Putting up a camouflage tree (artwork by GC Leon Underwood, 1919)

When British forces captured the Oosttaverne Wood from the Germans during the Battle of Messines in June 1917, they were surprised to find that one of the trees wasn’t a tree at all—it was a steel-and-iron imitation. This camouflaged “tree” had been used by the Germans as an outlook post to spy on the British lines without being detected.

The German “tree” found in Oosttaverne Wood

The British and French also used metal “trees” for observation during World War I. The Germans called the “trees”Baumbeobachter, which literally means “tree observer.” Because the enemy frontlines were watched so closely, any obvious observation methods would be easily spotted. So both sides used Baumbeobachters since they could easily blend into their surroundings.

The Baumbeobachters were hollow steel tubes covered by iron “bark” texturized to look like the real thing. The base of the steel tree widened and was buried in the ground to provide support. The observer would access the top of the observation post by climbing inside through a small opening close to the ground then ascending a narrow ladder, not much wider than a man’s boot. The rungs of the ladder were not very far apart, as the small circumference of the interior would prevent anyone from taking large steps. Once the observer climbed the ladder, he would sit on a small seat attached to the side of the tube. The seat was lower than the sight holes so any bullets or shrapnel that made it in through those openings wouldn’t directly hit the person inside; instead the observer used a periscope to see out.

An Australian-built Baumbeobachter

When an army decided they needed a Baumbeobachter, they would find a real tree in a location where they wanted their observation post. They’d have to choose a place along their frontline that was fairly static to put their Baumbeobachter; otherwise, if the line moved, the post would be useless. Then they’d take a picture of the real tree, and the Baumbeobachter would be made to look exactly like the existing tree. Once the army had the fake tree, they would cut down the real tree at night (sometimes under the cover of artillery fire to hide the sound), then put the Baumbeobachter exactly where the old tree was. That way, when the opposing army looked over in the morning, nothing would rouse their suspicions since everything looked exactly the same.

Read more about the Baumbeobachter here, here, or here. Or listen to a curator at the Australian War Memorial discuss their structure and use. You can also find more stories from the war in Fold3’s World War I collection.

Watching from the Trees