Estimating Forest Variables from Lidar and Optical Sensors Using Artificial Intelligence
DOI:
https://doi.org/10.18172/cig.6767Keywords:
forest variables, remote sensing, time series, artificial intelligenceAbstract
Accurate and continuous characterization of forest fuel properties is essential for assessing wildfire risk and predicting fire behavior. This study addresses the limitations posed by the scarce temporal availability of lidar data by integrating temporally consistent optical imagery (Landsat) with occasional lidar acquisitions to estimate structural forest variables such as canopy cover fraction (FCC) and canopy height (H) in two regions of peninsular Spain: Madrid and the Basque Country. These variables are widely recognized as proxies for fuel properties characterization, reflecting both the amount and spatial continuity of forest fuels. Machine Learning (ML) models (Random Forest and Extreme Gradient Boosting) were compared with Deep Learning architectures, (DL) including transformer-based models with self-attention mechanisms (NeNeT).
The results show that DL models significantly improve accuracy, with an average reduction in root mean square error (RMSE) of 30% compared to traditional methods. NeNeT, in particular, demonstrated strong performance in capturing complex spatial relationships, improving height estimates in dense forests of the Basque Country (RMSE was reduced from 7.0 to 4.0 m). In contrast, differences were smaller in the more open Mediterranean forests of Madrid, suggesting that less computationally demanding methods like XGB may be suitable in certain contexts. Despite their advantages, DL models present operational limitations, particularly due to high computational demands. For instance, producing historical maps for the peninsular Spain would require up to four years of processing with NeNeT versus seven months with XGB, assuming no parallelization. Moreover, DL models tend to learn spurious patterns related to image acquisition (e.g., number of observations or dates), which can introduce biases if not properly controlled.
In conclusion, combining lidar and optical sensors with advanced artificial intelligence models enables highly accurate estimation of key variables for wildfire management. However, model choice should balance achieved precision with available computational resources, taking into account the ecosystem type and specific application needs.
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Copyright (c) 2025 Mihai Tanase, Juan Pablo Martini, Pablo Miranda, Daniel Garcia Garcia, Victoria Wilke, Jaime Diez, Sergio Natal, Daniel San Martin

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Grant numbers PID 2020-114062RA-I00;CNS 2022-135251