Massive-scale tree modelling from TLS data

P. Raumonen^a E. Casella^b K. Calders^c S. Murphy^d M. Åkerblom^a M. Kaasalainen^a

^aTampere University of Technology, Tampere, Finland ^bForest Research, Farnham, UK ^cWageningen University, Wageningen, Netherlands ^dMelbourne School of Land and Environment, University of Melbourne, Australia

• Compact tree model with topology and geometry.
• Branching structure &
  branching order.
• Volumes, lengths, angles, etc.
• Hierarchical collection of cylinders.

• TLS from a few positions around tree.
• Manually extract single tree.
• Reconstruct a QSM.
• Total biomass from QSMs overestimated by 9.7% while local allometric equations show an underestimation between 29.9% and 36.6%. (65 sampled Eucalyptus trees, Calders et al. 2015)

• Accurate biomass estimates.
• Ground truth data for airborne measurements.
• Cheap measurements.
• Biomass estimation non-destructively.

• Perform TLS from several locations inside a forest plot.
• Register to single point cloud.
• Plot-level: tree extraction
• Remove ground and under-growth.
• Automatically extract trees based on segmentation.
• Tree-level reconstruction
• Segment into branches.
• Reconstruct each branch with multiple cylinders.

• Remove points outside plot.
• Remove some ground and under-story points.
• Remove low point density regions and small separate clusters.
• Make high point density regions sparser.
• Large reduction in point count.

• Partition the point cloud into small subsets corresponding surface patches in tree and other surfaces.
• Use the patches and heuristics to locate the stems.
• Patch surface normal approximately horizontal.
• Large patch components define the stems.

• Segment the patches into stems and branches.
• Restrict the trees inside the plot.

• South-Eastern England
• Species: Quercus robur L.
• Five scans, leaf-off
• Leica HDS-6100
• Reference biomass from
  allometric equation.

• Victoria, Australia
• Species: Eucalyptus leucoxylon,
  E. microcarpa and E. tricarpa.
• RIEGL VZ-400
• Reference biomass
  from destructive
  harvesting of 27 trees.

Computations: MacBook Pro 2.8GHz, 16GB, Matlab.

• Fast and accurate massive scale tree modelling is possible from TLS data.
• Tree extraction and modelling in hours.
• Total plot level biomass were overestimated by 8% and 15% in the test cases.
• The method seems to be robust.
• Two different plots with different species, scanners and resolutions.
• Parameters tested for sensitivity.
• Multi-hectare forest regions possible.

Questions?