How LiDAR tech reveals new details WW2's Battle of the Bulge

The battle lasted for several weeks and claimed tens of thousands of lives on both sides. It is considered one of the most important battles of World War II, but its impact on the environment has been largely overlooked, says Birger Stichelbaut, an archaeologist at Ghent University and the lead author of the study.

Stichelbaut and his team wanted to explore how the landscape influenced the movement and tactics of the troops, and how the battle left its mark on the terrain. But they faced a challenge: how to see through the thick canopy of trees that covers most of the battlefield. Traditional methods such as aerial photography or ground surveys were not effective enough.

LiDAR technology

They decided to use lidar(light detection and ranging), a technology that uses lasers to measure distances and create 3D maps of surfaces. Lidar can penetrate through vegetation and reveal features that are otherwise hidden. The researchers used a drone equipped with a high-resolution lidar scanner to fly over selected battlefield areas. They then processed the data with a computer algorithm to produce detailed maps of the ground.

The results were astonishing: they detected nearly 1000 archaeological features related to the battle, many of which had never been seen before. They found evidence of foxholes, dugouts, trenches, bomb craters, and artillery positions. They also traced how these features changed over time and space, reflecting the dynamics and intensity of the fighting.

One of the most striking findings was a cluster of foxholes near the village of Meyerode in Belgium, where a group of American soldiers from the 99th Infantry Division held off a German attack for several days. The lidar scans showed that the foxholes were arranged in a defensive pattern around a farmhouse that served as a command post. The scans also revealed that some of the foxholes were connected by tunnels, suggesting that the soldiers used them to communicate and move supplies.

By comparing these features with historical records of the battle, the researchers discovered new details about how some fights unfolded.

The researchers used lidar to detect a U.S. artillery position that had a unique “U” shape and faced east, where the German troops would have come from. This was reported by Science.org. They found many German hand grenades and spent cartridges when they explored the area on foot. This indicated that the U.S. soldiers had left the fortification in a hurry only to be taken over by the Germans troops.

New insights

The study revealed new insights into how the terrain affected the battle by examining the locations of these historical remains. The authors note that most of the remains were found on the edge of the forest, not in the open fields or deep inside the woods. This would have been a strategic place for troops to hide themselves.

David Cowley, an archaeologist at Historic Environment Scotland who was not part of the work, told Science.org that the analysis and interpretation had multiple scales. The lidar data and the on-site investigation could show insights from a single soldier digging a foxhole to “the global narrative of World War II.”

Stichelbaut explains that lidar has its limits. It can only see features on the ground surface, not buried artifacts. Logging has changed some parts of the Ardennes Forest after the battle, so some evidence may be gone forever. Stichelbaut says that the puzzle is not complete.

Dries Coucke, who co-authored the study, wants the team’s ongoing research to make Belgian officials recognize the forest as a heritage site and protect it from more damage. He also hopes that researchers will use machine learning in the future to map and interpret larger areas faster. He says that by mapping all these features, the team hopes to achieve “better protection and acknowledgment” for this important heritage.

The research was published in Antiquity

Study abstract:

Although conflict archaeology is now well established, the archaeological remains of many specific military confrontations are still to be explored. This article reports the results of fieldwork to document the site of the Battle of the Bulge (16 December 1944–25 January 1945). The authors use drone-mounted 1m-resolution LiDAR and very high-resolution simultaneous localisation and mapping (SLAM) methods to reveal more than 940 features within the forested Ardennes landscape, many of which were subsequently visited and confirmed. As well as highlighting the potential of the LiDAR-SLAM method, deployed here (both in this geographic region and conflict archaeology) for the first time, the survey results emphasize the need for a debate on managing the heritage of a key modern conflict landscape in Europe.