The Gangwon Provincial Assembly (Vice-chairperson: Cho Dong-yong) held a tree-planting event at the Unification Observatory in Goseong on April 6, 2015 or Arbor Day in Korea as a first step toward creating the Park of Peaceful Unification in order to celebrate the 70th anniversary of Korea's independence from Japanese colonial rule and to renew the determination to achieve peaceful unification.

Under the theme "I plant a tree of peace at the DMZ,” more than 200 people including local residents and council members joined the event. The participants planted 500 seedlings of their tree of choice and 300 pine tree seedlings across the Observatory and wished for the peaceful unification of the Korean Peninsula. The event was jointly hosted by the Gangwon Provincial Assembly, Gangwon Provincial Newspaper (president: Kim Jung-seok), Goseong of Gangwon-do (Governor: Yoon Seung-geun), and Eastern Regional Office of the Korea Forest Service (head: Lee Gyeong-il).

In connection with the event, a music concert for peaceful unification was concurrently held at the Goseong Culture and Welfare Center in Geojin-eup Office of Goseong and attended by over 300 local residents and council members.