Abstract:
Agroforestry systems, which integrate trees with crops and/or livestock, play a crucial role in
enhancing biodiversity, promoting sustainability, and sequestering carbon to combat climate
change. Understanding the ecological and carbon storage potential of these systems can
support sustainable land management and climate change mitigation strategies. This study
investigated woody species diversity and aboveground live carbon storage within
agroforestry systems of Tarcha Zuria district, Dawuro Zone, Southwest Ethiopia.
Agroforestry systems were stratified into three land use types: homegarden, cropland, and
pastureland. Four transects, each 14 km long and 1 km wide on either side, were laid across
the different land-use types at regular intervals. A total of 42 sample plots were established
along transicts sysematically with 14 plots in each land use type. Vegetation parameters,
including diameter at breast height (DBH), height, and species type were recorded. The data
analysis used structural (height, DBH, and basal area) and compositional (frequency,
diversity, and density) parameters. Data were analyzed using past software with descriptive
statistics for the Shannon-Wiener diversity index and Sorenson’s similarity index.
Aboveground live biomass (AGB) of woody species with DBH ≥ 5 cm was calculated using
the updated nondestructive allometric equation: AGB = 0.0673(ρD2H) 0.976. Aboveground
carbon (AGC) was estimated as 50% of AGB. One-way analysis of variance (ANOVA) was
used to test the differences in AGC across land use types, followed by Tukey’s HSD test for
mean comparisons. A total of 62 woody species belonging to 28 families and 46 genera were
recorded and documented across 42 sample plots. Similarities in species composition were
higher between home garden and cropland (77%) and lowest between cropland and
pastureland (49%). Woody species diversity and carbon storage varied significantly among
the land use types. Woody species diversity, species richness, and species density were
significantly higher in pastureland, while species evenness was greater in cropland
compared to the other land use types. The AGC stored in homegarden (19.15 t/ha) was
significantly higher than both in cropland (7.87 t/ha) and pastureland (6.35 t/ha). The
variation in carbon storage among different land use types was statistically significant (F =
77.728, P = 0). Finally, the study demonstrated that woody species in the various
agroforestry systems play a key role in carbon sequestration. Their conservation is therefore
recommended to sustain this benefit.
