Farmer-led approaches to increasing tree diversity in fields and farmed landscapes in Ethiopia

Agroforestry Systems - Increasing tree cover and managing trees better on farms in Ethiopia supports livelihoods and the environment but most tree-planting schemes promote only a few species. This...     

Understanding patterns of tree adoption on farms in semi-arid and sub-humid Ethiopia

Trees on farms are a widespread feature of landscapes across a large part of Ethiopia with an important role in enhancing the resilience of smallholder livelihoods through the provision of ecosystem services. Despite their importance, little is known about what trees are planted or retained from natural regeneration by different types of farmers that results in the pattern of tree cover found in the region. We address this knowledge gap through analysis of household survey data from semi-arid and sub humid areas of Oromia regional state. A set of composite variables that represent distinctive patterns of tree cover on farms were derived from principal component analysis and Pearson correlation analysis. This revealed two major tree adoption strategies: farmer managed natural regeneration (FMNR) of trees to meet subsistence needs as well as contributing to other ecosystem services; and, high value agroforestry (HVAF) involving planted trees used largely to produce fruits, timber and fodder. Regression analysis further identified fine-scale variation in ecological and socio-economic factors that affect which of these two broad strategies are adopted by farmers. Favorable climatic conditions coupled with institutional arrangements to control free grazing were pre-conditions for HVAF, whereas poor biophysical potential and sloping land provided a positive incentive for farmers to adopt FMNR. Farmers with preferences for tree species with multiple utilities and locational flexibility favored FMNR while adoption of HVAF was more asset-driven. Our findings reveal that farmers integrate many native and exotic tree species on their farms to meet their variable farm conditions, needs and asset profiles in stark contrast to most tree promotion efforts that focus on a few, usually exotic, tree species. We recommend that future agroforestry promotion should embrace a diversity of tree species appropriate to matching the fine scale variation in ecological conditions and farmer circumstances encountered in the field.     

Genecological zones and selection criteria for natural forest populations for conservation: the case of Boswellia papyrifera in Ethiopia

Rapid changes in land-use in the Combretum–Terminalia woodlands of northwestern Ethiopia are mainly due to the increases in commercial farming and immigration.We used integrated ecological and social data collection techniques,including subdivision of the vegetation zone,vegetation survey,focus group discussions and key informant interviews,to identify genecological zones and set criteria for selection of viable populations of Boswellia papyrifera(Del.)Hochst in Ethiopia for conservation.Interviews of senior experts were supported with a rating method and involved 43 respondents and focused on identifying and weighting criteria and indicators of selection in a participatory way to prioritize populations for conservation.Using mean annual rainfall data,we reclassified the Combretum–Terminalia woodland vegetation region into three moisture zones(wet,moist and dry),and designated them as genecological zones for B.papyrifera conservation.A total of 35 woody species were identified at Lemlem Terara site in Metema district,and the Shannon diversity index and evenness were 2.01 and of 0.62,respectively.There were 405 adult trees,and 10 saplings and3314 seedlings per ha.The trees were medium-sized with overall mean diameter at breast height(dbh) of 16.9(±9.5)cm.Seedling recruitment was poor due to grazing,crop production and fire incidences.Through a multi-criteria decision analysis,five criteria and 20 quantitative indicators were identified and weighted to prioritize populations for conservation.These criteria in their descending order of importance are(1) forest ecosystem health and vitality,(2)forest cover and population structure of B.papyrifera,(3)productive function of the forest,(4) biological diversity in the forest,and(5) socioeconomic benefits of the forest to communities.Multivariate tests in the general linear model revealed significant differences among researchers and nonresearchers in rating the criteria and indicators,but not among foresters and nonforesters.Hence,participatory multi-criteria decision analysis should involve people from various institutions to rectify decisions on conservation of the species.Careful evaluation of the investment policy environment and engaging those government bodies that are responsible to allocate the dry forests for commercial farming is recommended before the proposed criteria are applied to select populations for conservation,thus ensuring subsequent use of the outcomes of such exercises and better reconciling conservation and agricultural production increment goals.     

Variation in seed traits and seedling vigour of <Emphasis Type="Italic">Cordia africana</Emphasis> Lam. provenances in Ethiopia

Cordia africana is a very important indigenous tree species for timber and other products and services in Ethiopia. Seed traits and seedling vigour of seeds from 12 provenances of the species were compared. Mean seed mass for each provenance was assessed for 1000 seeds in 10 replications, and seed length and width were measured for 100 seeds in four replications per provenance. Germination was assessed in a glasshouse taking 400 seeds from each provenance. Root collar diameter and height of 440 seedlings grown in a nursery for 290 days in Addis Ababa were measured. Seed length, seed width, seed mass, and shoot height and root collar diameter of seedlings showed significant differences (P < 0.001) among provenances. Correlation analysis between seed and seedling traits and environmental variables revealed significant positive correlations between seed width and germination percentage, seed width and altitude, seed width and longitude and seed length and latitude. Negative correlations were obtained between seed width and temperature, seed width and rainfall, seed mass and temperature, and germination and temperature of the seed source. As expected, differences in seed trait did not explain the variability in seedling vigour. Determining quantitative variations in seed traits and seedling vigour among provenances and the patterns along environmental gradients are essential for informing decisions on the tree improvement programme of the species.