Sensor Placement on a Forwarder for Wildfire Ignition Risk Detection in Forest Harvesting Operations

Sammanfattning

When the risk of wildfires is elevated, large areas of forest are often restricted from harvesting, causing financial losses for forest companies. Consequently, there is a need to explore methods to mitigate this impact by reducing the size of the restricted zones. Two key factors for assessing the wildfire ignition risk posed by forwarders are the number of boulders in their path and the moisture level of the vegetation. This study aims to identify the most suitable sensor placement on a forwarder to estimate local wildfire ignition risk based on these factors. By exploring different sensor setups, including a LiDAR, RADAR, thermal camera, and RGB camera, this study determines the most effective setup for ignition risk detection. A case study was conducted to investigate a scenario that may be encountered when operating a forwarder. This involved a predefined route on a clear-felled area, where the ground truth regarding wildfire ignition risk indicators had been established – specifically, the number of stones that could potentially pose an ignition risk and the soil moisture content. During the study, sensor placement was varied for each run along the route, and the results were evaluated based on the accuracy, precision, and recall in identifying these wildfire ignition risks, along with the relevance of the data collected from each sensor position. Additionally, a qualitative analysis comparing the advantages and disadvantages of different sensor positions is included in the evaluation. The study concludes that the most suitable position for all sensors is at the front of the forwarder. However, the most suitable angle relative to the ground differs for each sensor: the LiDAR should be mounted at a 10–20° angle, the RADAR at a 90° angle, the thermal camera at a 30° angle, and the RGB camera at an angle of 30°. Here, 0° is defined as the forwarder’s direction of travel, and 90° is defined as pointing directly down to the ground.