The stalemate in the trenches during The Great War meant the two sides were evenly matched, so even the smallest advantage for one could mean the difference between defeat and victory. A small but extremely useful tactic employed on the sparse battlefields was replacing trees with camouflaged observation posts.
This method of keeping tabs on your enemy’s activity was used by Germany, France, and Britain during WWI, but the French came up with the idea first in 1915 and later shared their knowledge with the British.
An observation tree seems like a simple concept, but the process behind creating one was extremely precise and time-consuming. A tree was not simply adapted for this use, but actually completely removed and replaced with an identical-looking fake tree, with the specific purpose of being used for observation. Just sticking a new tree in the ground would immediately be noticed by the enemy.
To begin with, engineers would have to find a (usually shell-damaged) tree in a suitable location and of the correct size and shape. Once the right tree had been chosen, it would be measured, photographed, and sketched in detail, to document every feature of the tree, from its size all the way down to its bark.
This in-depth record of the tree’s exterior was then sent to a workshop as a reference for manufacturing an exact replica.
Engineers and artists would then painstakingly create an identical copy of the original tree. The entire thing was built around an armored tube. Bark would be made from folded and wrinkled iron, which was covered in a rough texture and then painted to look as real as possible. Visually identical limbs and twigs would be added, as well as any other shapes and features from the original tree.
Inside the armored tube, a ladder was fitted, which was topped with a metal seat. When in the field, an observer would climb the ladder and place himself on the seat at the top to view his surroundings. Sections of the tube would be cut away and covered by a mesh, which allowed the observer to see out.
But for more detailed observation of the battlefield, a periscope would be used. This meant the soldier could see out while remaining safely inside the armored tree.
The observer would pass on what he was seeing from his vantage point via a telephone or a messenger. Alternatively, the tree would be used as a sniper’s nest.
Installing the fake tree
Once the tree was made, engineers had the tough job of installing it. Any movements would be noticed by the enemy and immediately fired upon; even quickly peaking over the parapet of a trench was considered risky.
To put the new tree in place, the old one had to first be removed. After it had been uprooted, a hole was dug where it once sat, and the new tree was dropped in. An obvious pathway into the tree would stand out on enemy aerial reconnaissance, so the entrance was disguised.
To avoid detection, this entire operation had to be completed overnight, while a pre-planned artillery barrage or gunfire drowned out the noisy process.
The next day, the tree that had potentially been there for centuries had been removed and replaced with a man-made replica, all without the enemy knowing anything had changed.
Observation trees proved incredibly effective as they were almost impossible to detect, especially when placed amongst other trees. They were installed all along the front.
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The Germans did eventually catch on though and began making their own equally impressive versions. These were called baumbeobachter, which meant “tree observer.”
In 1917, the Allied forces managed to push the Germans out of Oosteverne Woods in Belgium. It took them several weeks to realize one of the trees near their position was actually a baumbeobachter disguised amongst the war-torn forest.