Abstract
Forests play a significant role in climate change mitigation by sinking and storing more carbon. The main objective of the study was to estimate the role of protected area forests in the reduction of atmospheric carbon dioxide by conducting studies on two national parks: Chebera-Churchura(CC) and Borena- Sayint(BS). The study includes exploring vegetation characteristics, estimation of total carbon stock density, and assessment of land cover changes for the periods of 1990,2003, and 2017. A stratified random sampling design was used in this study.
The stratified lands are Moist Afromontane forest, Combretum Terminalia, Wooded grassland and Wetland land cover types for CCNP while, Dry Afromontane forest, Afro-alpine woodland, and Afro-alpine grasslands are those land cover types for BSNP. Data was collected for Above ground biomass, Deadwood biomass, Litte biomass, Soil organic matter, and Land cover change analysis. Biomass data were collected from 130 and 63 big plots of 2000m2 for CC and BS respectively. Litter biomass data were collected from all the 1m x1m small subplots framed within the big plot on the field and an evenly mixed 100g of the sample was taken for laboratory analysis. Deadwood data was collected from the big plot for woods with DBH ≥ 10cm. For SOC analysis, from the two 1m x 1m small subplot with two layers of soil depth(0-30cm and 30-60cm), 60 and 40 samples of 150g were collected for soil composite in CC and BS respectively. Similarly,, for soil bulk density determination 60 and 40 samples from the 1mx1m small subplot with two layers were collected by core sampler for CC and BS respectively. For the above and below-ground biomass estimation, DBH and height of trees in the big plot with DBH ≥ 5 cm were measured. Above-ground biomass was estimated by using allometric models of having et al(2014) while below-ground biomass was taken 26 % of Above ground biomass. Litter biomass was analyzed by the loss on ignition method. However, soil organic carbon was analyzed by Walkley & Black (1934) while soil bulk density was analyzed by the wet oxidation method. For data summarization and analysis Microsoft excel 2016, SPSS software version 23, Q GIS version 2.1.8, and 3.2.3 as well as Arc GIS 10.3 were used in this study. The mean and standard deviation were used to test the relation between variables. One way ANOVA was used to test the effect of land cover variation on biomass carbon stock. But, Univariate analysis of the generalized linear model was used to test the effects of land cover and soil depth on soil carbon stock. The mean total carbon stock in CCNP was 854.41 t ha -1 (Table: 6). Similarly, The mean total carbon stock in BSNP was 950.59 t ha -1 (Table: 6). The result of LCC analysis showed that in both study sites the grassland has been increased at an average rate of 1,089.18 ha/year; while the woodland, forest land and COGL area in the same sites were decreasing at an average rate of 1,604.36, 181.21 and 73.38 ha/year, respectively; during the last 27 years. Despite the rapid decline in the woodland and forest land coverage, the present study points out forests in BS and CCNP have the potential to sequester plenty of CO2 with a considerable variation in land use type and soil depth.
Keywords:-Forests, Climate change mitigation, Carbon sinking, Carbon storing, carbon pools, Biomass carbon, Soil organic carbon, Protected area.
