Automatic Processing of Aerial LiDAR Data to Detect Vegetation Continuity in the Surroundings of Roads

Ana Novo,Noelia Fariñas-Álvarez,Henrique Lorenzo,Higinio González-Jorge,Joaquin Martínez-Sánchez

doi:10.3390/rs12101677

Abstract

The optimization of forest management in the surroundings of roads is a necessary task in term of wildfire prevention and the mitigation of their effects. One of the reasons why a forest fire spreads is the presence of contiguous flammable material, both horizontally and vertically and, thus, vegetation management becomes essential in preventive actions. This work presents a methodology to detect the continuity of vegetation based on aerial Light Detection and Ranging (LiDAR) point clouds, in combination with point cloud processing techniques. Horizontal continuity is determined by calculating Cover Canopy Fraction (CCF). The results obtained show 50% of shrubs presence and 33% of trees presence in the selected case of study, with an error of 5.71%. Regarding vertical continuity, a forest structure composed of a single stratum represents 81% of the zone. In addition, the vegetation located in areas around the roads were mapped, taking into consideration the distances established in the applicable law. Analyses show that risky areas range from a total of 0.12 ha in a 2 m buffer and 0.48 ha in a 10 m buffer, representing a 2.4% and 9.5% of the total study area, respectively.

Highlights

Spain is included in the top five European countries with the highest number of wildfires
As Unmanned Aerial Vehicle (UAV) Light Detection and Ranging (LiDAR) data, to map year-by-year burnt areas, like Galicia, is fundamental to generate more information and contribute to effective forest management. The detection of these areas in Galicia is carried out by manual methods and, this study presents a new point of view to improve the current work methodology
The aim of this study is to analyse the potential of using UAV-based LiDAR to map the continuity of vegetation and mapping risky areas subject to forest fires

Summary

Introduction

Spain is included in the top five European countries with the highest number of wildfires. In 2019, 10,648 forest fires were registered in Spain, of which 43.23% happened in the north west of Spain according to data from the Ministry of Agriculture, Fisheries and Food [1] One of these northern regions, Galicia, is one of the most important forest areas in Europe and holds its own legislation regarding forest firefighting [2]. Roads are a key element in forest fire fighting, both providing access to wildfires during extinguishing tasks and acting as linear firebreaks that avoid or reduce fire spread. These factors can be useful in both fire suppression and prescribed fire operations. The benefits that roads provide for fire prevention and fire management carry an associated maintenance cost [3]

Objectives

Methods

Findings

Discussion

Conclusion