3rd World Congress on GIS and Remote Sensing
Charlotte, USA
Muluken N. Bazezew
Dilla University, Ethiopia
Title: Integrating Airborne liDAR and Terrestrial Laser Sanner derived forest parameters for accurate estimation of above-ground biomass/carbon in Ayer Hitam tropical forest reserve, Malaysia
Biography
Biography: Muluken N. Bazezew
Abstract
Parameters of individual trees can be measured from Airborne LiDAR scanner (ALS) point cloud data provided that the laser point is dense enough and trees in multiple canopy layers are visible from the top. However, retrieving tree parameters in a complex biophysical environment of tropical forests using single LiDAR technology could still be inadequate. This paper presents new approaches of acquiring tree parameters for estimating above-ground biomass (AGB) through integrating ALS and Terrestrial laser scanner (TLS). ALS data was used to detect and extract upper canopy tree parameters while TLS complemented for tree stems and lower canopy trees height measurements. Initially, multi-resolution segmentation of ALS canopy height model (CHM) was executed to delineate individual tree crowns of upper canopy trees. The result showed segmentation accuracy of 73% and 1:1 correspondence of 78% with the reference tree crowns. About 62% of trees were delineated from ALS-CHM while the remaining lower canopy trees were identified from TLS data. ALS detected trees were then co-registered and linked with the corresponding tree stems detected by TLS for diameter at breast height (DBH) use; 93.5% of the field recorded trees were recognized from TLS data for DBH measurements. DBH derived from TLS was validated using manually measured-field DBH, and coefficient of determination (R2) of 0.989 and root mean square error (RMSE) of 1.30 cm (6.52%) were achieved. Two-way tree height validations were implemented; upper and lower canopies tree heights. The R2 and RMSE between field and ALS-measured upper canopy trees height were found to be 0.61 and 3.24 m (20.18%), respectively. R2 of 0.69 and RMSE of 1.45 m (14.77%) were achieved between field and TLS-based lower canopy trees height. The AGB or carbon regression model that the relationship between AGB derived from remote sensing (ALS + TLS) and traditional field method at the plot level resulted in R2 of 0.97 and RMSE of 0.62 Mg (7.64%) where field method underestimates with the bias of –0.289 (–3.53%) Mg