Afromontane Forests Of Ethiopia Research Articles

Woody Species Composition, Plant Communities, and Environmental Determinants in Gennemar Dry Afromontane Forest, Southern Ethiopia.

Dry Afromontane forests in Ethiopia are vital for the conservation of plant diversity and climate change mitigation. However, these forest resources are rapidly degrading and shrinking, necessitating empirical scientific investigations to ensure their successful conservation and long-term management. As a result, this study was conducted to evaluate the composition, plant communities, and environmental determinants of woody species in the Gennemar dry Afromontane forest of southern Ethiopia. Environmental variables such as altitude, aspect, and geographical location were recorded from 46 plots of 20 × 20 m for trees and 92 subplots of 10 × 10 m for shrubs were laid along 10 transect lines. Vegetation structure, diversity, vegetation classification, importance value index (IVI) and correlation with environmental parameters were analyzed. A total of 55 woody species belonging to 51 genera and 34 families were identified. Among the species identified, Jasminum stans, Maytenus addat, and Pittosporum abyssinicum were endemic to Ethiopia. Celastraceae (with 659 individuals) was the most dominant family, followed by Cupressaceae (268 individuals) and Myrsinaceae (222 individuals). Four plant communities were identified: Syzygium guineense-Mystroxylon aethiopicum, Maytenus arbutifolia-Podocarpus falcatus, Myrsine africana-Erica arborea, and Juniperus procera-Carissa spinarum. Juniperus procera, Podocarpus falcatus, and Maytenus arbutifolia were species with the highest IVI, while Maesa lanceolata, Rhamnus prinoides, and Gnidia glauca had the lowest. The DBH class distribution shows an inverted J-shaped distribution. As DBH increases, the number of individuals decreases in the higher DBH class. The distribution of plant communities and the composition of the species depend on altitude and topographic aspects. The study found that the dry Afromontane Forest is rich in species and that it should be prioritized for conservation to protect endemic and native species. Decisive elements such as the type of species, altitude, and topographic aspects must be considered for forestry activities.

Mixed-Species Allometric Equations to Quantify Stem Volume and Tree Biomass in Dry Afromontane Forest of Ethiopia

Volume and biomass equations are essential tools to determine forest productivity and enable forest managers to make informed decisions. However, volume and biomass estimation equations are scarce for Afromontane forests in Africa in general and Ethiopia in particular. This limits our knowledge of the standing volume of wood, biomass, and carbon stock of the forests therein. In this study, we developed a new mixed-species volume and biomass equations for Afromontane forests and compared them with generic pantropical and local models. A total of 193 sampled trees from seven dominant tree species were used to develop the equations. Various volume and biomass equations were fitted using robust linear and nonlinear regression. Model comparison indicated that the best model to estimate stem volume was ln(v)=-9.909+ 0.954*ln(d2h), whereas the best model to estimate biomass was ln(b)=-2.983+ 0.949*ln(ρd2h) . These equations explained over 85% of the variations in the stem volume and biomass measurements. The mean density and basal area of trees in the forest with d ≥ 2 cm was 631.5 stems·ha-1 and 24.4 m2·ha-1. Based on the newly developed equations, the forest has on average 303.0 m3·ha-1 standing volume of wood and 283.8 Mg·ha-1 biomass stock. The newly developed allometric equations derived from this study can be used to accurately determine the stem volume, biomass, and carbon storage in the Afromontane forests in Ethiopia and elsewhere with similar stand characteristics and ecological conditions. By contrast, the generic pan-tropical and other local models appear to provide biased estimates and are not suitable for dry Afromontane forests in Ethiopia. The estimated stem biomass and carbon stock in the Chilimo forest are comparable with the estimates from various tropical forests and woodlands elsewhere in Africa, indicating the importance of dry Afromontane forest for climate change mitigation.

