Woody Species Composition, Structure, and Carbon Stock of Coffee-Based Agroforestry System along an Elevation Gradient in the Moist Mid-Highlands of Southern Ethiopia

Abstract

There is a limited effort in Ethiopia to study scientifically the ecological features of traditional coffee-based agroforestry systems. This study was initiated to determine the structure, composition, and carbon stock of woody species along an elevation gradient of a traditional coffee-based agroforestry system in Yirgacheffe district, southern Ethiopia. Woody plants’ inventory was conducted in thirty-eight sampling quadrats (20 ∗ 20 m) along five elevation contours and eight transects. Thirty-eight soil samples were taken from randomly selected subplots at 0–30 cm soil depths. In this study 32, woody plant species representing 23 families were recorded. Species richness ranged from 13–17 along the elevation gradient. Woody plant diversity indices appear to have a slight variation with increasing elevation gradient. Shade tree and coffee shrub density, DBH, and height showed significant variations along the elevation gradient. Total aboveground woody biomass carbon stock along elevation gradient ranged from 11.07 to 27.48 Mg·ha−1. Soil organic carbon stock was slightly different across elevation gradients with a mean range of 83.91 to 89.29 Mg·ha−1. These indicate that the agroforestry system has significant potential of storing and enhancing ecosystem carbon stocks across all the elevation gradients. The findings generally show that agroforestry systems in the study area are diverse, structurally complex with significant carbon storage in the soil and woody biomass.

Woody Species Diversity, Structure, and Management of Parkland Agroforestry along Agroecology: The Case of Tembaro Special District, Central Ethiopia

“…Variation in woody species richness between the highland, and midland might be due to soil type, socioeconomic factors, and farmers' preferences to plant or retain trees/shrubs in their farmlands. This is in agreement with finding of [18] who revealed that environmental conditions, and farmers' tree planting activities can affect species richness between different geographical locations. The extent of human and livestock disturbance could made the difference in woody species diversity conservation between the highland, and midland parklands.…”

“…The low number of individuals in the lower diameter classes across altitudinal gradients might be selective removal of trees, and shrubs from the farmlands, higher human and animal disturbances causing poor regeneration of trees, and lack of seedlings to plant in the parkland agroforestry. This is in line with finding of [18,46] who stated that removing shade trees from coffee-based agroforestry to reducing completion results the low number of individuals in the lower diameter classes in Southwestern Ethiopia. The J-shape indicates unstable natural and artificial regeneration of woody species in the midland parkland agroforestry.…”

Socioeconomic and biophysical factors affect tree diversity in farms producing specialty coffee in Caranavi, Bolivia

“…Our results express higher tree density (610 trees ha − 1 ) compared with Nicaragua, Costa Rica and El Salvador, where density ranks between 198-488 trees. However, Ethiopian CAFS density ranks higher (631-2213 trees ha − 1 ) than our results(Tesfay et al 2022). The reasons that explain observed differences might relate with farm management, as studies in Mexico and Ethiopia found that tree diversity and structural complexity decrease with increasing management intensity(Moguel & Toledo 1999;Worku et al 2015).…”

“…Trees' importance on CAFS species composition was weighted using IVI (importance value index). IVI sums relative values of frequency, density, and dominance (through basal area), so species having highest IVI are considered more dominant (Tesfay et al 2022).…”

Response of Different Coffee-Based Agroforestry Management on Microbial Respiration and Density

“…Coffee-based agroforestry has been recognized as a land use system that provides ecological and economic benefits (Waktola and Fekadu 2021). The system structures resemble natural forests; thus the potential for biodiversity and soil conservation and maintaining yield for food security in coping with climate change (Tesfay et al 2022). Coffee-based agroforestry creates a suitable microclimate (humidity and temperature) as shading for coffee and for soil organism habitats (Asfaw and Zewudie 2021).…”