How can one estimate the height of trees in remote, inaccessible areas?  This was one aspect Stefan Reder and Lillie Waßermann addressed in their Bachelor’s thesis. The two IFEM graduates from HNEE did research on the possible use of UAVs forstructural and successional analysis in rainforest areas in Ecuador and Brazil and developed an applicable, cost-efficient workflow.

They combined the photogrammetric method Structure from Motion (SfM) with a digital terrain model (DTM) from the Shuttle Radar Topography Mission (SRTM). In this way, they added relief information from photogrammetric point clouds (PPC) representing the upper canopy layers.

Based on ground points extracted from a 3D model, a vertical shift of the model was made to fit the ellipsoidal plane of the PPC. The digital surface models (DSM) of 22 study plots were normalised to tree canopy height models (CHM) to allow estimation of relative tree heights in all study plots without using ground control points (GCP).

The results of Stefan Reder and Lilli Waßermann – i.e. the calculated tree height values – demonstrate the applicability of the workflow also in tropical rainforests with dense canopy. Their approach enables the classification of tree canopy structures for the identification of forest succession and other ecological forest monitoring purposes.

The results of their research illustrate the potential of 3D models for tree height estimation derived from PPCs based on UAV (Unmanned Aerial Vehicle) imagery in rainforest research. Details of the work by Stefan Reder and Lillie Waßermann are published in the GI Journal or visit their story map.


Stefan Reder – contact for research in the field of UAV and neutral networks stefan.reder (at)hnee.de

Review his research paper:
UAV-based Tree Height Estimation in Dense Tropical Rainforest Areas in Ecuador and Brazil