SimpleForest

SimpleForest reconstructs three-dimensional tree models from terrestrial laser scan point clouds for quantitative structural analysis of trees in forest plots.

Key Features:

• Automated Pipeline: Models ground surface using a Digital Terrain Model (DTM), segments vegetation, and constructs Quantitative Structure Models (QSMs) of individual trees.
• Quantitative Structure Models (QSMs): Represents trees as thousands of topologically ordered cylinders corresponding to branches and stems, enabling calculation of diameter at breast height and volume.
• Structural and Novel Metrics: Computes traditional forestry metrics and novel parameters including Growth Volume, Growth Length, Vessel Volume, and Reverse Pipe Radius Branch order (RPRB).
• Volume Prediction Accuracy: Predicts tree volume with concordance correlation coefficients (CCC) of 0.91–0.97 against multiple datasets with destructive sampling.
• RPRB-Based Correction: Defines RPRB as the square root of the number of supported twigs and uses it to predict and correct overestimated cylinder radii relying solely on topological information.
• Radius Correction Model: Applies a linear radius prediction radius = B0 × RPRB, achieving CCC up to 0.97 compared with previously published CCCs of 0.80–0.86.
• Modeling Assumptions: Integrates Pipe Model Theory and the West, Brown, and Enquist model (self-similarity of twigs) as underlying assumptions.

Scientific Applications:

• Structural analysis and biomass estimation: Provides precise tree structure and volume estimates for forest biomass and carbon studies.
• Growth dynamics and structural ecology: Enables analysis of growth patterns and structural dynamics using Growth Volume, Growth Length, Vessel Volume, and RPRB.
• Method validation: Supports validation and comparison of QSM-derived metrics against datasets obtained by destructive sampling.

Methodology:

Models ground surface with a Digital Terrain Model, segments vegetation, constructs QSMs composed of topologically ordered cylinders, computes RPRB as the square root of the number of supported twigs, and applies the radius correction radius = B0 × RPRB; modeling assumptions include the Pipe Model Theory and the West, Brown, and Enquist model.