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Background Forests provide various ecosystem services. They are natural capitals that enhance nature to regulate itself via carbon sinks. However, anthropogenic and natural factors have altered their CO2 sequestration and carbon storage potentials. This study is aimed for examining the effect of patch size and biomass extraction on carbon stocks in northern Ethiopia. A total of 61 sample plots measuring 20 m × 20 m size each (0.04 ha) had been systematically assigned on patches classified into three size categories. However, the numbers of plots taken per patch were different with their sizes. Moreover, stump density has been computed at each plot to estimate the difference in the level of disturbance among patches. Carbon stocks had been estimated via models previously developed. One-way ANOVA was used to examine a variation in carbon stocks and sequestration potentials. Besides, a linear regression analysis was discretely done to examine the relationship between patch sizes, disturbance level, and carbon stocks. Results The overall aboveground biomass (ton ha−1) for the studied patches was 2059.13. There was a statistically significant variation in carbon stocks (ton ha−1) among patch size categories. The mean levels of disturbance ranges from 10.83% ± 1.30 to 30.8% ± 4.04. However, statistically significant difference in the level of disturbance was observed between large and small patch size categories, respectively (p < 0.05). Besides, a regression analysis confirmed a significant and negative relationship between patch size and patch disturbances (R2 = 0.65, p < 0.05). However, significant positive relation between carbon stocks (ton ha−1) and patch size (R2 = 0.53, p < 0.05) had observed. Conclusions In general, patch size and biomass extinction significantly influenced carbon stocks and CO2 sequestration potentials of forests. Consequently, with the pressing need to mitigate the effects of rising atmospheric CO2, maximizing carbon storage in the forest ecosystem is increasingly considered a viable management strategy. Therefore, disturbed land restoration, increasing forest patch size, sustainable management, and conservation of the existing remnant forest patch is needed to enhance carbon stocks and CO2 sequestration potentials.

The study was conducted in the Harego dry Afromontane forest, Northeastern Ethiopia, to analyze woody species composition, diversity, structure, and regeneration status. To collect the vegetation data, a total of 67 sample plots measuring 400 m 2 20 m × 20 m were laid systematically. Species identity, abundance, height, and diameter at breast height (DBH) were recorded for each sample plot. Diversity, structural, and regeneration status were analyzed for the forest. A total of 50 woody species representing 35 families and 44 genera were identified and recorded. According to the IUCN Red List Category, Rhus glutinosa A. Rich and Prunus africana (Hook.f.) Kalkm. are vulnerable species. Fabaceae was the dominant family, and of the total species, 27 were shrubs, 19 were trees, and 4 were climbers. The species accumulation curve indicates that the majority of plant species in the study area were captured by our sampling efforts. The values of true Shannon (N1 = 17) and true Simpson (N2 = 11) indicate that species in the Harego forest are more or less evenly distributed. The abundance-frequency ratio of all woody species (WI = >0.05) indicates the heterogeneity of species composition. The total density and basal area were 4400 stems ha−1 and 9.66 m2 ha−1, respectively. The majority of the species fallen into the lower IVI classes. The diameter and height class distribution revealed an inverted J-shape. The increase in population demand and disturbance shows a high variation in stand structure and hampered natural regeneration, which needs immediate conservation actions.