of assessing carbon stock amount variation along slope and slope aspect gradient in Gedo forest. Data was collected from 10 m × 20 m plot along transect in systematically stratified forest part. The largest total mean carbon stock (570.67 ± 40 ton ha-1) was found in lower slope class and the lowest total mean carbon stock (421.2 ± 56.2 ton ha-1) was found in higher slope class. The deadwood biomass was only found in lower slope class. The highest mean total carbon stock was calculated in east slope aspect (778.13 ± 75.93 ton ha-1) and the lowest mean total carbon stock was calculated in south west slope aspect (358.58 ± 73.45 ton ha-1). Slope has significant effect on leaf litter biomass carbon. Slope aspect has significant effect on aboveground biomass and below ground biomass carbon, soil organic carbon and total carbon density. Based on overall result it is concluded carbon stock in a forest ecosystem is determined by slope aspect and slope gradient.

Allometric equations for aboveground biomass estimation of Olea europaea L. subsp. cuspidata in Mana Angetu Forest

ABSTRACT Introduction: African wild olive, Olea europaea L. subsp. cuspidata (Wall. ex G. Don) Cif., L ‘Olivicoltore is widely distributed in dry forest and forest margins, often with Juniperus procera, in east Africa and Ethiopia. It reaches southern Africa, also India and China, ranging from tall trees to stunted shrubs. Does best in good forest soil, but hardy and drought resistant once established, even in poor soils. It is used for firewood, charcoal, poles, posts, timber (furniture, carving, floors, and paneling), medicine (stem, bark, and leaves), bee forage, milk flavoring (smoking wood), toothbrushes (twigs), and walking sticks. Although the species has many economic and ecological functions, its environmental uses like carbon storage and climate change mitigation are less assessed. Therefore, the objective of the study was to develop species-specific allometric equations for O. europaea L. subsp. cuspidata using semi-destructive method and evaluate allometric models for estimating the aboveground biomass (AGB). Results and Discussions: After all the necessary biomass calculations were done, seven AGB equations were developed. These regression equations relate AGB with diameter at breast height (DBH), height (H), and density (ρ) individually and in combination. Out of seven, four allometric equations were chosen based on goodness-of-fit statistics and three were rejected. The selected models were tested for accuracy based on observed data. The best models selected have higher R2-adj and lower residual standard error and Akaike information criterion than rejected equations. The relations for all selected models are significant (p < 0.000), which showed strong correlation of AGB with selected dendrometric variables. Accordingly, the AGB was strongly correlated with DBH and was not significantly correlated with wood density and height individually in O. europaea L. subsp. cuspidata allometric equation development. In combination, AGB was strongly correlated with DBH and height; DBH and wood density; and the combination of DBH, height, and wood density. Species-specific equations are used for better carbon assessment than general equations.

Land suitability assessment for major crops by using GIS-based multi-criteria approach in Andit Tid watershed, Ethiopia

Abstract Land evaluation is a foundation for sustainable land resource planning and management. In Ethiopia, national economic development is highly dependent on agriculture. And, the productivity of the land is low as a result of land degradation due to mismanagement of the land and intensive cultivation; this situation is worse in Ethiopian Highlands like Andit Tid watershed. Therefore, matching crop requirement with resource available through land suitability analysis has become an urgent need to sustain the productivity of agricultural land in the study area. This study aimed to address land suitability analysis by using geographical information system-based multi-criteria approach in Andit Tid watershed. The analysis of land suitability for major crops (wheat and barley) revealed that, though, there are slight variation in suitable classes for each crop, most part of the watershed was moderately suitable for both crops with 266.55 ha (77.42%) and only very small part of the land 2.43 ha (0.51%) was highly suitable for both crops. On the other hand, 9.3 ha (2%) and 3.6 ha (0.77%) of the land was marginally suitable and not suitable for both wheat and barley crops, respectively. The main limiting factors for land suitability were soil depth, texture, temperature, slope and erosion hazard. The spatial distribution showed that most of the cultivation currently practised in marginally suitable land in the lower part of the watershed. Most of the land parcel being used against its suitability potential in study area. Thus, land-use pattern needs to be modified based on its suitability potential.

