Last Thursday, environmental activists took their campaign against use of Amazon wood to the High Line park’s steps. They unfurled a banner along the wooden bleacher seats at 17th St. on the High Line, in a spot dubbed 10th Ave. Square. Ipê, a tropical hardwood, is used in the elevated park’s benches and seating. The activists displayed the banner 30 minutes without incident, as tourists and parkgoers read it and asked questions.