Spectral radiometric technique for carbon estimation in Omo Forest Reserve, South Western, Nigeria

Abstract

Field-estimated above-ground biomass (AGB) and spectral data from remote sensing were collected from randomly selected 50 sample plots. AGB  was estimated through the biomass density equation. Radiometric measurements were carried out using a set of spectral vegetation indices. The  remote sensing data was calibrated with those obtained from the field using GPS points. The average model-based estimation using satellite image canopy cover was 30.71 t/plot, while the multispectral data was 69.07 t/plot in the biosphere. This gave a difference of 1.44 t/plot and 36.91 t/plot  respectively from the calculated carbon 32.16 t/plot. The canopy cover based estimation deviated from the ground measurement with 1.44 t/plot, while the estimation based on vegetation indices was twice that of field measurement. The result indicated that calibrated field measurements with forest canopy cover from high resolution image was the most reliable remote sensing technique in estimating AGB in a natural forest as compared  to vegetation index. The model selected for a single tree forest based on modified soil adjusted vegetation index with value of 61.18 t/plot compared to the calculated value of 49.84 t/plot may to some extent improve AGB estimation.

Keywords: Carbon sink, Biosphere, Above-ground biomass, Vegetation index and Remote sensing