DOI: 10.5281/zenodo.17491804
title: CGFEL – Quantitative structure modelling of TLS-scanned oak trees for centre-of-gravity and felling-force analysis

description: This dataset includes four ZIP archives and one CSV file containing detailed terrestrial laser scanning (TLS) and quantitative structure modelling (QSM) data, as well as simulation data, for 54 individual trees. It was generated to support analyses of tree geometry and centre of gravity estimation, as well as felling force simulations, in the context of forest operations and safety research.

Treescans.zip contains 54 terrestrial laser scan (TLS) files of individual trees in LAZ format. Each file corresponds to a single tree (e.g. B1.laz, B2.laz, etc.) and represents a filtered 3D point cloud acquired using a terrestrial laser scanner. These point clouds form the geometric basis for QSM reconstruction.

 

QSM_Trees.zip holds 54 Quantitative Structure Models (QSMs), each of which is derived from the corresponding (TLS) point cloud using MATLAB (TreeQSM). Each model is a hierarchical, cylinder-based representation of the tree architecture, enabling detailed volumetric and structural analyses. These models form the basis for calculations of mass distribution, centre of gravity and felling force.

 

The CSV_Treedata.zip archive includes three CSV files for each of the 54 trees, each documenting a different stage of the analysis:

a) _cylinder.csv

These files describe all individual cylinders of the QSM models and their physical properties.Column headers:



start_X, start_Y, start_Z, end_X, end_Y, end_Z: Global coordinates of the cylinder endpoints (m).

order: Topological cylinder order in the tree hierarchy.

radii: Cylinder radius (m).

height: Cylinder length (m).

local_start_X & local_end_Z: Local coordinates relative to the tree base.

local_mittel_X, local_mittel_Y, local_mittel_Z: Local midpoint coordinates of the cylinder.

Wichte: Assigned wood density (kg m⁻³) based on species-specific distributions.

error: Uncertainty in the measurements taken by the terrestrial laser scanner (m).

volume: Cylinder volume (m³).

G: Cylinder weight (N).

Ga_x, Gb_y, Gc_z: Weighted components of each cylinder’s centre of gravity along the three spatial axes.


b) _results.csv

These files contain aggregated results per tree derived from the cylinder-level data.

Column headers:



a, b, c: Resultant coordinates (X, Y, Z) of the whole tree (m).

sumG: Total tree weight-force (N).

schleifen_index_d: Iteration index identifier.


c) _results_df.csv

These files store the results of the Monte Carlo simulations and felling force calculations performed for each tree and direction.Column headers:



Winkel: Felling direction angle (°).

Delta_Y, Delta_Z: Lateral and vertical displacement of the tree’s CoG (m).

Mzz, Myy: Moments around the z- and y-axes (Nm).

E_X_koord, E_Y_koord: Coordinates of the resultant felling force in the horizontal plane (m).

eZ: Planar lever arm between the hinge centre and the point of application of the resultant force E (m).

bruchleiste_x, bruchleiste_y: Coordinates of the hinge line (“Bruchleiste”) (m).

in.poly: Indicator specifying if the resultant force lies inside (1–3) or outside (0) the hinge polygon.

E: Resultant felling force (kN).

schleifen_index_d: Iteration identifier.


 

The Plots.zip archive contains graphical outputs for each of the 54 trees, in both PDF and PNG formats. Each plot summarises the key results of the Monte Carlo simulations, including felling-force curves, force distributions and cross-sectional visualisations of the resultant forces. These figures offer a compact visual overview of the simulated felling scenarios, as well as the spatial variability of the trees' centres of gravity and resultant forces.

 

Simulationdata_FreET.csv includes the input parameters for the Monte Carlo simulations. These parameters define the wood-specific material properties that were used to calculate the mass distribution and felling forces.

Column headers:



Darrdichte_Stamm: Oven-dry wood density of the stem (kg/m³).

Darrdichte_Ast: Oven-dry wood density of the branches (kg/m³).

Wasser: Density of the water contained in the wood (kg/m³).

D_(0–20), D_(20–40), D_(>40): Errors in diameter measurement (cm) for the respective diameter classes (0–20 cm, 20–40 cm and >40 cm).