Landscape restoration achieved by massive reforestation in southeastern Korea

In order to restore regional landscape destroyed by excessive use and to prevent soil erosion, massive forestation project was practiced from 1973 to 1977 by South Korean government in southeastern Korea. Various woody species including both native and introduced species such as Korean red pine, black pine, black locust, and Manshurian alder were planted for the restoration project. We evaluated effects of the restoration practices by analyzing satellite images, vegetation attributes, and physico-chemical properties of soil. NDVI between natural and restored vegetation differed significantly before restoration in 1973 (p<0.0001). But the results in 2005 when 30 years passed after restoration did not show any differences. The result of stand ordination showed that planted stands were not fully restored to natural vegetation in terms of species composition. Comparing with native vegetation, higher proportion of annual and pioneer species such as Asteraceae and Gramineae occupied restored stands. But, juveniles and seedlings of native species were successfully established under canopy trees introduced artificially. Species diversity (H') was not significantly different between natural and restored stands, but species richness (p<0.0001) and evenness (p=0.0278) revealed significant differences. Soil properties were hardly rehabilitated compared with natural forest and earlier study. Those results imply that forest cover of this region was fully recovered, but attributes of forest ecosystem such as species composition, species richness, and soil properties were not restored completely yet. High proportion of ruderals in the restored stands imply that native seed sources were lack and artificial disturbances still existing, and thus ecological stability was not achieved yet. However, structural recovery of the reforested stands contributed to reducing soil erosion and thereby accomplishing structural stability of ecological system in this region.