Back in January of 2013, the Monday Buzz spoke with artist Erika Koivunen about her commission to construct a massive iron “gateway tree” sculpture to welcome people to Madison’s Marquette neighborhood. At the time, Erika had asked people to donate recyclable scrap metal to her studio on South Park Street for use in the structure. Well, you can stop bringing your old shovels, pickaxes and rebar, thank you very much. The sculpture is nearly complete, and with installation day approaching, Brian Standing caught up with Erika and her husband and collaborator Aaron Howard at their studio.