Artificial Trees

One to file under Today I learned: The concept of Observation Post Trees, deployed in the first world war. Those trees were completely artificial, and, ever more interestingly, would replace actual trees with a almost indistinguishable double:

To develop the O.P. Tree, Royal Engineers representatives selected, measured, and photographed the original tree, in situ, extensively. The ideal tree was dead; often it was bomb blasted. The photographs and sketches were brought back to the workshop, where artists constructed an artificial tree of hollow steel cylinders, but containing an internal scaffolding for reinforcement, to allow a sniper or observer to ascend within the structure. Then, under the cover of night, the team cut down the authentic tree and dug a hole in the place of its roots, in which they placed the O.P. Tree. When the sun rose over the field, what looked like a tree was a tree no longer; rather, it was an exquisitely crafted hunting blind, maximizing personal concealment and observational capacity simultaneously.

As the BLDGBLOG notes:

But there's something almost comedically paranoid about the idea that, upon waking up tomorrow morning, a tree—or rock or, for that matter, a whole hillside—has been surreptitiously replaced by an artificial surrogate, an exactly designed stand-in or double, in a ruse about which you otherwise remain unaware. It happens again—and again, perhaps for an entire season—before one day you finally stumble upon incontrovertible evidence that the entire forest through which you hike every weekend has been filled with incredibly precise, hollow representations of trees through which someone appears to be spying on you.

More info in the book Hide and Seek, ᔥBLDGBLOG.