The forestation-sack method was used to restore damaged forestry areas on Mount Halla. That method is basically spreading out 40 cm by 60 cm green sacks filled with soil over the damaged area. In the early 1990s, the anchor-mat method, which involves covering terrain with net-shaped mats, was first used, but it failed to retain soil, so damage restoration procedures began to use the forestation-sack method.
Starting with the summit area of Nambyeok, until 2004, 11.5 billion won was invested and 58 percent of the deforested area, or 131,200 square meters, had restoration work done.
In areas where forestation-sacks had been laid, ten years later, 164 types of plants including sheep`s fescue, thyme, and Arabis serrata var. hallaisanensis, have begun to grow.
Thanks to sacks laid around hiking trails and trails tiled with wood blocks for easier hiking, trails that were virtually in ruins, such as the Eorimok trail, now have grass around them and a stable ecosystem.
As a result of using the forestation-sack method in heavily damaged areas such as the Mount Halla peaks of Nambyeok and Seobukbyeok, and the Eorimok trail, since 1994, plants have been covering a maximum of 90 percent of the land.
Koh Jeong-gun, head of the Hallasan Research Center research team, part of the Hallasan Park Management Office, said, Considering the current progress, plants will be restored at least ten years after forestation-sacks have been laid out.
The forestation-sack method that is being conducted on the deforested areas of Mount Halla is now virtually in its last stages, and although there remain damaged areas, most of them were caused by natural causes.
Prior to that, with the surge of hikers in Mount Halla starting in the 1970s, hiking trails and their adjacent areas were greatly damaged. Part of the problem was that Mount Halla is composed of igneous rocks easily susceptible to cracking and volcanic soil which is not very cohesive, making its rate of erosion faster than that of other mountains.
In 1993, 195,300 square meters, including the trail between Eorimok and Uitsaeoreum and part of the summit, were reported as damaged areas, and in 2000, when restoration work was being conducted, 225,800 square meters were verified as damaged.
Some, however, argue that the forestation-sack method caused the excessive spreading of Chejujoritdae (Sasa quelpaertensis) and resulted in artificially meddling with Hallas ecosystem.
Cheju National University Professor Kim Moon-hong argued, Alpine plants lost their ground with the laying of forestation-sacks on Mount Halla. Areas that are being covered with these sacks should be carefully chosen.
In the early stages of forestation-sack laying, soil containing low-altitude plant seeds was placed in the mountain, and 53 alien plans such as clover and orchard grass streamed in.
Koh said, In order not to make the same past mistakes, we are collecting samples of native Halla plants and then annually sowing them in forestation sacks.
Head of the Hallasan Park Management Office Lee Gwang-chun said, It is reasonable to leave the damage caused by natural causes to nature itself. Now, we should work on long-term monitoring of plant succession and changes, and also in training a professional workforce to protect the Halla ecosystem.