Sensitivity of Above-Ground Biomass to Terrestrial LIDAR-Derived Tree Height in Berkelah Tropical Rainforest, Malaysia

Abstract

Tree height can be derived from airborne and terrestrial LIDAR in a nondestructive way. This study aims to analyze and investigate whether above-ground biomass (AGB) is sensitive or not to tree height derived from terrestrial LIDAR point cloud data in Berkelah tropical rainforest, Malaysia. To select the unit of analysis, a non-probability sampling of which purposive sampling approach was adopted. Accordingly, 32 sample plots were measured and scanned during the field data collection. Upper and lower canopy trees height was derived from airborne and terrestrial LIDAR, respectively. Moreover, terrestrial LIDAR was used to derive DBH of all upper and lower canopy trees. DBH measured in the field was used to validate the DBH manually derived from terrestrial laser scanner (TLS) point cloud data. To calculate AGB of both lower and upper canopy trees, the DBH derived from TLS point cloud data was used. The coefficient of determination R2 and RMSE of the DBH manually derived from TLS point cloud data validated by field measured DBH were 0.99 and 1.37 cm, respectively. This result revealed the existence of almost one to one relationship and based on the statistical test undertaken; there is no statistically significant difference between the two DBH measurements. Moreover, for sensitivity of AGB, when TLS tree height was validated by corresponding trees height from airborne LIDAR, 0.72 and 2.42 m were found for R2 and RMSE, respectively. Based on the findings, AGB is not sensitive to tree height derived from terrestrial LIDAR point cloud data.