Iron artwork

Encountered a special or unusual work of art during geocaching. For the time being unable to find any information about this. The small plates only contain dates, but nothing else. Possibly it has something to do with the resistance of cutting down a strip of forest in the years 1981 and 2016 for the runway of the AWACS planes in view of the chains attached to it. At the time, the demonstrators had been chained to the trees to be felled.