Aboveground tree biomass prediction options for the Dry Afromontane forests in south-central Ethiopia

Biomass of trees may be predicted either directly applying allometric models or indirectly from volume and biomass expansion factors (BEFs). For the Dry Afromontane forests, the second largest biomass pool in Ethiopia, such methods are not devised and properly documented. The main objective of this study was to explore different aboveground tree biomass prediction options based on destructively sampled tree biomass data. We explored the direct method by means of 1) new mixed-species general biomass models developed in the present study, and 2) some previously developed models including the pan-tropical models, and the indirect method by means of 3) volume and BEFs. From two sites in south-central Ethiopia, based on information from systematic sample plot inventories, 63 trees from 30 different species that contributed about 87% to the total forest basal area, were destructively sampled. Weighted nonlinear regression was applied to fit new models and their performance was assessed using root mean squared error (RMSE, %), mean prediction error (MPE, %) and pseudo-R2 based on leave-one-out-cross-validation. Previously developed models and the indirect method were also evaluated by means of RMSE and MPE. The new general total biomass models performed well with pseudo-R2 ranging between 0.87 and 0.96 and are presented along with covariance matrices for the parameter estimates enabling error propagation in biomass estimation. Most previously developed models resulted in significant MPEs up to 78%, while the best pan-tropical model performed much better with an MPE of about 7%. The indirect method also showed poor performance with MPEs ranging between 5% and 30%. Generally, the new models are accurate and flexible, thus, preferred over all previously developed models and the indirect method for application. However, their application to Dry Afromontane forests outside the study sites should be made only after thoroughly evaluating growing conditions and species composition. The results are step forward to enhance decisions made towards sustainable forest management including the REDD+ implementation for Dry Afromontane forests in Ethiopia.

The arbuscular mycorrhizal fungi status of selected tree nurseries in the Ethiopian highlands

We investigated the arbuscular mycorrhizal fungi (AMF) status of ten nurseries suitable for restoration of dry evergreen Afromontane forests in Ethiopia. We quantified AMF root colonization (RC) and spore abundance (SA) in seedlings of nine native tree species namely Acacia abyssinica Hochst. ex Benth., Cordia africana Lam., Dovyalis abyssinica (A. Rich.) Warb., Hagenia abyssinica J.F. Gmel., Juniperus procera Hochst. ex Endl., Millettia ferruginea (Hochst.) Baker, Olea europaea L. subsp. cuspidata (Wall. ex G. Don) Cif., Podocarpus falcatus (Thunb.) R. Br. ex Mirb. and Prunus africana (Hook. f.) Kalkman. We used the ink and vinegar method to stain AMF in roots. RC levels ranged from 8.00 to 99.67% and were generally higher than the RC levels reported from other similar nurseries in Ethiopia. SA levels ranged from 1 to 25 spores g−1 and were comparable with some reports from the field in Ethiopia but they were lower than levels reported by another similar study. RC was more affected by host species than nursery location, while the reverse was true for SA. The results also showed that nursery management could improve AMF status among seedlings. When all nursery tree species were considered, RC and SA levels were unrelated. No strong correlation existed between the nursery management variables considered and RC or SA. However, considering C. africana, J. procera and P. falcatus separately, RC-age (rs = 0.829, P = 0.042) correlation for O. europaea and RC-pot diameter (rs = 0.820, P = 0.046), RC-pot volume (rs = 0.928, P = 0.008) and SA-age (rs = 0.943, P = 0.005) correlations for C. africana, were significant, strong and positive. Generally, most of the tree species and particularly, early-mid successional tree species had sufficient AMF inoculum. Hence, only the mid-late successional tree species; J. procera, P. falcatus, and P. africana may require AMF inoculation, preferably, during filed planting. Based on our results, age and pot volume were identified to be important variables potentially affecting RC and SA. To better understand the effects of these and other nursery management variables, additional study is required. We demonstrated for the first time that black Hero ink is suitable for staining root AMF and can be used in future AMF research.

