Damyang is a region of heavy rainfall, and flood damage was a recurring problem historically. To prevent this, in 1648 (the 26th year of King Injo's reign), Damyang's magistrate Seong I-seong built a levee and began planting trees on top of it. What started as a reforestation project with the practical purpose of flood prevention became, in time, the beginning of the forest known today as Gwanbangjerim.
About 206 years later, in 1854 (the fifth year of King Cheoljong's reign), another Damyang magistrate, Hwang Jong-rim, repaired this same levee and replanted the forest anew. The largest trees in Gwanbangjerim today are said to date back 300 to 400 years — to the period when Seong I-seong first built the levee — while the relatively smaller trees are known to have been planted in 1854 (the fifth year of King Cheoljong's reign) by Hwang Jong-rim. This forest, grown from trees planted across two separate eras, represents a case in which the result of a practical flood-control project was transformed, over the passage of time, into a natural heritage site. Gwanbangjerim is today designated a Natural Monument.