Assessment of Forest Structural Diversity Differences in Mediterranean Landscapes Affected by Fires Using ALS Data

摘要

The objective of this research is to characterize the forest structural diversity of Mediterranean landscapes affected by wildfires in different dates. Methodology is based on the derivation of several variables related to the vertical structure and the horizontal continuity of vegetation calculated from Airborne Laser Scanner (ALS) data collected by the second coverage of the National Plan for Aerial Orthophotography of Spain (PNOA). The results show that the LHDI diversity index, the standard deviation, the canopy cover, the 99^{th and 95th percentiles and the standard deviation of the mean height of the laser returns, are the most useful metrics to analyze structural differences between wildfires. In contrast to old fires, recently burned areas have 80% laser returns below 3 m above the ground, which show a low index of structural diversity due to the predominance of the shrub layer. This study demonstrates the usefulness of low point density ALS data to accurately analyze the forest structural differences in a typical Mediterranean environment.}