2020, VOLUME 7 ISSUE 1Pages: 14-19
Estimation of carbon dioxide assimilated in shoot biomass of mature Acacia seyal (Del.) Brenan and Eucalyptus microtheca (F.) Muell
Hasabelrasoul Fadlelmula Mustafa* and Bello Rufa′i Wali
*Faculty of Forest Sciences and Technology, University of Gezira, PO Box 20 Medani, Sudan
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It was determinately proved that CO2 emission has been causing a paramount effect in climate change and hence global warming. The major effort that could mitigate the adverse impact is to expand in the forestation programs. Today, Sudan has lost in two decades (1990–2010) about 6,432,000 hectares of its forests, which significantly reduced the number of surviving trees to absorb CO2. However, Sudan's data on tree species efficiency in assimilating CO2 is limited. Hence, the objective of this study was to estimate the amount of CO2 assimilated by shoot biomass of two tree species widely used in plantation programs in Sudan; Acacia seyal and Eucalyptus microtheca. The non-destructive sampling method of data collection was used in this research in November 2016, when all the trees held their leaves. That was in Umbarona Forest for A. seyal and Alamelhuda Forest for E. microtheca, both in the vicinity of Medani Town in central Sudan. One hundred samples of rectangular layout were randomly selected for each species. The diameter at breast height (cm) and total tree height (m) were measured. A recommended procedure to estimate green shoot biomass (kg) and sequestered CO2 (kg) was adopted. Accordingly, the green biomass weight was estimated on the basis of the formula; W = 0.25 D2H for D< 11 cm and W = 0.15 D2H for D > 11 cm. Two models correlated the diamter at breast height (DBH) and height (h) of the trees to the weight of CO2 sequestered (wcs). A. seyal had the highest magnitude of sequestered CO2 as it was estimated at 370 ton/hectare, and that for E. microtheca was 176 ton/hectare. The correlation analysis applied to test the significance of two models (wcs = a + b.h and wcs = a + b.DBH) on the estimated amount of CO2 sequestered in both species revealed that the model wcs = a + bDBH was the best predicting model as it retained 93% of the coefficient of determination (R2) for E. micotheca and 68% for A. seyal. In conclusion, A. seyal was the most efficient in CO2 sink, despite the fact that it is a deciduous tree while E. microtheca is an evergreen tree. However, if the felling cycle will consider, six year for E. micotheca and 20 years for A. seyal and E. microtheca will be the most efficient in CO2 sink. The diameter at breast height was the most interpreting biophysical parameter for assimilated CO2 stock estimation. Establishing more forest plantations, supporting forestry agencies, implementing strong policies and improving public awareness on forest conservation as a natural carbon sink are recommended.