Tree species composition, structure and regeneration status in Munessa natural forest, Southeastern Ethiopia

Munessa forest is one of the undifferentiated afromontane forests in Ethiopia. The forest has threatened by deforestation, free grazing and illegal logging. This study aimed to estimate the structure, composition and diversity of tree species and their regeneration status in Munessa natural forest. Vegetation data were collected from 54 plots of 20 m x 20 m for trees and 162 subplots of 5 m x 5 m for seedlings and saplings that were laid along six parallel transect lines. Vegetation structure, basal area, IVI and species prioritization were analyzed using spreadsheet programs. Correlation coefficients, vegetation classification, frequency, Shannon diversity index and Shannon evenness were analyzed using R software version 3.2.2 for windows 8. A total of 41 tree species belonging to 27 families were recorded. Fabaceae was the most dominant family represented by four species followed by Oleaceae and Rutaceae, each having three species. The hierarchical cluster analysis revealed four community types, of which Syzygium guineense - Croton macrostachyus community type, exhibited the highest species diversity and evenness. The Shannon diversity and evenness index for the entire study area was 2.6 and 0.39 respectively. The correlation between elevation and species richness was negative and insignificant (r = -0.545, p < 0.05). The densities of seedlings, saplings and mature trees were 6,934, 1,686 and 481 individuals ha-1 respectively. This indicated that the regeneration status was significantly lower compared to other similar sites. The total basal area of the forest was 91.75 m2ha-1 and its IVI ranged from 0.62 for Calpurnia aurea to 70.29 for Podocarpus falcatus. The estimated values of population structure and regeneration status of the forest indicated that there was a huge disturbance induced by anthropogenic factor particularly free grazing and tree cutting. Therefore sustainable forest management strategies need to be implemented for sustainable utilization of the forest.

Woody species diversity and coffee production in remnant semi-natural dry Afromontane Forest in Zegie Peninsula, Ethiopia

The forest structure and composition of Afromontane forests in Ethiopia, where Arabica coffee is originated and grown as an understorey shrub, have been deteriorating following intensive and ever-increasing management interventions for coffee production. The study conducted in Zege Peninsula Dry Afromontane forest to (1) examine the impacts of coffee production on vegetation composition and forest productivity, (2) document farmers’ forest management practices and tree species preference, and (3) understand the challenges in conserving Zege Peninsula forests. Vegetation data were collected in 67 circular sample plots, each with 10 m radius. Household survey and focus group discussion was used to gather socioeconomic data. The results indicated that forest management practices that favor coffee production influenced the diversity and evenness of woody species. The non-coffee forest displayed significantly (p = 0.001) higher woody species diversity than coffee-based forest. The Shannon diversity and evenness were 3.23 and 0.79 in non-coffee and 2.00 and 0.52 in the coffee-based forest, respectively. However, the basal area in the coffee-based forest (23.09 m2 ha−1) showed significantly (P = 0.001) higher when compared to non-coffee (13.92 m2 ha−1). The majority (81.4%) of respondents put Ehretia cymosa, Albizia schimperiana and Millettia ferruginea as their first choice in coffee production. Timber and fuelwood extraction for the market is the main factor currently threatening Zege forest. Coffee yield reduction, mentioned by 84.5% of the respondents, owing to seasonal rainfall variability aggravated timber and fuelwood extraction for the market.

Floristic diversity and composition of the Biteyu forest in the Gurage mountain chain (Ethiopia): implications for forest conservation

The Afromontane forests of Ethiopia have been under a serious degradation threat. Assessment of floristic diversity and species composition in Biteyu forest of Gurage mountain chain in the central Ethiopia was conducted to examine the pattern of forest structure. Thirty plots of 30 m × 30 m were used to record the vegetation and environmental data using systematic sampling technique. The local name, plant scientific names, DBH, height, species abundance and percentage canopy cover of plant species were recorded. Shannon diversity index and Sorensen’s coefficients was used for comparison among communities and similar forests in the country. Threats to the forest biodiversity in Biteyu were determined by counting cattle interference and wood stumps as disturbance indicators. Relative Euclidean Distance measures by using Ward’s method (linkage) was applied for cluster analysis. Environmental variables were also recorded in each plot. Woody species population structure, basal area and importance value index were analyzed using spreadsheet programs. Data on species distribution and environmental variables in the forest were analyzed by canonical correspondence analysis. A total of 190 species in 154 genera under 73 families were identified. Twenty species were found to be endemic taxa to the Flora Area. Only three plant community types were identified from the cluster analysis due to the high human influence. The Sorensen’s coefficient showed the resemblance of the Biteyu forest with other Dry Evergreen Afromontane forests in the country. Moreover, altitude and slope strongly affect the species composition and structure of Biteyu forest. Given the high anthropogenic influence, high endemism, high dependence of the local community on the forest resources, forest conservation and restoration measures should be done by stakeholders.

