Semi-forest coffee cultivation and the conservation of Ethiopian Afromontane rainforest fragments

Abstract

a b s t r a c tCoffea arabica shrubs are indigenous to the understorey of the moist evergreen montane rainforest of Ethiopia. Semi-forest coffee is harvested from semi-wild plants in forest fragments where farmers thin the upper canopy and annually slash the undergrowth. This traditional method of coffee cultivation is a driver for preservation of indigenous forest cover, differing from other forms of agriculture and land use which tend to reduce forest cover. Because coffee farmers are primarily interested in optimizing coffee productivity, understanding how coffee yield is maximized is necessary to evaluate how, and to what extent, coffee production can be compatible with forest conservation.Abiotic variables and biotic variables of the canopy were recorded in 26 plots within 20 forest fragments managed as semi-forest coffee systems near Jimma, SW Ethiopia. In each plot, coffee shrub characteristics and coffee yield were recorded for four coffee shrubs. Cluster and indicator species analyses were used to differentiate plant communities of shade trees. A multilevel linear mixed model approach was then used to evaluate the effect of abiotic soil variables, shade tree plant community, canopy and stand variables, coffee density and coffee shrub size variables on coffee yield.Climax species of the rainforest were underrepresented in the canopy. There were three impoverished shade tree communities, which differed in tree species composition but did not exhibit significant differences in abiotic soil variables, and did not directly influence coffee yield. Coffee yield was primarily determined by coffee shrub branchiness and basal diameter. At the stand level a reduced crown closure increased coffee yield. Yield was highest for coffee shrubs in stands with crown closure less than median (49 ± 1%). All stands showed a reduced number of stems and a lower canopy compared to values reported for undisturbed moist evergreen montane rainforests.Traditional coffee cultivation is associated to low tree species diversity and simplified forest structure: few stems, low canopy height and low crown closure. Despite intensive human interference some of the climax species are still present and may escape local extinction if they are tolerated and allowed to regenerate. The restoration of healthy populations of climax species is critical to preserve the biodiversity, regeneration capacity, vitality and ecosystem functions of the Ethiopian coffee forests.

Effect of Dominant Shade Trees on Coffee Production in Manasibu District, West Oromia, Ethiopia

“…Higher Available Potassium (4.98) was from C. africana (Table 2). Inline of the current study the earlier finding of Aerts et al (2011) from south west Ethiopia shown higher pH, per cent N and Carbon from M. ferruginea; higher Cation exchange capacity and potassium from C. macrostachyus; higher Phosphorus from and A. gummifera, respectively.…”

“…However, higher coffee weight (237.99 g/1000 bean) and bean yield (3.09 Mg ha -1 ) were observed under C. macrostachyus (Table 2). Similarly, earlier studies also confirm the relative higher yield under Millettia ferruginea (Aerts et al, 2011) and significantly highest under A. abyssinica (Kufa et al, 2007). Such variation may caused from soil organic matter, total nitrogen and organic carbon provided by the plants (Kufa et al, 2007;Aerts et al, 2011).…”

“…Similarly, earlier studies also confirm the relative higher yield under Millettia ferruginea (Aerts et al, 2011) and significantly highest under A. abyssinica (Kufa et al, 2007). Such variation may caused from soil organic matter, total nitrogen and organic carbon provided by the plants (Kufa et al, 2007;Aerts et al, 2011). C. macrostachyus leads coffee production to be better due to having good litter.…”

“…Accordingly, C. macrostachyus was found the most contributing tree from the current study area. Whereas it was estimated to be higher under the shade of A. abyssinica (Kufa et al, 2007) and M. ferruginea (Aerts et al, 2011) from south west Ethiopia. Their importance for coffee production has discussed in association to modification of the microclimate, decomposition from the litter fall in building soil fertility, intercepting half of the incoming light intensity (Kufa et al, 2011).…”

Conservation of the Ethiopian church forests: Threats, opportunities and implications for their management

“…S1-S4) and local people rely on these church forests for the provisioning of livestock feed, tree seedlings, fuelwood, honey, clean water and other essential ecosystem services including shade, climate regulation, habitat for pollinators and spiritual values (Cardelús et al 2012;Amare et al 2016). In the southwest of the country, shade coffee cultivation has, until now, guaranteed that more or less natural forest remained an important land cover (Tadesse et al 2014), despite the clear trade-off between coffee productivity and forest ecological quality (Senbeta and Denich 2006;Schmitt et al 2010;Aerts et al 2011;Hundera et al 2013). In the central and northern Ethiopian highlands, however, high historical land use pressure has resulted in widespread deforestation and land degradation (Darbyshire et al 2003;Nyssen et al 2004).…”