Abstract:
The study was conducted in Deder District of Obi forest, with the objectives of assessing the
woody species diversity, composition and estimating of the carbon stock of the forest. A
systematic sampling method was used to conduct the vegetation sampling. In order to collect
vegetation data, a total of 36 quadrats, each with the size of 20 m x 20 m for tree, 5 m x 5 m for
shrubs at an interval of 100 m, were laid along altitudinal variation. Aboveground biomass was
estimated by using allometric models while belowground biomass was determined based on the
ratio of belowground biomass to aboveground biomass factors. For litter and soil sample
collection, five sub-quadrats each with the size of 1 m x 1 m were established at four corners and
center of every quadrat. Plant Species Diversity analysis was carried out by using Shannon
Weiner index. SPSS software version 20 was used to analyze the data. The study of woody plant
species in Obi forest shows a total of 22 species from 16 families and 20 genera were identified
in this study. Juniperus procera was the dominant species counting 243 trees, and Cupressus
lucitanica and Olea africana were the second and third dominant species recorded with 207 and
99 trees respectively. The value of Shannon –Wiener Diversity Index (H’) of the whole vegetation
of this study area was 2.29 with the evenness or equitability value (J= 0.74). From the analysis
of dif erent carbon pool, the total mean carbon stock of the forest was 232.935 t ha 1 whereas
aboveground carbon stock share 60.82 t ha 1
, belowground carbon stock 15.814 t ha 1
, litter
carbon stock was 2.49 t ha 1 and soil organic carbon (SOC) 153.8 t ha 1
. Carbon stocks
variation along altitude showed that all carbon pools were not significant at (p<0.05) along
altitudinal gradient. Analysis of correlation of carbon stock with species diversity was done
using linear regression. Accordingly, aboveground biomass carbon stock and species diversity
had weak positive correlation (R = 0.049). Similarly, the below ground, litter and soil carbon
stock had also weak correlation with species diversity (R = 0.049 R =0.006, R = 0.052
respectively). So as to improve the ecological function of the forest, the community, government
of ices and non-governmental organization should jointly work in forest conservation and
management. People around the forest is still cutting tree for fire wood and putting the forest in
danger, the introduction of alternative energy sources is recommended to the area to reduce
impact on the forest as well as to increases the diversity of the forest and its carbon stock
potential
