Basically an aerial assault course built up in the trees. Zip lines, obstacles to navigate and some are pretty challenging. All graded like ski runs... green to black. In fact, the trees are between the pistes at Oslo Winterpark.Is a tree climbing park what it sounds like; a park specifically setup for climbing trees? If so, that's pretty cool. I was reading wikipedia on Oktoberfest yesterday, and they said tree climbing was part of the festivities in the 19th century. I thought that sounded interesting.