Assessment of carbon sequestration of Teak (Tectona grandis Linn. F.) plantation on the campus of University of Ilorin, Nigeria

Abstract

The study assessed the carbon sequestration of Tectona grandis Linn. F. in five age series (11-15 years old), at the University of Ilorin, north-central Nigeria. Data were collected using a stratified sampling technique and twenty square plots of 25 m × 25 m were laid. A non-destructive method was used to determine the biomass of the trees. Tree enumerations were carried out for diameters at the base, top, middle, diameter at breast height (DBH), and height. Soil samples at two different depths (0-15 cm and 15-30 cm) were collected and analyzed to obtain soil organic carbon. The results were summarized using descriptive statistics, while the relationship between tree growth variables and carbon stock was assessed using correlation and regression analysis. The results showed that tree carbon stocks were 230.05 t ha-1, 362.35 t ha-1, 277.48 t ha-1, 216.40 t ha-1, and 126.20 t ha-1 for 11 years old (2012), 12 years old (2011), 13 years old (2010), 14 years old (2009) and 15 years old (2008) age series, respectively. The soil organic carbon stocks were 1.1025 t ha-1, 0.6253 t ha-1, 1.2019 t ha-1, 1.4070 t ha-1 and 0.7615 t ha-1 for 11 years old (2012), 12 years old (2011), 13 years old (2010), 14 years old (2009) and 15 years old (2008) age series, respectively. The study also revealed that the 14-year-old (2009) age series had the highest carbon stock, and the total carbon stock estimate was 151,850.84 t. The potential cash value of the carbon stock was also estimated at $91,894.40 t C ha-1 and the total PCV was $56,606,951.50. Correlation analysis showed a strong positive correlation between most of the growth variables and carbon stock. The regression equation (Y = -596.48 + 27.16 THT + 1238.34 DBH, Adj R2 = 82.7%) showed that DBH and height of trees are suitable for evaluating the carbon stock in the study area.