Assessment of wounding factors (natural and anthropogenic) of Juniperus procera and their relation to disease occurrence of Pyrofomes demidofffii in some afromontane forests of Ethiopia

Abstract Wood decay fungus Pyrofomes demidoffii is a cosmopolitan spp. and considered as an important source of damage to Juniperus spp. The aim of the study was to assess the wounding factors of Juniperus procera and their relation to a disease occurrence of P. demidoffii in some afromontane forests of Ethiopia. Disease survey and sample collection was conducted during 2010 in Adaba-Dodola and in Menagesha forests. In Adaba-Dodola forest, sampling was conducted in highly disturbed forest blocks named as non-“WAJIB” and in a relatively undisturbed forest (“WAJIB”) named after the local Afan Oromic language. WAJIB blocks are constitute of Forest Dwellers Association established to protect forest, whereas a non-WAJIB blocks are people living in villages found adjacent to forests with little role in protection of forest. In both study areas, a study quadrat of 20 × 20 m2 within the plot was established at 100 m intervals along a regular grid. In each sampling unit, comprehensive survey was conducted to determine the occurrence of infection by P. demidoffii. About 657 trees (310 in Adaba-Dodola forest and 347 in Menagesha forest) were assessed for the typical signs and symptoms of P. demidoffii. Natural and anthropogenic wounding factors were assessed, and their relationships with disease occurrence of P. demidoffii were determined. Pyrofomes demidoffii was noticed as fruiting bodies and/or white rot on the juniper stands. The disease occurrence of P. demidoffii was significantly higher in juniper stands with a mixed wounding factors followed by wounding by bark-peeling (P

Effects of anthropogenic disturbance on bird diversity in Ethiopian montane forests

ABSTRACT The Afromontane forests of Ethiopia are global biodiversity hotspots, known for their high biological diversity and endemism. However, conservation of these areas is challenging due to increasing human threats, including encroachment of agriculture and settlements, overgrazing of livestock, and selective logging. We examined the effects of forest disturbances on birds, and highlights the potential conservation value of unprotected tropical montane forests for birds in the dry evergreen Afromontane forests of the Bale Mountains, Ethiopia. We sampled birds across 2 yr in both protected forests (characterized by low levels of cultivation, overgrazing, and logging) and unprotected forests (higher levels of disturbance). Using functional traits of birds related to habitat type, diet, and foraging stratum, we characterized the differences between protected and unprotected forests in terms of avian species richness, abundance, and assemblage composition. Overall, species richness was 27% higher and bird...

Fungal community succession and sporocarp production following fire occurrence in Dry Afromontane forests of Ethiopia

Fire is among the main threats to forest ecosystems in Ethiopia and is affecting the forest biodiversity, including fungal communities. This study was aimed to examine the effects of fire on macrofungal taxa richness, diversity and sporocarp production in the Dry Afromontane forests in Ethiopia. Sporocarps were collected from nine plots (100m2) established in one- and ten-year-old burned stands, and in an unburned stands. The data were used to quantify fungal richness and sporocarp fresh weights. Morphological and molecular analyses were used to identify the fungi. Composite soil samples were also collected from each stand and used to determine main edaphic explanatory variables for taxa composition. A total of 61 fungal taxa, belonging to Basidiomycota division were reported, of which 22 were edible. Fungal diversity, richness and sporocarp production were affected just after the fire. Fungal community composition was significantly correlated with Organic matter, P and Ca. Generally, the result is encouraging from the point of view of fungal conservation. It provides novelty information about the macrofungal communities in Ethiopian dry Afromontane forests, likely including many taxa are still unknown to science as well as several edible species which could supply complementary incomes for the rural populations in the study area.

