Estimation of carbon stocks of woody plant species in church forests of West Gojjam zone, Northwestern Ethiopia: Implications for climate change mitigation

Abstract

Forests, particularly church forests, play a crucial role in mitigating climate change by absorbing and storing CO₂, preserving biodiversity, and acting as carbon sinks. This study aimed to estimate the biomass and carbon stocks of various woody species in church forests in the West Gojjam zone. Twenty-six church forests were selected based on agroecology, elevation, size, and proximity to population centers. Vegetation data were collected using a systematic sampling technique, with 20 m x 20 m (400 m²) plots established along transect lines oriented at 120° intervals at 60°, 180°, and 300° within each church forest. Measurements of diameter at breast height (DBH) and height were taken for all matured woody plants with a DBH ≥ 2.5 cm. Data analysis was performed using one-way ANOVA to evaluate the effects of altitude, forest size, and human disturbance on aboveground biomass (AGB) and carbon stocks. Additionally, linear regression was applied to investigate the relationship between vegetation structure (species richness, density, and diversity) and biomass accumulation. The results revealed a total of 111 woody species, dominated by indigenous species particularly from the Fabaceae family. The study church forests had Shannon diversity index and richness ranging from 1.73 to 3.47 and 7 to 45, respectively. The results showed that the 26 church forests had an average aboveground biomass (AGB) of 31.97 ± 3.31 tons ha^-1 and a CO₂ equivalence of 97.15 ± 10.47 tons ha^-1. The AGB and aboveground carbon (AGC) values varied among the church forests, of which Debre Mihret Mesk Kidanemihret had the highest AGB with 99.00 tons ha^-1 and 49.50 tons ha^-1 AGC, indicating their substantial capacity for carbon storage. Conversely, Korch Silassie church forest displayed the lowest AGB, suggesting ecological challenges that necessitate targeted conservation efforts. These findings underscore the critical role of church forests as carbon sinks, capable of sequestering atmospheric CO₂ and contributing to the mitigation of climate change. The findings of the present study suggest the integration of church forests into national and international climate policies, such as REDD+ to leverage their potential in reducing emissions from deforestation and forest degradation.