Where:
CS represents the predicted carbon stock.
LiDAR represents LiDAR-derived features (e.g., CHM, canopy
density, structural diversity metrics).
Satellite represents satellite-derived features (e.g., NDVI, EVI,
surface temperature).
Hyper-spectral represents hyper-spectral reflectance indices (e.g.,
Normalized Difference Vegetation Index - NDVI, Red Edge
positions).
?????? represents the optimal hyperparameters of the RF model,
determined through BHO.
A targeted Bayesian Optimization algorithm, utilizing Gaussian
Processes (GPs) to model the response surface, is employed to
automatically tune the RF’s hyperparameters (e.g., number of trees,
maximum tree depth, minimum samples per leaf) leading to a
maximized R
2
score. Mathematically, the BHO can be described as:
??????* = argmax
??????
E[f(??????)]
Where:
??????* is the optimal set of hyperparameters.
E[f(??????)] represents the expected value of the RF model performance
(e.g., R
2
score) as a function of hyperparameters ??????.
3. Experimental Design & Data Analysis
The ISLRF system was evaluated over a network of 50 forest plots
representing diverse forest types across North America and Europe.
Drone-based LiDAR surveys were conducted within each plot,
complemented by simultaneous satellite imagery and hyper-spectral
reflectance measurements. Ground-truth carbon stock data, obtained
from standard field measurements (e.g., tree diameter, height, species
identification, litter collection), were used as reference data for model
validation.
3.1 Performance Metrics & Reliability:
Model performance was evaluated using standard regression metrics,
including R
2
score, Root Mean Squared Error (RMSE), and Mean Absolute
Error (MAE). A 10-fold cross-validation approach was implemented to
assess the robustness and generalizability of the model. Significance
•
•
•
•
•
•
•