Ecosystem functions and services of cloud afromontane forests in Ethiopia

Using meta data on crop output, crop output together with productivity of animal husbandry, surface water volume, ground water volume and cover of cloud wet afromontane forests in selected four regions which are major food producers in Ethiopia the functions and the services of the forests were modelled. Forest cover significantly and positively explained agricultural productivity, surface and ground water volume in Ethiopia. In similar regression modeling it was determined that food productivity across regions was result of the volume of surface water and ground water. This clearly indicates unwarranted destructive alteration of the forest cover in the country would have unprecedented negative effects thereby exasperating natural disasters which ultimately will cause a negative shock to the overall economy. Furthermore increasing forest cover through the planting of trees and others would have significant positive effect on the economy which enhances the wellbeing of a significant portion of the population in the country. Key Words: Ecosystem Functions, Ecosystem Services, Ethiopia

Edge effects on understory epiphytic ferns and epiphyllous bryophytes in moist afromontane forests of Ethiopia

Abstract Most studies on edge effects in tropical forests have been conducted in landscapes with low human population density and in situations where the edges have been left unused after logging of the adjacent area. Here we studied forest margins heavily used by local farmers in a forest/agriculture mosaic landscape in Ethiopia. We compared forest structure and plant species composition across 41 forest-agriculture ecotones from 200 m out into the agricultural area to 200 m into the forest. There are strong edge effects from the edge and into the forest on canopy cover and number of stumps and apparently these forest-agricultural edges are intensively used by humans. They are penetrated by paths, beehives are found in the trees, timber of various dimensions is harvested and there is sometimes substantial cover of perennial wild (or semi-wild) crops such as coffee and spices. The number of understory epiphytic fern species as well as number of epiphyllous (i.e., growing on leaves) bryophyte species was lower at 20 m than at 75 m from the edge. The number of fern species was higher in newly created edges and thereafter they declined, which indicates an extinction debt. This pattern was not seen for the epiphyllous bryophytes. It is likely that different human management activities are responsible for many of the found edge effects besides wind and sun effects from the edge. Tropical forest margins provide important resources for people in many landscapes. It is important to understand how such use affects the biota of the forests. This study shows that there are substantial edge effects, but that the edge effects do not seem to become worse over time for epiphyllous bryophytes and only slightly so for ferns.

The Role of Communities in Closed Area Management in Ethiopia

Much of the Earth is degraded, is being degraded, or is at risk of degradation. Dry Afromontane forests in Ethiopia are one of the ecosystems affected by this phenomenon. This study focuses on assessment of community perceptions of experiences with, and benefits from, enclosure practices meant to prevent or mitigate land degradation. Communities around Biyo-Kelala and Tiya enclosure areas, in central and northern Ethiopia respectively, were used for the study. The assessment was carried out on the basis of a semi-structured questionnaire survey and focus group discussions. Results showed that an overwhelming majority of the people have a positive attitude about enclosures and feel that they have gained benefits. However, people prefer not to ensure private ownership, but favor maintaining the existing communal (village level) management system instead. This demonstrates that groups emerge to manage common property when they live close to the resource. Yet the issue of benefits and their equitable distribution among community members was found to be the basis for developing a sense of security for ownership and hence the success of enclosures. The other finding was that rehabilitation of deforested lands provides economic benefits by supplying raw material to meet the local demand for wood, reducing the pressure on the remaining forests and supplying various non-timber products. Nevertheless, it is not possible to design a national model for the management of this practice: the design of management rules is specific to a particular locality.

