Carbon Sequestration and Linear Models for Individual Tree Biomass Estimation in Bebi Mixed Forest Plantation, Cross River State, Nigeria

Abstract

The study developed allometric models for estimating aboveground biomass for Tectona grandis and Gmelina arborea in Bebi Mixed Plantation, Cross River State, Nigeria. Simple random sampling technique was used to lay a total of twenty sample plots; six sample plots for Gmelina arborea and fourteen sample plots for Tectona grandis. A total of 606 individual tree species were measured for total height and diameter at breast height (DBH). DBH, total height and specific wood density of each tree species were fitted into allometric equations to determine the green aboveground biomass of each tree species. Gmelina arborea, mean diameter at breast height, total height and aboveground biomass of 25.2 cm, 11.1m and 40.3kg respectively were obtained. Mean basal area of 18.6m2ha-1 was obtained with a mean volume of 40.2629m3ha-1. The mean stand level green biomass was determined to be 96.65777 tons/ha-1 while mean dry stand level dry biomass was 70.07686 tonha-1 and stand level means of carbon stock and carbon-dioxide emission were 35.03843 tonha-1and 128.5911 tonha-1 respectively. Meanwhile, for Tectona grandis, mean diameter at breast height, total height and aboveground biomass of 16.4 cm and 13.8 m and 35.8kg respectively were obtained. Mean basal area of 25.61m2ha-1 was obtained with a mean volume of 64.1082m3ha-1. The mean stand level green biomass was determined to be 108.4855 ton/ha-1 while mean dry stand level dry biomass was 78.6519 tonha-1 and stand level means of carbon stock and carbon-dioxide emission were 39.3259 tonha-1and 144.3264 tonha-1 respectively; each developed models were correspondingly validated Permanent sample plots should be established in the plantation to enhance monitoring and evaluation.