Carbon stock of Banja forest in Banja district, Amhara region, Ethiopia: An implication for climate change mitigation

ABSTRACT This study estimates the carbon stock of Banja Forest which is natural and dry Afromontane forest type in Banja District, northwest of Ethiopia. A systematic sampling method was used to identify each sampling point through the Global Positioning System. A total of 63 plots measuring 20 × 20 m were employed to collect tree species and soil data. Losses on ignition and the Walkley–Black method were used to estimate biomass and soil carbon stock, respectively. The carbon stock of trees was estimated using an allometric equation. The results revealed that the total carbon stock of the forest was 639.87 t/ha whereas trees store 406.47 t/ha, litter, herbs, and grasses (LHGs) 2.58 t/ha and soil 230.82 t/ha (up to 30 cm depth). The carbon pools’ carbon stock variation with altitude and slope gradients were not significant (p > 0.05) which was similar to other previous studies. The Banja Forest is a reservoir of high carbon and thus acts as a great sink of the atmospheric carbon. It can be concluded that the Forest plays a role in climate change mitigation. Hence, it should be integrated with reduced emission from deforestation and degradation (REDD+) and the clean development mechanism (CDM) of the Kyoto Protocol to catch monetary benefits.

Carbon Stock Analysis along Forest Disturbance Gradient in Gedo Forest:Implications of Managing Forest for Climate Change Mitigation

Forests are known to play an important role in regulating the global climate. Ethiopia has a substantial forest resource; however, these forests are facing a rapid rate of deforestation and degradation. This in turn adversely affects forest carbon stock under studied in Ethiopia. This study explores the variation of carbon stock due to a forest disturbance gradient in Gedo forest. Data were collected from 200 m2 plot along transect in a systematically stratified forest part. Spatial distribution of the carbon stock varied within forest disturbance gradient. More aboveground biomass (356.11 ± 37.83 ton/ha), belowground biomass (71.22 ± 7.56 ton/ha) and total carbon (615.16 ± 47.58 ton/ha) were found in the least disturbed stand and the lower total carbon (410.32 ± 52.22 ton/ha) was found in the highly disturbed stand. Dead wood biomass carbon pool was found in least and semi-disturbed stand. Forest disturbance had a significant effect on aboveground biomass, belowground biomass carbon, total carbon density and dead wood biomass carbon. Forest disturbance had an inverse moderate significant correlation with the first three pools and an inverse weak correlation with the later pool. Carbon sequestration in a forest ecosystem was determined by level of human-induced disturbances.

Detection of Olea europaea subsp. cuspidata and Juniperus procera in the dry Afromontane forest of northern Ethiopia using subpixel analysis of Landsat imagery

Abstract. Comprehensive and less costly forest inventory approaches are required to monitor the spatiotemporal dynamics of key species in forest ecosystems. Subpixel analysis using the earth resources data analysis system imagine subpixel classification procedure was tested to extract Olea europaea subsp. cuspidata and Juniperus procera canopies from Landsat 7 enhanced thematic mapper plus imagery. Control points with various canopy area fractions of the target species were collected to develop signatures for each of the species. With these signatures, the imagine subpixel classification procedure was run for each species independently. The subpixel process enabled the detection of O. europaea subsp. cuspidata and J. procera trees in pure and mixed pixels. Total of 100 pixels each were field verified for both species. An overall accuracy of 85% was achieved for O. europaea subsp. cuspidata and 89% for J. procera. A high overall accuracy level of detecting species at a natural forest was achieved, which encourages using the algorithm for future species monitoring activities. We recommend that the algorithm has to be validated in similar environment to enrich the knowledge on its capability to ensure its wider usage.