Tomoko told me something of the park's history. It was formerly the site of US Army Camp Chikamauga, but now stands as a peace park and testament to post-war good will between the two nations.
The soldiers stationed here planted a small pine tree, which they decorated at Christmas time. This tree now stands 60 feet tall and beside it is a plaque commemorating "the kindnesses shown by troops of the 19th Infantry Regiment to the people of Beppu". Local people still decorate this tree every Christmas.
Tomoko also told me about a soldier who returned recently, to visit his former camp, and how he was moved to tears by the sight of that tree, that he himself had helped to plant so many years ago. (You can read his own personal account of his return visit to Beppu here)