Camouflaged road in Finland during the Continuation War (June 27, 1941)
They hung up trees with ropes about 10 kilometers from the Russian border to hide the road from airplanes.
It looks like it's not enough to cover the road but, when the road was viewed from an angle (not directly above) and a high altitude, the trees concealed enough of the road to make it difficult to identify as a road.
Okay, so the trees provide enough coverage despite the spacing, but did they have to change the trees every couple weeks when the needles turned brown and started to fall? Wouldn't the Russians notice a straight line of dead trees?
Very interesting! I'd imagine too that even if some of the road was still visible at different angles it still wouldn't really seem like a major roadway with the lines broken up by trees its much more likely to be dismissed as significant from the air.