Mycorrhizal status of indigenous trees in dry Afromontane forests of Ethiopia

The dry Afromontane forests in Ethiopia are composed of a number of indigenous tree species. Currently, indigenous trees are declining at an alarming rate in this ecosystem. The few reforestation programs, which have so far been undertaken, employ exotic tree species. This is mainly due to lack of knowledge on the environmental requirements of indigenous trees. Though there have been efforts to solve problems associated with the use of indigenous trees in the reforestation activities, information on the mycorrhizal symbiosis is still lacking. Investigation of roots of 11 indigenous trees, Albizia gummifera, Albizia schimperiana, Aningeria adolfi- friedericii, Croton machrostachyus, Ekebergia capensis, Hagenia abyssinica, Juniperus procera, Podocarpus falcatus, Prunus africana, Olea europaea ssp. cuspidata, and Syzygium guineense, revealed arbuscular mycorrhizal colonization. No evidence of ectomycorrhizal colonization was found. This is the first report on the mycorrhizal status of A. gummifera, A. schimperiana, A. adolfi- friedericii, E. capensis, H. abyssinica, P. africana and S. guineense. The mycorrhizas are characterized by dominantly intercellular hyphal growth, formation of arbuscules on intracellular hyphal branches and low frequency of hyphal coils which can be classified as an Arum-type of AM. The Arum-type of AM is reported for the first time in S. guineense (Myrtaceae), E. capensis (Meliaceae), A. adolfi- friedericii (Sapotaceae) and the gymnosperms J. procera and P. falcatus. Results established that arbuscular mycorrhizas (AM) are predominant in the dry Afromontane forests of Ethiopia. Therefore, AM should receive special attention in indigenous tree seedling production and restoration activities of the dry Afromontane ecosystems of the country.

Seedling populations and regeneration of woody species in dry Afromontane forests of Ethiopia

The composition and density of seedlings, as well as height class distribution of woody species, were studied at two dry Afromontane forests in Ethiopia. A total of 40 species were recorded at Gara Ades and 41 at Menagesha forests. The density was 16 290 and 32 650 seedlings/ha at Gara Ades and Menagesha, respectively. A few species were not represented in the seedling bank, although mature trees were present. This may suggest that the species are under threat of local extinction or ‘that they recruit after major disturbances’. The trend in the height class distribution varied from species to species. However, about 50% of the species showed a negative exponential distribution at both sites, while there were indications of intermittent regeneration in the others. Seedling survival and growth of four species were also investigated, both under shade and in the open, at Gara Ades. The number of surviving seedlings declined progressively during the study period in all the species. Damage and uprooting by animals and people, drought, defoliation by insects and burial by siltation are among the apparent causes of seedling mortality. Mean annual height increment was generally low (< 15 cm) in the four species. Only one of the species showed more rapid height growth in gaps than under shade while the other three species had almost similar growth rates under shade and in gaps. The seedling growth analysis does not support the view that climax species quickly commence rapid height growth after canopy gap develops above them. The results show that in dry Afromontane forests, formation of seedling banks under the forest canopy is the major regeneration route of woody plants, especially climax species.

Effects of ground preparation and microenvironment on germination and natural regeneration of Juniperus procera and Afrocarpus gracilior in Ethiopia

The seedling establishment of Juniperus procera Hochst. ex Endl. and Afrocarpus gracilior (Pilger) C. N. Page was assessed in the Afromontane forests of Ethiopia. Percent light transmission, litter depth and percentage cover of vegetation were assessed for seedling microsites in five sites with different levels and history of disturbance. The response of natural and artificial regeneration to burning, mechanical scarification (removal of all logging waste and ground vegetation) and cultivation following clear felling and timber extraction was assessed 19 months after treatment. There was no evidence that regeneration was correlated with light intensity. Despite the presence of a viable seed bank in the undisturbed forest floor, removal of the overstorey vegetation by clear felling did not encourage natural regeneration of J. procera. This suggests that light may not be the main factor limiting regeneration of J. procera. Natural regeneration of J. procera can withstand exposure and is compatible with management by ‘clear cutting with seeding from adjacent stands’ together with ground treatment, particularly controlled burning which exposes the minearl soil and releases nutrients. In contrast, both clear felling and surface disturbance will discourage the natural (or artificial) regeneration of A. gracilior suggesting that J. procera is a pioneer species which is more exposure-tolerant, whilst A. gracilior is more shade-tolerant and exposure-intolerant.