Those trees are watching you: The incredible role of 'camouflage trees' in WWI

As a military innovation, camouflage trees worked as disguised observation posts that were made to resemble war-damaged tree trunks already scattered across no-man’s-land.

Each one concealed a hollow steel column with internal steps or foot pegs, along with a small platform for a soldier to observe enemy movements as he peered through a narrow slit or periscope.

Engineers only placed these trees after they had identified actual trees with clear views of enemy trench systems.

Once a target had been selected, artists conducted a careful survey of the tree’s exact shape, damage patterns, lean angle, bark texture, and surrounding debris. 

Early in 1915, French forces developed what appears to have been the first successful model near Soissons under the guidance of Lucien-Victor Guirand de Scévola, a painter who led France’s camouflage unit and had previously trained at the École des Beaux-Arts in Paris.

After they had witnessed their usefulness, British commanders ordered the formation of their own Camouflage Section within the Royal Engineers in 1916 under the direction of Solomon Joseph Solomon, a respected portrait artist connected to the Royal Academy.

German forces also experimented with tree posts, though fewer documented examples exist compared to the Allied use of such posts. 

Initially, construction often occurred in rear-area workshops, where sculptors and engineers used battlefield sketches to replicate every detail.

They began with a welded steel frame strong enough to hold a man’s weight. Then they attached wire mesh and canvas coverings over carved wood, and in this way they reproduced the exact look of shattered bark and battlefield wear.

Bullet holes and scorch marks, along with the look of tangled roots, had to be mimicked as closely as possible.

Engineers painted the exterior with mud-stained colours that matched the surrounding terrain, and all materials were chosen for their ability to blend in well with the surrounding ground from both near and distant viewing points.

Typically, each tree stood between three and six metres tall and weighed several hundred kilograms once completed, as taller models proved difficult to transport and install. 

For the soldier inside, a camouflage tree offered cover but no comfort. Once sealed within the tight shaft, the observer endured hours of complete stillness and silence while only a narrow slit or periscope connected him to the battlefield.

Engineers typically positioned the tree within rifle range of enemy lines, so it attracted constant risk.

Even a faint glint from the periscope lens could sometimes invite a sniper’s bullet or an artillery barrage, and many trees were eventually destroyed once enemy observers noticed small differences or spotted movement, often during bad weather. 

From within, the soldier recorded the movement of enemy supply lines, the construction of new trench systems, or the placement of artillery.

In some sectors, the observer relayed real-time targeting instructions to batteries via field telephone, which often ran through the trench system but stayed vulnerable to weather and bombardment.

At times, however, these lines failed due to weather, shellfire, or sabotage, which meant the observer had to memorise details and wait for rotation before passing on his notes.

In rare cases, soldiers survived the destruction of their post and returned with critical information, though this was uncommon. 

Conditions inside the tree were punishing. During summer, the confined space turned into an airless oven, while winter transformed it into a frozen coffin.

Since observers could not shift position without risk, they often experienced muscle cramps and faintness that sometimes led to blurred vision.

In the absence of light or fresh air, moisture often clouded the lens and pooled at the soldier’s feet. Still, he stayed, because a single mistake could cost lives. 

To maintain the deception, the observer trained to stay still for long periods.

Trained to resist basic urges like coughing or scratching, he controlled every movement, and he knew that even the slightest disturbance might end his life.

Occasionally, a tree was abandoned after a lucky shell strike exposed its artificial core, but often the observer disappeared along with the tree when it was destroyed. 

To deploy a camouflage tree, military engineers had to carry out a highly coordinated and dangerous operation under cover of darkness.

Once a suitable dead tree had been identified, artists and scouts crawled into no-man’s-land at night to sketch its appearance and measure its dimensions.

They recorded the angle of its lean, the direction of branch stumps, the shapes of nearby shell holes, and even the mud splashes across the bark, since these details ensured that the artificial replacement would match its environment perfectly. 

After this scouting, construction began in a sheltered workshop. Engineers built the internal core from steel piping with a base plate for anchoring, then lined the inside with a ladder and an observation platform.

Then sculptors and painters layered the tree with shaped wood and mesh that was wrapped in painted canvas to mimic natural textures.

At times, they attached real fragments of bark to increase realism. Before the tree had left the workshop, the team often compared it to photographs to verify its camouflage.

In total, the construction of a single tree could take several days to a week, and the time depended on the detail. 

Installation usually took place under immense pressure, and to minimise exposure, engineers typically chose a night during an artillery bombardment or storm to mask sound and movement.

The team carried tools as they crawled across no-man’s-land, removed the original tree using ropes or levers, and dropped the artificial one into place using prepared holes or sandbag reinforcements.

Sometimes, they dug a shallow pit around the base to match the shapes of the old stump. Once erected, the tree had to stay motionless and convincingly lifeless by first light. 

After the switch, the observer climbed inside before sunrise and began his watch.

If the enemy failed to detect the change, the tree could provide days of uninterrupted watching, but any suspicion could lead to sudden enemy gunfire. 

Since camouflage trees offered a concealed and static viewpoint near enemy lines, they gave clear tactical value across many sectors of the Western Front.

Artillery batteries frequently relied on tree-based reports to adjust their fire with greater accuracy.

Observers often helped identify newly constructed saps, tunnel entrances, and gun positions before they could be used against Allied lines.

During operations at Vimy Ridge and Messines Ridge, Allied forces used tree posts to track enemy troop build-up and plan early bombardments that disrupted German counter-attacks.

At Vimy Ridge in April 1917, for instance, tree-based observers contributed to the detailed artillery planning that enabled Canadian forces to take the ridge, though the success still came at the cost of over 10,000 casualties. 

Since weather often grounded reconnaissance aircraft and artillery spotting balloons proved vulnerable to enemy fire, trees provided a stable alternative.

Observers could often monitor changes over time, spot unusual activity, or catch shifts in daily routines.

From a single tree, an experienced soldier could track patrol routes and ration deliveries, plus the timing of artillery rotations, since in some cases this information was information that sometimes directly influenced the timing and direction of infantry assaults. 

Although eventually the trees wore out their usefulness as front lines moved or were identified by enemy fire, many stayed operational for weeks.

Their success largely depended on the discipline of the observer and the build quality, supported by the constant reinforcement of the illusion.

Once discovered, enemies often responded with overwhelming force, destroying the tree and the observer within seconds. 

Today, the Australian War Memorial houses one of the few surviving examples, a silent steel cylinder that once mimicked a tree near Armentières.

It was recovered after the war and brought to Canberra as a rare artefact, and it measured over six metres in height and weighed more than 400 kilograms.