Woody species diversity and carbon stock under different land use types at Gergera watershed in eastern Tigray, Ethiopia

Woody diversity and carbon stock estimation of land use types have critical role for the successful implementation of climate change mitigation and adaptation strategies. This study investigated relationships between woody species diversity and carbon stock in different land use types. Three land use types (area exclosure, homestead agroforestry and woodlot) were selected in the Gergera watershed, Tigray, Ethiopia. A total of 45 sample plots were established using stratified random sampling, 15 plots in each land use types. Vegetation parameters such as diameter at breast height, diameter at stump height, tree height and species type were recorded. Woody species diversity and carbon stocks significantly varied among the land use types. Woody species diversity, species richness and species density were significantly higher in exclosure compared to the other land use types. Mean above-ground woody species carbon stock in woodlot (8.79 ± 7.72) was significantly higher than both in exclosure (2.29 ± 2.73) (p = 0.002) and homestead agroforestry (4.17 ± 4.18) (p = 0.022) and similarly had higher below ground woody species carbon stock than the other two systems. However, there were no significant difference among exclosure and homestead agroforestry in total carbon stock. There were a significant relationship between woody species diversity and carbon stock (R2 = − 0.349, p = 0.019) in each land use types. Land-use change can lead to changes in species diversity and significantly contribute to carbon sequestration. Although, more carbon stock was found in woodlot dominated by Eucalyptus, this would result in water competition and other fast growing trees may be preferable.