The No Man’s Land between the trenches of the clashing forces during World War I was a place you wouldn’t want to find yourself in. That is if you still love your life. Safe to say that it was the hottest part of the hellish battlefields of France at that time where death awaited from machine guns, flamethrowers, poison gas, and artillery rounds. And just as the soldiers thought they already had more than enough to worry about, they would find out that even the seemingly innocent, harmless, and war-beaten trees could also kill them.

The trees had eyes, and ears

OP Trees

In war, it was crucial to know your enemy’s moves and activity in order to gain a significant advantage over them. It was no surprise that the brilliant minds of the designers of World War I kept on finding ways how to make use and take advantage of the wreckage that separated their trenches from the enemies’. Germany, France, and Britain all tried to find ways to observe the enemy lines during World War I, but it was the French who came up with the brilliant idea in 1915 of using dead and hollowed-out trees as observation posts and then, later on, shared the idea with the British.

Honestly, why not? Who would suspect that a withering tree was actually alive and keeping an eye on your every movement? Not like in the creepy Evil Dead film with a demonic tree way but like in an enemy-observing-your-activities-way. You decide which is scarier.

Constructing the Tree

The process of creating and installing the tree was more complicated than it sounds. With both sides keeping an eye on each other closely, one couldn’t just stick a new “dead tree” because that would be obvious, and the operation would immediately be busted. It was, in fact, a tedious and time-consuming process.

It all started with the engineers surveying the No Man’s Land to find the shell-damaged tree in a suitable location. The tree had to be of the correct size and shape in the sense that a soldier could fit in once it was changed to the fake, OP tree ones. Once they found the perfect tree, they would measure, photograph, and sketch the tree in accurate detail, from its size to its bark.

These details would be sent to a workshop that would manufacture an exact replica of the tree based on the provided reference.

The artists and engineers would then tediously create an identical copy of the tree built around an armored tube. The bark would be made from wrinkled and folded iron, imitating its texture of it, and then painted to look as real as it could be. Twigs would then be added as necessary, as well as other features based on the original tree.

First World War artist Leon Underwood was one of the original camoufleurs, and his drawings were used in the manufacture of camouflage trees. First World War artist Leon Underwood was one of the original camoufleurs, and his drawings were used in the manufacture of camouflage trees. (Imperial War Museum via

Inside the armored tube was a ladder with a metal seat at the top. Sections of the tube were cut away and covered by a mesh so the observer seated at the top of the ladder could view his surroundings through his periscope. Whatever vital information he would gather would be relayed through a telephone or a messenger.

Not only were these trees used as observation posts, but they would sometimes house snipers.

Replacing the Tree

If creating the replica tree was already painstaking, then uprooting the real one and replacing it with the replica was even harder. Any activity in the No Man’s Land would be immediately noticed by the enemies and artillery and machine-gun fire down on you, so even quickly peeking over the trench parapet was already risky. So how do you get your 15-20ft tall fake iron tree into No Man’s Land,  dig out the real tree, and install the fake one?

Camouflaged Tree. (UK Ministery of Information, Public domain, via Wikimedia Commons)

To lower the risks, installing the OP tree was completed at night, accompanied by a pre-planned artillery barrage to cover the noise of the process. The entrance of the observation tree was sunk into the ground for it to be concealed; otherwise, an aerial photograph would immediately reveal the fake tree.

It was believed that the British first used these OP trees on a battlefield near Ypres and that there were a total of 45 of these trees used by them throughout World War I.

Two unidentified Australian officers examining a tree trunk that was used as an observation post at German House. (Courtesy of the Australian War Memorial)

Soon enough, the Germans caught on to the tactic and built their version called Baumbeobachter (tree observer), which they also used throughout the war. When the British captured the Oosttaverne area during the Battle of Messines, they discovered that one of the trees in the area was actually an observation tree disguised among the other similar-looking, war-torn trees.