Estimating Above Ground Biomass for Eucalyptus Plantation Using Data from Unmanned Aerial Vehicle Imagery

摘要

The fast-growing Eucalyptus trees are important for a renewable energy source, carbon storage as well as the variety of industry. For Eucalyptus tree plantation inventory and monitoring, Canopy Height (CH) and Above Ground Biomass (AGB) are required parameters. However, the traditional inventory methods are label intensive, time-consuming, and inaccurate. This study, we presented the method for estimating CH and AGB from Eucalyptus plantation based on the very high spatial resolution imagery (-5 cm.) from Unmanned Aircraft Vehicle (UAV). To estimate AGB, we first generated the digital surface models (DSMs) from 3 D point-cloud. Then, the digital terrain models (DTMs) were generated from Real Time Kinematic (RTK.) Differential Global Positioning System (DGPS) surveying technique. The CH was calculated based on the different of DSM and DTM. We located individual trees location using tree detection software. Next, the allometric equation was generated from the 20 samples (tree) and their subsamples (e.g. foliage, litter, branch). The correlation between sampling tree height and tree weight was relatively high (R~2 = 0.977) with the exponential relationship. We then apply the correlation to estimate tree weight of the remaining trees. Next, the individual UAVs-based AGB was calculated based on the ratio of fresh weight and dry weight. The total AGB was 3450 kg ha~(-1).